CN110207852B - A system and method for rapid measurement of airflow enthalpy value of arc heater - Google Patents

Abstract

A system and method for rapid measurement of airflow enthalpy value of an arc heater, which are based on the conservation of thermal mass flow rate and cold state mass flow rate during operation of the arc heater, and rapidly evaluate airflow temperature, combined with the quantification of airflow enthalpy value and temperature and pressure under thermal equilibrium conditions relationship, the total enthalpy of the arc heater gas flow can be obtained. The airflow enthalpy value can be directly obtained by using the pressure of the cold and hot air in the arc heater. Based on this method, the airflow enthalpy value of the aircraft ground thermal protection test can be obtained quickly, which is beneficial to the development of large-scale aircraft aerodynamic thermal ground test. It is used to measure the airflow enthalpy of various types of arc heaters such as tubular, AC, segmented, and laminated. It is also suitable for the determination of airflow enthalpy of various test media such as air, _CO2 , _N2 , Ar

Description

A system and method for rapid measurement of airflow enthalpy value of arc heater

technical field

The invention relates to the measurement of simulated airflow parameters in the ground test of an aircraft, which is used for the measurement of the airflow enthalpy of electric arc heaters such as tubular, segmented, and thick laminations, and belongs to the research field of aerodynamic thermal tests on the ground of aircraft.

Background technique

The arc heater is an important test platform for studying the aerodynamic thermal protection of aircraft, and its working state and airflow quality directly determine the reliability of the test. At present, the existing arc heater equipment mainly includes lamination, segment, tubular and other methods, covering the measurement range from high enthalpy to low enthalpy.

Existing enthalpy measurement methods are currently widely used mainly energy balance method. The energy balance method is to multiply the input power (arc voltage × arc current) by an efficiency coefficient and divide by the mass flow of the gas supply as the total gas enthalpy, The determination of the efficiency coefficient in routine tests is often given empirically. The second is the equilibrium sound velocity method, which obtains the enthalpy according to the empirical formula proposed by Winovich by assuming that the airflow in front of the nozzle throat is in thermal equilibrium, isentropy, univariate homogeneous flow, and steady conditions. The air flow enthalpy value is calculated according to the pressure at the electric stage in front of the device, the upstream air flow rate and the throat area of the nozzle, and the enthalpy loss between the nozzles is ignored. Equilibrium sound velocity method is currently the most widely used method for calculating enthalpy in arc wind tunnel test. At the same time, the stagnant point enthalpy can also be measured by using the method of stagnation ball head heat measurement and stagnation point pressure measurement, and its measurement accuracy depends on the accuracy of heat flow measurement and pressure measurement. The error of the enthalpy value is basically about 10%-20%, and the enthalpy value conversion coefficient given by different empirical formulas changes from 112 to 123.5, which further increases the uncertainty of the enthalpy value measurement.

SUMMARY OF THE INVENTION

The technical solution of the present invention is to propose a rapid measurement system and method for the air flow enthalpy value of an arc heater. Based on the conservation of the mass flow rate in the hot state and the mass flow rate in the cold state in the test of the electric arc heater, the temperature of the air flow can be quickly evaluated, and the air flow under thermal equilibrium conditions can be quickly evaluated. The quantitative relationship between the enthalpy value and temperature and pressure can obtain the total enthalpy of the air flow of the arc heater. The method is not limited to a certain type of arc heater, and can be applied to determine the flow field enthalpy value of various types of arc heaters, such as tubular, alternating current, segmented, and laminated. At the same time, the method is not limited to the determination of the enthalpy value of the air medium, and can be applied to the determination of the enthalpy value of various test media such as air, CO ₂ , N ₂ , and Ar.

The technical scheme of the present invention: a rapid measurement system for the air flow enthalpy value of an electric arc heater, comprising a mixed pressure stabilization chamber, a pressure sensor and a real-time enthalpy value measurement unit; The cold airflow is mixed to adjust the airflow and stabilize the pressure. The mixed airflow is expanded and accelerated by the external nozzle to form a supersonic airflow at the nozzle outlet. The state pressure P _hot and the cold state pressure P _cold when the external arc heater is not working, and the two pressure values are output to the enthalpy real-time measurement unit; the enthalpy real-time measurement unit is based on the mass flow conservation during the operation of the arc heater, using P The two pressures of _heat and P _cool are used to evaluate the total airflow temperature T _heat when the external arc heater is working, and the measurement of the total airflow enthalpy is realized according to the obtained total airflow temperature T _heat and P _heat .

The method of determining the airflow enthalpy of the external arc heater through the enthalpy real-time measurement unit is as follows:

1) Calculate the airflow flow of the arc heater:

表示为温度和压力的函数f(T,P)，P、T分别代表混合稳压室内气体的压力和温度，A^*为外部喷管的喉道面积；Among them, γ and M are the gas specific heat ratio and gas molar mass in the mixing plenum, respectively, and R ₀ is the universal gas constant. Under the condition of thermal equilibrium, the above γ and M are functions of the gas temperature and pressure in the mixing plenum;

It is expressed as a function of temperature and pressure f(T, P), where P and T represent the pressure and temperature of the gas in the mixing plenum, respectively, and A ^* is the throat area of the external nozzle;

2) According to the mass flow of hot state when the external arc heater is working and the mass conservation of cold state flow when it is not working, obtain the total gas temperature in the mixing chamber:

Among them, T _cool and P _cool are the temperature and pressure of the gas when the external arc heater is not working, and T _heat and P _heat are the temperature and pressure of the gas when the external arc heater is working;

3) Based on the above-mentioned total gas temperature in the mixing plenum, iterative calculation is used, assuming that the first iteration f(T _heat , P _heat ) ₁ = f(T _cold , P _cold ), according to the pressure P _heat measured in the mixing plenum and the pressure P _cold , the total airflow temperature T _{heat 1} of the mixing plenum is obtained, and the subscript 1 represents the first iteration;

4) Based on obtaining the initial value of the total gas temperature in the mixing plenum, iterative calculation is performed to obtain the final total airflow temperature T in the mixing plenum. _The specific method is:

Based on the calculated total airflow temperature T _{heat 1} and pressure P _heat , calculate new r ₂ , M ₂ , subscript 2 represents the second iteration, obtain f(T _heat , P _heat ) ₂ and obtain the total airflow temperature T _{heat 2} ; Start the iteration, when the total airflow temperature T _{heat N} - the total airflow temperature T _{heat N-1} converges, the iteration ends, and the total airflow temperature T _{heat N} is the final total airflow temperature T _heat of the gas in the mixing plenum; otherwise, continue Perform iterative calculation; subscript N represents the Nth iteration, N≥2;

5) According to the final airflow total temperature T _heat and P _heat in the mixing plenum chamber obtained above, based on the relationship between the airflow enthalpy value, temperature and pressure in the thermodynamic equilibrium high temperature gas parameter relationship: H=H(T, P), obtain the external The gas flow enthalpy H of the arc heater.

The gas flow enthalpy value H=H(T, P) in the thermodynamic equilibrium high temperature gas parameter relationship is obtained by NASA thermochemical equilibrium calculation.

表示为温度和压力的函数f(T,P)，f(T,P)利用NASA热化学平衡计算获得。said

Expressed as a function of temperature and pressure f(T,P), f(T,P) is calculated using NASA's thermochemical equilibrium.

The T _cold is the temperature of the gas when the external arc heater does not work, and is accurately measured by a thermometer or a K-type thermocouple.

The pressure sensor is a strain-type pressure sensor with a range of 0-1MPa or 0-2MPa or 0-15MPa.

The mixing pressure chamber is made of red copper material.

The external arc heater is a tubular low-enthalpy arc heater, or a segmented medium-enthalpy arc heater, or a laminated high-enthalpy arc heater.

The nozzle is an axisymmetric conical supersonic nozzle or a rectangular supersonic nozzle.

A method for quickly measuring the airflow enthalpy of an arc heater, the steps are as follows:

1) Mixing pressure chamber, mix the hot air flow generated by the external arc heater with another part of the cold air flow, adjust the air flow and stabilize the pressure, the mixed air flow is expanded and accelerated by the external nozzle and formed at the outlet of the nozzle (3) supersonic airflow;

2) The pressure measuring device measures the pressure in the mixing plenum, respectively measures the hot state pressure P _hot when the external arc heater is working and the pressure value P _cold when the external arc heater is not working, and outputs the two pressure values to the enthalpy value real-time measurement unit;

3) The enthalpy value real-time measurement unit (5) is based on the conservation of mass flow during the operation of the arc heater, using the two pressures of P _hot and P _cold , to obtain the total airflow temperature T _hot when the external arc heater is working through iterative calculation, and further based on the thermal The relationship between the gas flow enthalpy value and temperature and pressure is obtained by chemical equilibrium calculation, and the measurement of the gas flow total enthalpy is realized by using the obtained gas flow total temperature T _heat and P _heat .

The advantages of the present invention compared with the prior art are as follows:

(1) The present invention is based on the conservation of the mass flow in the hot state when the arc heater is in operation and the mass flow in the cold state when the arc heater is not in operation, and can realize the rapid acquisition of the total airflow temperature, and further utilize the quantitative relationship between the airflow enthalpy value and temperature and pressure to achieve Measurement of total enthalpy of gas flow for arc heaters.

(2) The present invention can realize the measurement of the air flow enthalpy value of the arc heater through the pressure measurement, and can realize the real-time acquisition of the pressure and the real-time acquisition of the enthalpy value, and has great convenience and simplicity for the debugging of the aerodynamic hot ground test state, The efficiency of test debugging is improved, which is conducive to the development of model ground tests.

(3) Based on the physical definition of airflow enthalpy value, temperature and pressure, the present invention realizes the extraction of airflow enthalpy value, eliminates the influence of the error of the engineering empirical formula itself on the enthalpy value measurement, and can realize more accurate enthalpy value measurement.

(4) The method of obtaining the airflow temperature and enthalpy value based on the pressure measurement of the present invention is suitable for determining the enthalpy value of various test media such as air, CO2, N2, Ar, etc. Measurement method limitations for enthalpy determination.

Description of drawings

FIG. 1 is a schematic layout diagram of a system and method for rapid measurement of airflow enthalpy value of an arc heater according to the present invention.

Fig. 2 is the flow chart of the rapid measurement method of gas flow enthalpy of the present invention;

Figure 3 is a comparison between the new method of airflow enthalpy value of the present invention and the traditional balanced sound velocity method.

Detailed ways

Below in conjunction with accompanying drawing and embodiment, the present invention is described in further detail:

FIG. 1 is a schematic layout diagram of a system and method for rapid measurement of airflow enthalpy value of an arc heater according to the present invention. It can be seen from the figure that a rapid measurement system for the airflow enthalpy value of an arc heater of the present invention includes a mixing pressure chamber 2 , a pressure sensor 4 , and a real-time enthalpy value measurement unit 5 .

The mixing pressure chamber 2 mixes the hot air flow generated by the external arc heater 1 with another part of the cold air flow to adjust the air flow and stabilize the pressure. ;

The pressure measuring device 4 measures the pressure in the mixing pressure chamber 2, respectively measures the _hot state pressure Phot when the external arc heater 1 is working and the _cold state pressure Pcold when the external arc heater 1 is not working, and compares the two pressure values. output to the enthalpy real-time measurement unit 5;

The enthalpy real-time measurement unit 5 is based on the conservation of mass flow during the operation of the arc heater, and uses the two pressures of P _hot and P _cold to evaluate the total airflow temperature T _heat when the external arc heater 1 is working, and further based on the above-obtained total airflow temperature T _Heat and P _heat , enabling the measurement of the total enthalpy of the gas flow.

The enthalpy real-time measurement unit 5 determines the airflow enthalpy of the external arc heater 1 as follows:

(1) Calculate the airflow flow of the arc heater:

Among them, γ and M are the gas specific heat ratio and the gas molar mass in the mixing pressure chamber 2, respectively. Under the condition of thermal equilibrium, the above γ and M are functions of the gas temperature and pressure in the mixing plenum 2, P and T respectively represent the pressure and temperature of the gas in the mixing plenum 2, and A ^* is the throat of the external nozzle 3 area;

(2) According to the mass flow rate of the hot state when the external arc heater 1 is working and the mass conservation of the cold state flow rate when it is not working, obtain the calculation method of the total temperature of the gas in the mixing pressure chamber 2:

Wherein T _cool and P _cool are the _temperature and pressure of the gas when the external arc heater 1 is not working, and T and P are the _temperature and pressure of the gas when the external arc heater 1 is working;

(3), based on the calculation method of the total temperature of the gas in the above-mentioned mixed pressure chamber 2, obtain the initial value T _{heat 1} of the total temperature of the gas in the mixed pressure chamber 2:

Iterative calculation is adopted, assuming the first iteration f(T _heat , P _heat ) ₁ = f(T _cold , P _cold ), according to the pressure P _hot and pressure P _cold measured in the mixing plenum 2, the mixing plenum 2 is obtained The total airflow temperature T _{heat 1} , the subscript 1 represents the first iteration;

(4), based on obtaining the initial value of the total temperature of the gas in the mixing pressure chamber 2, perform iterative calculation to obtain the final total airflow temperature T _heat in the mixing pressure chamber 2:

Based on the calculated T _{heat 1} and pressure P _heat , calculate new r ₂ , M ₂ , and the subscript 2 represents the second iteration; substitute the above formula to obtain f(T _heat , P _heat ) ₂ , and calculate according to the above formula to obtain T heat ₂ . Iterate as described above. When T heat _N - T heat _N-1 converges, the iteration ends, and T heat _N is the final total airflow temperature T _heat of the gas in the mixing plenum 2; otherwise, the iterative calculation is continued. The subscript N represents the Nth iteration, N≥2.

(5), according to the total temperature T _heat and P heat of the final gas flow in the mixing pressure chamber 2 obtained above, based on the relationship between the gas flow enthalpy value and temperature and pressure in the thermodynamic equilibrium high temperature gas parameter relationship: H=H(T,P ) to obtain the airflow enthalpy value H of the external arc heater 1 .

In the above step (5), the relationship between the gas flow enthalpy value and the temperature and pressure, H=H(T,P), is obtained by using NASA thermochemical equilibrium calculation.

表示为温度和压力的函数f(T,P)，f(T,P)利用NASA热化学平衡计算获得。In the above step (1)

Expressed as a function of temperature and pressure f(T,P), f(T,P) is calculated using NASA's thermochemical equilibrium.

In the above step (2), T _cool is the temperature of the gas when the external arc heater 1 is not working, which can be accurately measured by a thermometer or a K-type thermocouple.

The above-mentioned pressure sensor 4 is a strain-type pressure sensor with a range of 0-1MPa or 0-2MPa or 0-15MPa.

The above-mentioned mixing pressure chamber 2 is made of red copper material.

The above-mentioned external arc heater 1 is a tubular low-enthalpy arc heater, or a segmented medium-enthalpy arc heater, or a laminated high-enthalpy arc heater.

The above-mentioned nozzle 3 is an axisymmetric conical supersonic nozzle or a rectangular supersonic nozzle.

The invention takes the 10MW laminated arc heater as an example, uses pressure measurement, and combines the relationship between the airflow enthalpy value, temperature and pressure to realize the measurement of the airflow enthalpy value of the arc heater.

As shown in Figure 2, it is the flow chart of the method for measuring the enthalpy of gas flow rapidly according to the present invention, and the method for measuring the enthalpy of gas flow rapidly according to the present invention specifically includes the following steps:

Step (1), the mixing pressure chamber 2 mixes the hot air flow generated by the external arc heater 1 with another part of the cold air flow, adjusts the air flow and stabilizes the pressure, and the mixed air flow is expanded and accelerated by the external nozzle pipe 3 at the nozzle pipe. 3 The outlet forms supersonic airflow;

Step (2), the pressure measuring device 4 measures the pressure in the mixing stabilizing chamber 2, respectively measures the hot state pressure P _heat when the external arc heater 1 works and the cold state pressure P _cold when the external arc heater 1 does not work, and Output the two pressure values to the enthalpy real-time measurement unit 5;

Step (3), the enthalpy real-time measurement unit 5 is based on the conservation of mass flow during the operation of the arc heater, and uses the two pressures of P _heat and P _cold to evaluate the total airflow temperature T _heat of the external arc heater 1 when working, and further obtain based on the above. The total airflow temperature T _heat and P _heat to achieve the measurement of the total enthalpy of the airflow.

The method for determining the airflow enthalpy of the external arc heater 1 by the above-mentioned enthalpy real-time measuring unit 5 is as follows:

(1) Calculate the airflow flow of the arc heater:

Among them, γ and M are the gas specific heat ratio and the gas molar mass in the mixing pressure chamber 2, respectively. Under the condition of thermal equilibrium, the above γ and M are functions of the gas temperature and pressure in the mixing plenum 2, P and T respectively represent the pressure and temperature of the gas in the mixing plenum 2, and A ^* is the throat of the external nozzle 3 area;

(2), according to the mass flow of the hot state when the external arc heater 1 is working and the mass conservation of the cold state flow when it is not working, obtain the calculation method of the total gas temperature in the mixing pressure chamber 2:

Wherein T _cool and P _cool are the _temperature and pressure of the gas when the external arc heater 1 is not working, and T and P are the _temperature and pressure of the gas when the external arc heater 1 is working;

(3), based on the calculation method of the total temperature of the gas in the above-mentioned mixed pressure chamber 2, obtain the initial value T _{heat 1} of the total temperature of the gas in the mixed pressure chamber 2:

Iterative calculation is adopted, assuming the first iteration f(T _heat , P _heat ) ₁ = f(T _cold , P _cold ), according to the pressure P _hot and pressure P _cold measured in the mixing plenum 2, the mixing plenum 2 is obtained The total airflow temperature T _{heat 1} , the subscript 1 represents the first iteration;

(4), based on obtaining the initial value of the total temperature of the gas in the mixing pressure chamber 2, perform iterative calculation to obtain the final total airflow temperature T _heat in the mixing pressure chamber 2:

Based on the calculated T _{heat 1} and pressure P _heat , calculate new r ₂ , M ₂ , and the subscript 2 represents the second iteration; substitute the above formula to obtain f(T _heat , P _heat ) ₂ , and calculate according to the above formula to obtain T heat ₂ . Iterate as described above. When T heat _N - T heat _N-1 converges, the iteration ends, and T heat _N is the final total airflow temperature T _heat of the gas in the mixing plenum 2; otherwise, the iterative calculation is continued. The subscript N represents the Nth iteration, N≥2.

(5), according to the total temperature T _heat and P heat of the final gas flow in the mixing pressure chamber 2 obtained above, based on the relationship between the gas flow enthalpy value and temperature and pressure in the thermodynamic equilibrium high temperature gas parameter relationship: H=H(T,P ) to obtain the airflow enthalpy value H of the external arc heater 1 .

The above-mentioned pressure sensor 4 is a strain-type pressure sensor with a range of 0-1MPa or 0-2MPa or 0-15MPa.

The above-mentioned mixing pressure chamber 2 is made of red copper material.

The above-mentioned external arc heater 1 is a tubular low-enthalpy arc heater, or a segmented medium-enthalpy arc heater, or a laminated high-enthalpy arc heater.

The above-mentioned nozzle 3 is an axisymmetric conical supersonic nozzle or a rectangular supersonic nozzle.

Figure 3 shows the comparison between the method of measuring the airflow enthalpy of the arc heater of the present invention and the traditional equilibrium sound velocity method, and obtained the enthalpy value of the air test medium in the pressure range (0.1-4.5Mpa) and the enthalpy value range (0.5-26MJ/kg). From the measured data, it can be seen that in the entire pressure measurement range, the two methods are in good agreement, which proves the accuracy and effectiveness of the method for measuring the airflow enthalpy of the present invention.

The above are only the preferred embodiments of the present invention and the applied technical principles. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and can also include more other equivalent embodiments without departing from the concept of the present invention. The scope is determined by the scope of the appended claims.

Claims (8)

1. an arc heater airflow enthalpy value rapid measurement system, it is characterized in that: comprise mixing pressure-stabilizing chamber (2), pressure sensor (4) and enthalpy value real-time measuring unit (5); Mixing pressure-stabilizing chamber (2) will The hot air flow generated by the external arc heater (1) is mixed with another part of the cold air flow, the air flow is adjusted and the pressure is stabilized, and the mixed air flow is expanded and accelerated by the external nozzle (3) to form a supersonic airflow at the nozzle (3) outlet; The pressure sensor (4) measures the pressure in the mixing stabilizing chamber (2), and respectively measures the _hot state pressure Phot when the external arc heater (1) is working and the _cold state pressure Pcool when the external arc heater (1) is not working. , and output the two pressure values to the enthalpy real-time measurement unit (5); the enthalpy real-time measurement unit (5) is based on the mass flow conservation during the operation of the arc heater, and uses the two pressures of P _hot and P _cold to evaluate the external arc heating _{The total enthalpy of the airflow is measured according to the total airflow temperature T heat and the pressure P heat obtained when} the device (1) is working; the external arc heater (1) is determined by the enthalpy real-time measurement unit (5). The airflow enthalpy method is as follows: 1) Calculate the airflow flow of the arc heater:

where γ and M are the specific heat ratio and molar mass of the gas in the mixed pressure chamber (2), respectively, R ₀ is the universal gas constant, and under the condition of thermal equilibrium, γ and M are the gas temperature in the mixed pressure chamber (2). and a function of pressure;

It is expressed as a function of temperature and pressure f(T, P), where P and T represent the pressure and temperature of the gas in the mixing plenum (2), respectively, and A ^* is the throat area of the external nozzle (3); 2) According to the mass conservation of the mass flow rate in the hot state when the external arc heater (1) is working and the flow rate in the cold state when it is not working, the total gas temperature in the mixing pressure chamber (2) is obtained:

Wherein T _cool and P _cool are the _temperature and pressure of the gas when the external arc heater (1) is not working, and T and P are the _temperature and pressure of the gas when the external arc heater (1) is working; 3) Based on the total gas temperature in the above-mentioned mixing plenum (2), iterative calculation is used, assuming that the first iteration f(T _hot , P _hot ) ₁ = f(T _cold , P _cold ), according to the mixed plenum ( 2) The measured pressure P _hot and pressure P _cold , obtain the total airflow temperature T _{hot 1} of the mixing plenum (2), and the subscript 1 represents the first iteration; 4) Based on obtaining the initial value of the total gas temperature in the mixing plenum (2), iterative calculation is performed to obtain the final total airflow temperature T _heat in the mixing plenum (2), and the specific method is: Based on the calculated total airflow temperature T _{heat 1} and pressure P _heat , calculate new γ ₂ , M ₂ , and the subscript 2 represents the second iteration, and then obtain f(T _heat , P _heat ) ₂ and the total airflow temperature T _{heat 2} ; and start to iterate, when the total airflow temperature T _{heat N} - the total airflow temperature T _{heat N-1} converges, the iteration ends, and the total airflow temperature T _{heat N} is the final total airflow temperature of the gas in the mixing plenum (2). T _{is hot} ; otherwise, continue the iterative calculation; the subscript N represents the Nth iteration, N≥2; 5) According to the total temperature T _heat and P _heat of the final gas flow in the mixing pressure chamber (2) obtained above, based on the relationship between the gas flow enthalpy value and the temperature and pressure in the thermodynamic equilibrium high temperature gas parameter relationship: H=H(T,P ) to obtain the airflow enthalpy value H of the external arc heater (1). 2 . The rapid measurement system for the gas flow enthalpy value of an arc heater according to claim 1 , wherein the gas flow enthalpy value H in the thermodynamic equilibrium high temperature gas parameter relationship is obtained by using NASA thermochemical equilibrium calculation. 3 . 3 . The rapid measurement system for the enthalpy of gas flow of an arc heater according to claim 1 , wherein the function f(T, P) of the temperature and pressure is obtained by using NASA thermochemical equilibrium calculation. 4 . 4. a kind of electric arc heater gas flow enthalpy value rapid measurement system according to claim 1, is characterized in that: described _T is the temperature of gas when external arc heater (1) is not working, adopts thermometer or K-type thermoelectric even for accurate measurements. 5. A kind of electric arc heater airflow enthalpy value rapid measurement system according to claim 1, is characterized in that: described pressure sensor (4) is strain type pressure sensor, and the measuring range is 0-1MPa or 0-2MPa or 0- 15MPa. 6 . The rapid measurement system for the air flow enthalpy value of an arc heater according to claim 1 , wherein the mixed pressure stabilization chamber ( 2 ) is made of red copper material. 7 . 7. A kind of electric arc heater airflow enthalpy value rapid measurement system according to claim 1, it is characterized in that: described external arc heater (1) is tubular low-enthalpy arc heater, or segmented mid-enthalpy arc heater heaters, or laminated high-enthalpy arc heaters. 8 . The rapid measurement system for the air flow enthalpy of an arc heater according to claim 1 , wherein the nozzle ( 3 ) is an axisymmetric conical supersonic nozzle or a rectangular supersonic nozzle. 9 .

Images