CN103245692B - Steady-state analysis-based method for measuring hemispherical total emissivity and heat conduction coefficient - Google Patents

Abstract

The invention specifically discloses a method for measuring hemispherical total emissivity and thermal conductivity based on steady-state analysis. The steps include: selecting a long and thin strip-shaped conductor material sample, heating it with electricity in a vacuum environment, and selecting a section in the middle The area is the test area, according to the steady-state energy balance equation of the steady-state calorimetry method; the hemispherical total emissivity and thermal conductivity are expressed as mathematical functions of temperature; multiple sets of steady-state measurement experiments are carried out under different steady-state temperature conditions, Construct the steady-state energy balance equations under different steady-state temperature conditions; find out the undetermined parameters in the equations, and determine the hemispherical total emissivity and thermal conductivity of the sample under different steady-state temperature conditions. The invention is applicable to the measurement of the hemispherical total emissivity of various conductor materials under the condition of unknown thermal conductivity, and can also obtain the thermal conductivity value of the conductive material, avoiding the uncertainty brought by the unknown thermal conductivity to the hemispherical total emissivity measurement sexual influence.

Description

Measurement method of hemispherical total emissivity and thermal conductivity based on steady-state analysis

technical field

The invention relates to the field of hemispherical total emissivity measurement of conductive materials, in particular to a method for simultaneous measurement and inversion of hemispherical total emissivity and thermal conductivity of conductive materials based on steady-state calorimetric analysis.

Background technique

Hemispherical total emissivity is one of the important thermophysical parameters of materials, which characterizes the surface thermal radiation ability of materials, and is an important basic physical property data for the study of radiation measurement, radiation heat transfer and thermal efficiency analysis. With the wide application of new materials in high-tech fields such as energy power and aerospace, more urgent needs have been put forward for the measurement of hemispherical total emissivity. Compared with other thermal physical parameters, the hemispherical total emissivity measurement method The technical research is still insufficient, and the hemispherical full emissivity data of different materials is still lacking, and it is necessary to obtain the hemispherical full emissivity of the object through precise experimental measurement.

At present, the methods for measuring the hemispherical total emissivity of materials mainly include radiation spectroscopy and calorimetry. Calorimetry is widely used because of its simple equipment structure, convenient operation, and high accuracy. It can be divided into transient calorimetry and steady-state calorimetry. The experimental principle of steady-state calorimetry is to calculate the hemispherical total emissivity of the material surface by measuring the heat transfer and surface temperature of the sample in thermal equilibrium. Researchers at home and abroad have adopted different sample specifications and heating methods to form A variety of steady-state calorimetry application modes have been developed. For example:

a. In the vacuum chamber, the heating plate is used to heat the bottom surface of the material, and the full-wavelength emissivity of the material is calculated by measuring the current, voltage and the temperature of the upper surface of the material;

b. Put two sample thin slices on both sides of the heating plate, hang them in the vacuum chamber by the wires of the heating plate, heat them with electric current, and calculate the hemispherical total emissivity by measuring the electric power and the surface temperature of the material;

c. Select a slender strip sample to be heated by electricity in a vacuum environment (called hot wire method), and regard the area with a relatively uniform temperature in the center of the strip sample as the test analysis area, thereby ensuring the temperature and energy measurement of the sample test analysis area accuracy. At present, some people have measured the emissivity of oxidized and non-oxidized Inconel 718 samples, 304 stainless steel and molybdenum, but the types of materials are limited, and the thermal conductivity of materials must be known, which limits this method. The measurement range and measurement effect of the measurement method.

In the measurement and calculation model of the hemispherical total emissivity of conductive materials based on steady-state calorimetry analysis, the correction of thermal conductivity and heat loss in the strip sample test area is a key link to be considered. However, when the thermal conductivity of the tested material is unknown, How to solve the thermal conduction heat loss calibration of the sample test area will be one of the main difficulties in solving the material hemisphere to full emissivity. Therefore, it is very necessary to develop a method for simultaneous measurement of high-temperature hemispherical total emissivity and thermal conductivity for the testing of conductive materials under the condition of unknown thermal conductivity.

Contents of the invention

(1) Technical problems to be solved

The purpose of the present invention is to provide a method for measuring the hemispherical total emissivity and thermal conductivity based on steady-state analysis, to overcome the situation of unknown sample thermal conductivity when the existing steady-state calorimetry measures the hemispherical total emissivity In this case, the calibration of heat conduction heat loss in the sample test area cannot be performed.

(2) Technical solutions

In order to solve the above technical problems, the present invention provides a method for measuring hemispherical total emissivity and thermal conductivity based on steady-state analysis, the steps of the method include:

S1. Select a slender strip-shaped conductor material sample, heat it under vacuum environment, select a section of the middle area of the sample as the test area, and establish the steady-state energy balance equation of the sample according to the steady-state calorimetry;

S2. Expressing the hemispherical total emissivity and thermal conductivity of the sample as a mathematical function about temperature, quantitatively characterizing the hemispherical total emissivity and thermal conductivity of the sample with undetermined parameters in the function;

S3. Carry out multiple sets of steady-state measurement experiments under different steady-state temperature conditions, construct multiple steady-state energy balance equations under different steady-state temperature conditions, and form a steady-state energy balance equation group, the sample hemisphere to the full emissivity function and the undetermined parameters in the thermal conductivity function are unknowns in the equation system;

S4. Utilize the numerical solution algorithm to obtain the undetermined parameters in the sample hemispherical total emissivity function and thermal conductivity function, obtain the hemispherical total emissivity function and thermal conductivity function of the sample with respect to temperature, thereby determine the sample in different stable Hemispherical total emissivity and thermal conductivity at state temperature.

Wherein, the steady-state energy balance equation in the step S1 is:

$\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}$

In the formula, Q is the heating electric power of the sample test area, which can be obtained by measuring the voltage and current at both ends of the sample test area, and is a known quantity; (T ₀ , T ₁ , T ₂ ) are the left boundary and middle , The temperature value of the right boundary, obtained by thermocouple measurement, is a known quantity; is the average temperature of the test area in the sample, is a known quantity; T _e is the temperature of the vacuum water wall, which is a known quantity; ε is the hemispherical total emissivity of the sample, which is an unknown quantity; λ is the thermal conductivity of the sample, which is an unknown quantity; σ is the Steven-Boltzmann A constant is a known quantity; the length of the sample test area is l, the width is w, the thickness is d, the cross-sectional area of the sample is A=w d, and the surface area of the test area S=2l (w+d), all of which are known quantities .

Wherein, the hemispherical total emissivity function and the thermal conductivity function of the sample in the step S2 are one of a linear function, a power exponential function and a polynomial function with a finite number of undetermined parameters.

Wherein, the hemispherical total emissivity function and thermal conductivity function of the sample in the step S2 can be expressed as a linear function of temperature within the temperature interval bandwidth ΔT, and the function is:

$\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ;</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ \mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ;</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\end{array}\right.$

In the formula, (a ₁ , a ₂ ) are two undetermined parameters in the hemispherical total emissivity function; (b ₁ , b ₂ ) are two undetermined parameters in the thermal conductivity function; T is the steady state of the sample test area temperature.

Wherein, after substituting the hemispherical total emissivity function and the thermal conductivity function into the steady-state energy balance equation in the step S3, it is:

${\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ;</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ;</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}$

In the formula, Q _i is the heating electric power of the sample test area at the i-th steady-state temperature, which is a known quantity; (T _i,0 ,T _i,1 ,T _i,2 ) are the i-th steady-state temperature states The temperature values of the left boundary, the middle and the right boundary of the sample test area below are obtained by thermocouple measurement and are known quantities; is the average temperature of the sample test area at the i-th steady-state temperature, is a known quantity.

Among them, within the temperature interval bandwidth ΔT, select G different steady-state temperature conditions to conduct steady-state measurement experiments on the sample test area, G is greater than or equal to the sum of the undetermined parameters of the hemispherical full emissivity function and thermal conductivity function, The resulting steady-state energy balance equations are:

$\left\{\begin{array}{c}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1,0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1,2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1,1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\\ <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2,0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2,2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2,1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>\\ <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; G</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; G</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; G</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}}\end{array}\right.$

In the formula, (a ₁ , a ₂ , b ₁ , b ₂ ) are unknown undetermined coefficients, and the four undetermined parameters (a ₁ , a ₂ , b ₁ , b ₂ ), so as to obtain the hemispherical total emissivity function and thermal conductivity function of the sample with respect to temperature.

Wherein, the length of the elongated strip conductor material sample is much greater than its width and thickness.

Wherein, the temperature gradient difference in the sample testing area is less than 10°C.

Wherein, in the step S1, the two ends of the elongated strip-shaped sample are fixed on the sample holder, placed in a vacuum chamber with a water-cooled inner wall, the vacuum chamber is evacuated, and the two ends of the sample are energized and heated to a certain steady state temperature state.

Wherein, the steady-state measurement experiment in the step S3 is carried out within a temperature range

(3) Beneficial effects

The present invention expresses the hemispherical total emissivity and thermal conductivity of conductor material samples as mathematical functions about temperature respectively, brings them into the steady-state energy balance equation, and then establishes measurement equations under different steady-state temperature conditions to calculate Solve the undetermined parameters in the equation group to obtain the hemispherical total emissivity function and thermal conductivity function of the sample, so that the hemispherical total emissivity and thermal conductivity of the sample at different temperatures can be calculated. The present invention is applicable to the unknown thermal conductivity Under the measurement of the hemispherical total emissivity of various conductor materials, and while calculating and solving the hemispherical total emissivity of the conductive material, the thermal conductivity value of the conductive material will also be obtained at the same time, avoiding the unknown thermal conductivity. Uncertainties brought about by rate measurement.

Detailed ways

Embodiments of the present invention are described in further detail in the following examples. The following examples are used to illustrate the present invention, but should not be used to limit the scope of the present invention.

The measurement method of hemispherical total emissivity and thermal conductivity based on steady-state analysis in this embodiment is applicable to the simultaneous measurement of hemispherical total emissivity and thermal conductivity of strip-shaped conductor material samples (hot wires) with a small temperature gradient test area. The measurement overcomes the difficult problem of solving the hemispherical total emissivity under the condition that the thermal conductivity of the conductor material to be tested is unknown. The steps include:

S1. Select a slender strip-shaped conductor material sample, fix both ends of the sample on the sample holder, place it in a vacuum chamber with a water-cooled inner wall, evacuate the vacuum chamber to 1.0×10 ^-3 Pa, and energize both ends of the sample Heating to a certain steady-state temperature state, select a small area in the middle of the sample as the test area, the temperature gradient is small, the temperature difference is less than 10°C, the length of the sample is much greater than its width and thickness, the sample test area can be regarded as It is a one-dimensional steady-state heat conduction problem along the length direction, ignoring the heat conduction loss of the thermocouple wire on the surface of the sample and the heat conduction loss of the gas in the vacuum chamber, the steady-state energy balance equation of the sample test area is established according to the steady-state calorimetry method as :

$\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}$

In the formula, Q is the heating electric power of the sample test area, which can be obtained by measuring the voltage and current at both ends of the sample test area, and is a known quantity; (T ₀ , T ₁ , T ₂ ) are the left boundary and middle , The temperature value of the right boundary is obtained by thermocouple measurement and is a known quantity. Since the temperature gradient of the sample test area is small, the temperature values of the three points are relatively close; is the average temperature of the test area in the sample, is a known quantity; T _e is the temperature of the vacuum water wall, which is a known quantity; ε is the hemispherical total emissivity of the sample, which is an unknown quantity; λ is the thermal conductivity of the sample, which is an unknown quantity; σ is the Steven-Boltzmann A constant is a known quantity; the length of the sample test area is l, the width is w, the thickness is d, the cross-sectional area of the sample is A=w d, and the surface area of the test area S=2l (w+d), all of which are known quantities .

S2. Within a certain temperature interval (temperature interval bandwidth ΔT), the hemispherical total emissivity and thermal conductivity of the actual object are simple to express, and the two thermophysical parameters of hemispherical total emissivity and thermal conductivity can usually be used with the temperature Simple mathematical functions ε(a ₁ ,a ₂ ,a ₃ ,…,a _N ;T) and λ(b ₁ ,b ₂ ,b ₃ ,…,b _M ;T) are described, in the hemispherical total emissivity function The undetermined parameters (a ₁ ,a ₂ ,a ₃ ,…,a _N ) characterize the characteristics of the hemispherical total emissivity, and the undetermined parameters in the thermal conductivity function (b ₁ ,b ₂ ,b ₃ ,…,b _M ) The characteristic of the thermal conductivity is characterized, and the mathematical function may be one of a linear function, a power exponential function and a polynomial function with finite undetermined parameters.

In this embodiment, within the bandwidth of the temperature range of ΔT=200°C, a linear function is used to describe the hemispherical total emissivity and thermal conductivity of the conductor material sample, and the function is:

$\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ;</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ \mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ;</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\end{array}\right.$

In the formula, (a ₁ , a ₂ ) are two undetermined parameters in the hemispherical total emissivity function; (b ₁ , b ₂ ) are two undetermined parameters in the thermal conductivity function; T is the temperature range of the sample test area A steady-state temperature within the bandwidth ΔT.

S3. Substituting the functions in S2 into the steady-state energy balance equation in S1, it can be seen that the sufficient and necessary conditions for solving the four undetermined parameters (a ₁ , a ₂ , b ₁ , b ₂ ) are at ΔT=200℃ Within the bandwidth of the temperature range, at least four steady-state measurement experiments under different temperature conditions are carried out to construct the measurement equation system, that is, at least four steady-state measurement experiments under different temperature conditions are carried out to satisfy the mathematical closure of the undetermined parameters Solving needs.

The selected sample heating temperature range is 800°C to 1000°C. In this range, a set of hemispherical total emissivity function and thermal conductivity function can be used. The number of undetermined parameters is four. Adjust the heating power of the sample. At this temperature The samples were heated to five steady-state temperature states within the range (i.e. ), in addition, in each steady-state temperature state, the temperature gradient in the middle test area of the sample is small, and the temperature difference is less than 10°C. According to the above-mentioned five different steady-state temperature points, five sets of steady-state measurement experiments are carried out, and five The steady-state energy balance equations under different steady-state temperature conditions form a steady-state energy balance equation group, which is:

$\left\{\begin{array}{c}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1,0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1,2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1,1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\\ <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2,0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2,2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2,1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 3,0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 3,2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 3,1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}\\ <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 4,0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 4,2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 4,1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}\\ <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 5,0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 5,2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 5,1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}\end{array}\right.$

The undetermined parameters (a ₁ , a ₂ , b ₁ , b ₂ ) in the sample hemispherical total emissivity function and thermal conductivity function are unknowns in the above equations;

S4. Use the numerical solution algorithm to solve the four unknowns (a ₁ , a ₂ , b ₁ , b ₂ ) of the steady-state energy balance equations in S3, and invert to obtain the hemispherical total emissivity function and thermal conductivity of the sample with respect to temperature function to determine the hemispherical total emissivity and thermal conductivity of the sample under different temperature conditions within the temperature range (bandwidth ΔT=200°C).

The preferred temperature range in this embodiment is 300°C to 2000°C. If the bandwidth of the temperature range for sample investigation is greater than 200°C, for example, the temperature range is 800°C to 1600°C, then the temperature range can be divided into 800°C to 1000°C according to ΔT=200°C ℃, 1200℃～1400℃, 1400℃～1600℃, in each temperature range, follow the above measurement steps to determine the undetermined parameters in the hemispherical total emissivity and thermal conductivity function of each zone, and then determine The sample hemispherical total emissivity and thermal conductivity values.

The present invention can also be solved with other functions, and after substituting the selected hemispherical total emissivity function and thermal conductivity function into the steady-state energy balance equation, it is:

${\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; ;</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; ;</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}$

In the formula, Q _i is the heating electric power of the sample test area at the steady-state temperature of the i-th group, which is a known quantity; i=1,2,...,G, G is the group number of the steady-state measurement experiment under different temperature conditions, It is greater than or equal to the sum of the number of _undetermined parameters of the hemispherical total emissivity function _and the thermal conductivity function _; The temperature values of the left boundary, the middle and the right boundary of the test area are obtained by thermocouple measurement and are known quantities. Since the temperature gradient of the sample test area is small, the temperature values of the three points are relatively close; is the average temperature of the sample test area at the i-th steady-state temperature, is a known quantity.

According to the above-mentioned steady-state energy balance equation, hemispherical total emissivity function and thermal conductivity function, through a method similar to the above-mentioned embodiment, that is, using a numerical solution algorithm, by measuring known quantities, the hemispherical total emissivity function can be calculated. Undetermined parameters (a ₁ , a ₂ , a ₃ ,…,a _N ) and undetermined parameters (b ₁ ,b ₂ ,b ₃ ,…,b _M ) in the thermal conductivity function, and then determine the Sample hemispherical total emissivity and thermal conductivity.

The embodiments of the present invention have been presented for purposes of illustration and description, but are not intended to be exhaustive or to limit the invention to the form disclosed. Many modifications and changes will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to better explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention and design various embodiments with various modifications as are suited to the particular use.

Claims (9)

1. a method for measuring the hemispherical total emissivity and thermal conductivity based on steady-state analysis, it is characterized in that the steps of the method comprise: S1. Select a slender strip-shaped conductor material sample, heat it under vacuum environment, select a section of the middle area of the sample as the test area, and establish the steady-state energy balance equation of the sample according to the steady-state calorimetry; The steady-state energy balance equation is: $\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}$ In the formula, Q is _the heating electric power of _the sample test area, which can _be obtained by measuring the voltage and current at both ends of the sample test area, and is a known quantity; The temperature value of the boundary, obtained by thermocouple measurement, is a known quantity; is the average temperature of the test area in the sample, is a known quantity; T _e is the temperature of the vacuum water wall, which is a known quantity; ε is the hemispherical total emissivity of the sample, which is an unknown quantity; λ is the thermal conductivity of the sample, which is an unknown quantity; σ is the Steven-Boltzmann A constant is a known quantity; the length of the sample test area is l, the width is w, the thickness is d, the cross-sectional area of the sample A=w d, and the surface area of the test area S=2l (w+d), all are known quantities ; S2. Expressing the hemispherical total emissivity and thermal conductivity of the sample as a mathematical function about temperature, quantitatively characterizing the hemispherical total emissivity and thermal conductivity of the sample with undetermined parameters in the function; S3. Carry out multiple sets of steady-state measurement experiments under different steady-state temperature conditions, construct multiple steady-state energy balance equations under different steady-state temperature conditions, and form a steady-state energy balance equation group, the sample hemisphere to the full emissivity function and the undetermined parameters in the thermal conductivity function are unknowns in the equation system; S4. Utilize the numerical solution algorithm to obtain the undetermined parameters in the sample hemispherical total emissivity function and thermal conductivity function, obtain the hemispherical total emissivity function and thermal conductivity function of the sample with respect to temperature, thereby determine the sample in different stable Hemispherical total emissivity and thermal conductivity at state temperature. 2. the method for measuring the hemispherical total emissivity and thermal conductivity based on steady-state analysis according to claim 1, is characterized in that, the hemispherical total emissivity function and thermal conductivity function of sample in the described step S2 are to contain limited One of a linear function, a power exponential function and a polynomial function with undetermined parameters. 3. the method for measuring the hemispherical total emissivity and thermal conductivity based on steady-state analysis according to claim 2, characterized in that, the hemispherical total emissivity function and thermal conductivity function of the sample in the step S2 are within the temperature interval Within the bandwidth ΔT, it can be expressed as a linear function of temperature, the function is: $\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ;</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ \mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ;</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\end{array}\right.$ In the formula, a ₁ , a ₂ are two undetermined parameters in the hemispherical total emissivity function; b ₁ , b ₂ are two undetermined parameters in the thermal conductivity function; T is the steady-state temperature of the sample test area. 4. the method for measuring the hemispherical to total emissivity and thermal conductivity based on steady state analysis according to claim 3, is characterized in that, in described step S3, hemispherical to total emissivity function and thermal conductivity function are substituted into steady state energy After balancing the equation is: ${\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ;</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ;</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}$ In the formula, Q _i is the heating electric power of the sample test area at the steady-state temperature of the i-th group, which is a known quantity; T _i,0 , T _i,1 , T _i,2 are respectively The temperature values of the left boundary, middle and right boundary of the sample test area are obtained by thermocouple measurement and are known quantities; is the average temperature of the sample test area at the i-th steady-state temperature, is a known quantity. 5. the method for measuring the hemispherical total emissivity and thermal conductivity based on steady-state analysis according to claim 4, is characterized in that, in the temperature range bandwidth ΔT, choose G different steady-state temperature conditions to sample test area Carry out the steady-state measurement experiment, G is greater than or equal to the sum of the undetermined parameters of the hemispherical total emissivity function and the thermal conductivity function, and the obtained steady-state energy balance equations are: $\left\{\begin{array}{c}(a_1{\stackrel{\&OverBar;}{T}}_1+a_2)\&Center\; Dot;S\&Center\; Dot;\mathrm{\&sigma;}\&Center\; Dot;({\stackrel{\&OverBar;}{T}}_1^4-T_e^4)-(b_1{\stackrel{\&OverBar;}{T}}_1+b_2)\&CenterDot;A\&CenterDot;(T_{\mathrm{1,0}}+T_{\mathrm{1,2}}-{2T}_{\mathrm{1,1}})/l=Q_1\\ (a_1{\stackrel{\&OverBar;}{T}}_2+a_2)\&CenterDot;S\&CenterDot;\mathrm{\&sigma;}\&CenterDot;({\stackrel{\&OverBar;}{T}}_2^4-T_e^4)-(b_1{\stackrel{\&OverBar;}{T}}_2+b_2)\&Center\; Dot;A\&Center\; Dot;(T_{\mathrm{2,0}}+T_{\mathrm{2,2}}-{2T}_{\mathrm{2,1}})/l=Q_2\\ \&Center\; Dot;\&CenterDot;\&CenterDot;\\ (a_1{\stackrel{\&OverBar;}{T}}_G+a_2)\&CenterDot;S\&CenterDot;\mathrm{\&sigma;}\&CenterDot;({\stackrel{\&OverBar;}{T}}_G^4-T_e^4)-(b_1{\stackrel{\&OverBar;}{T}}_G+b_2)\&Center\; Dot;A\&Center\; Dot;(T_{G,0}+T_{G,2}-2T_{G,1})/l=Q_G\end{array}\right.$ In the formula, a ₁ , a ₂ , b ₁ , b ₂ are unknown undetermined coefficients, and the four undetermined parameters a ₁ , a ₂ , b ₁ , The specific numerical value of _b2 , thereby obtains the hemispherical total emissivity function and thermal conductivity function of the sample with respect to temperature. 6. The method for measuring hemispherical total emissivity and thermal conductivity based on steady-state analysis according to claim 1, wherein the length of the elongated strip conductor material sample is much greater than its width and thickness. 7. The method for measuring hemispherical total emissivity and thermal conductivity based on steady-state analysis according to claim 6, characterized in that the temperature gradient difference in the sample test area is less than 10°C. 8. The method for measuring the hemispherical total emissivity and thermal conductivity based on steady-state analysis according to claim 7, wherein, in the step S1, the two ends of the elongated strip sample are fixed on the sample holder, placed In a vacuum chamber with a water-cooled inner wall, the vacuum chamber is evacuated, and the two ends of the sample are energized and heated to a certain steady-state temperature state. 9. according to the measuring method of hemispherical total emissivity and thermal conductivity based on steady-state analysis according to any one of claims 1-8, it is characterized in that, the steady-state measurement experiment in the described step S3 is in a temperature range within.