CN110296765A - A kind of extraordinary non-homogeneous electrical heating elements of total temperature field measurement formula and manufacturing method - Google Patents

Abstract

A kind of extraordinary non-homogeneous electrical heating elements of total temperature field measurement formula, including sequentially connected nickel stick, heating tube, nickel tube and copper pipe, temperature element group is provided in the heating tube, and the temperature element group sequentially passes through the nickel tube and the through-hole, the temperature element group includes that several are axially arranged and in the high-temperature resistant optical fiber temperature sensor and a coaxial high-temperature resistant optical fiber temperature sensor of even circumferential distribution along heating tube, the coaxial high-temperature resistant optical fiber temperature sensor is the shaft core position that the heating tube is arranged in, it mutually insulate between the high-temperature resistant optical fiber temperature sensor and between the high-temperature resistant optical fiber temperature sensor and the coaxial high-temperature resistant optical fiber temperature sensor.The present invention provides a kind of extraordinary non-homogeneous electrical heating elements of total temperature field measurement formula, and measurement accuracy and reliability are higher, and the service life is longer.

Description

A full temperature field measurement type special non-uniform electric heating element and its manufacturing method

【Technical field】

The invention relates to an electric heating element, in particular to a full temperature field measuring special non-uniform electric heating element and a manufacturing method.

【Background technique】

In the field of fuel assemblies in the nuclear industry, nuclear reactor fuel assemblies are one of the key components of nuclear reactors, and fuel assemblies are the first barrier to prevent leakage of nuclear fuel and fission products. After the reactor is built and put into operation, the consumption and replacement of fuel assemblies takes up a considerable part of the operating cost of the nuclear reactor. All countries in the world attach great importance to the research and development of advanced fuel assemblies.

According to the different heating temperature distribution methods of electric heating elements, special electric heating elements include uniform electric heating elements and non-uniform electric heating elements. At present, the temperature measuring element of the special electric heating element used by various research institutions is an armored thermocouple, which is prone to breakdown failure in a strong electromagnetic environment, and causes the entire element to be scrapped, so the material life is short, the loss rate is large, and The diameter of the armored thermocouple is large, and a maximum of 7 special electric heating elements can be arranged to obtain the temperature of 7 measuring points. It is difficult to keep the distance between the 7 measuring points and the heating pipe wall, and a certain In addition, the lower conductive nickel-plated copper tube of the special electric heating element adopts the "deep hole small gap nickel, copper rod silver brazing" process, which is technically difficult and has a low yield. The effective contact area between the copper tube and the nickel tube is difficult to exceed 50%, resulting in large contact resistance and easy burning.

【Content of invention】

In order to solve the deficiencies in the prior art, the present invention provides a full temperature field measurement type special non-uniform electric heating element and its manufacturing method, which have higher measurement accuracy and reliability and longer service life.

In order to achieve the above object, the specific scheme adopted by the present invention is:

A special non-uniform electric heating element with full temperature field measurement, including nickel rods, heating tubes, nickel tubes and copper tubes connected in sequence, the heating tube is provided with a temperature measuring element group, and the temperature measuring element group passes through the nickel The tube and the copper tube are characterized in that: the temperature measuring element group includes several high-temperature-resistant optical fiber temperature sensors arranged axially along the heating tube and evenly distributed on the circumference, and a coaxial high-temperature-resistant optical fiber temperature sensor, and the coaxial high-temperature-resistant optical fiber temperature sensor The temperature sensor is arranged at the axial center of the heating tube, and the high temperature resistant optical fiber temperature sensors and the high temperature resistant optical fiber temperature sensor and the coaxial high temperature resistant optical fiber temperature sensor are all insulated from each other.

Preferably, the heating tube has an ultra-slender aspect ratio, and the wall thickness of the heating tube is continuously variable.

Preferably, several insulators are arranged uniformly along the axial direction inside the heating tube, and the temperature measuring element group is fixedly arranged on the insulators.

Preferably, the material of the insulator is ceramic.

Preferably, the number of high-temperature-resistant optical fiber temperature sensors arranged axially along the heating tube and evenly distributed on the circumference can be set to 4-32 as required.

Preferably, the high-temperature-resistant optical fiber temperature sensors arranged axially along the heating tube and evenly distributed on the circumference are arranged in close contact with the inner wall of the heating tube without leaving any gaps.

Preferably, the insulator is cylindrical, the outer wall of the insulator is attached to the inner wall of the heating pipe, and the high temperature resistant optical fiber temperature sensors pass through the insulator.

Preferably, the material of the heating pipe is nickel-based alloy or austenitic stainless steel.

Preferably, the probe diameter of the high temperature resistant optical fiber temperature sensor and the coaxial high temperature resistant optical fiber temperature sensor can be set to 0.2 mm to 0.4 mm, and the fiber diameter can be set to 0.1 mm to 0.2 mm.

A method for manufacturing a special non-uniform electric heating element with full temperature field measurement, comprising the following steps:

S1. Select a nickel-based alloy or austenitic stainless steel pipe with an inner diameter from 5.4mm to 8.7mm that changes continuously according to the design requirements and an outer diameter of 9.5mm as the heating pipe;

S2. Place the high-temperature-resistant optical fiber temperature sensor and the coaxial high-temperature-resistant optical fiber temperature sensor arranged axially along the heating tube and evenly distributed on the circumference in the segmented insulator according to the design requirements;

S3. Insert the ceramic insulator with the optical fiber temperature sensor into the heating tube;

S4. Completely butt the heating tube with the nickel rod, and use resistance butt welding technology to weld;

S5, the heating tube is completely docked with the nickel tube;

S6, make complete contact between the nickel tube and the copper tube through adjustment;

S7. Completely connect the two parts of S4 and S5.

When the present invention is in use, a single coaxial high-temperature-resistant optical fiber temperature sensor is used to measure the temperature of the central measuring point of the heating tube, and a plurality of high-temperature-resistant optical fiber temperature sensors evenly arranged close to the inner wall of the heating tube can obtain the radial temperature of the heating tube. The temperature field in the circumferential direction of any section; the coaxial high temperature resistant optical fiber temperature sensor provides a reference temperature with high precision and fast response to temperature changes. Combined with the sensing data of the high temperature resistant fiber optic sensor, accurate temperature measurement results can be obtained. Moreover, the present invention adopts a high-temperature resistant optical fiber temperature sensor and a coaxial high-temperature resistant optical fiber temperature sensor. The optical fiber is an insulator, and the strong electromagnetic environment has no effect on its performance. Compared with the existing armored thermocouple electric heating element, it can effectively avoid Breakdown occurs in a strong electromagnetic environment, the measurement accuracy and reliability are higher, and the service life is longer.

【Description of drawings】

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the overall structural representation of the present invention;

Fig. 2 is a transverse sectional view of a heating tube of the present invention;

Fig. 3 is a longitudinal sectional view of the heating tube of the present invention.

Reference signs: 1-nickel rod, 2-heating tube, 3-nickel tube, 4-copper tube, 5-insulator, 6-temperature measuring element group, 7-high temperature resistant optical fiber temperature sensor, 8-coaxial high temperature resistant optical fiber Temperature Sensor

【Detailed ways】

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

When the present invention is in use, according to production needs, it can be made into two types of electric heating elements, uniform and non-uniform. Correspondingly, it is only necessary to change the high-temperature-resistant optical fiber temperature sensor 7 arranged axially along the heating tube 2 and evenly distributed on the circumference. and the distribution mode of the coaxial high temperature resistant optical fiber temperature sensor 8, the coaxial high temperature resistant optical fiber temperature sensor 8 is arranged at the axial center of the heating tube 2, the high temperature resistant optical fiber temperature sensor 7 and the coaxial high temperature resistant optical fiber temperature sensor 8 are essentially the same A kind of optical fiber temperature sensor, but in the present invention because of the difference of arrangement position.

In this embodiment, it is a non-uniform electric heating element, please refer to Figures 1 and 2, Figure 1 is a schematic diagram of the overall structure of the present invention, Figure 2 is a transverse cross-sectional view of the temperature measuring element of the present invention, and Figure 3 is a schematic diagram of the present invention Longitudinal cross-section of the heating tube.

A special non-uniform electric heating element with full temperature field measurement, including nickel rod 1, heating tube 2, nickel tube 3 and copper tube 4 connected in sequence. The group 6 passes through the nickel tube 3 and the copper tube 4 in turn, and the temperature measuring element group 6 includes several high-temperature-resistant optical fiber temperature sensors 7 arranged axially along the heating tube 2 and uniformly distributed on the circumference and a coaxial high-temperature-resistant optical fiber temperature sensor 8 , more precisely, the coaxial high temperature resistant optical fiber temperature sensor 8 is arranged at the axial center of the heating tube 2, the high temperature resistant optical fiber temperature sensors 7 are insulated from each other, the high temperature resistant optical fiber temperature sensor 7 and the coaxial high temperature resistant optical fiber temperature The sensors 8 are insulated from each other.

Further, the diameter of the nickel rod 1 , the outer diameter of the heating tube 2 and the outer diameter of the nickel tube 3 are equal and smaller than the outer diameter of the copper tube 4 . In order to make the outer dimension of the electric heating element the same as that of the nuclear fuel rod, the accuracy of the experimental result is improved.

When the present invention is in use, the high-temperature-resistant optical fiber temperature sensor 7 senses the temperature in multiple directions on the inner wall of the heating tube 2, and the coaxial high-temperature-resistant optical fiber temperature sensor 8 provides a reference temperature with high precision and fast response to temperature changes. Accurate heating results can be obtained by combining the sensing data of the sensor 7 with the sensing data of the coaxial high temperature resistant optical fiber temperature sensor 8 . Moreover, the present invention adopts a high-temperature-resistant optical fiber temperature sensor 7 and a coaxial high-temperature-resistant optical fiber temperature sensor 8. The optical fiber is an insulator, and the strong electromagnetic environment has no effect on its performance. It is especially suitable for environments with strong electromagnetic fields, such as nuclear power environments. Compared with some armored thermocouple electric heating elements, it can effectively avoid the problem of breakdown in a strong electromagnetic environment, and the measurement accuracy, reliability and service life are longer.

Further, an insulator 5 is evenly arranged inside the heating tube 2 , and the temperature measuring element group 6 is fixedly arranged on the insulator 5 . The insulator 5 can ensure the insulation performance between the high temperature resistant optical fiber temperature sensor 7 and between the high temperature resistant optical fiber temperature sensor 7 and the coaxial high temperature resistant optical fiber temperature sensor 8, and can control the temperature of the high temperature resistant optical fiber temperature sensor 7 and the coaxial high temperature resistant optical fiber temperature sensor. The sensor 8 is reinforced. In this embodiment, the material of the insulator 5 is set to be ceramics, and in other embodiments, it can also be replaced with other materials with similar properties.

In addition, in this embodiment, eight high-temperature-resistant optical fiber temperature sensors 7 are arranged at 0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315°, and are evenly distributed in the heating The inner wall of the tube 2 can directly obtain the actual temperatures of the eight circumferential directions of the inner wall of the heating tube 2 . In other embodiments, 4 to 32 high-temperature-resistant optical fiber temperature sensors 7 can be arranged according to the temperature detection requirements, or even arranged along the circumference in a non-uniform manner according to the design of the inner wall of the heating tube 2 .

Further, since the high-temperature-resistant optical fiber temperature sensor 7 is used, the high-temperature-resistant optical fiber temperature sensor 7 can be completely attached to the inner wall of the heating tube 2 in the best state during installation, or it can be arranged at a distance from the heating tube 2. The position of the inner wall is less than 0.2mm, so that the temperature of the inner wall of the heating tube 2 can be obtained more accurately. The high temperature resistant optical fiber temperature sensor 7 is an insulator, and the performance of the high temperature resistant optical fiber temperature sensor 7 will not be affected in a strong electromagnetic environment. 7 It can work normally in a strong electromagnetic environment.

Further, the outer periphery of the insulator 5 is attached to the inner wall of the heating pipe 2 , and the high temperature resistant optical fiber temperature sensor 7 and the coaxial high temperature resistant optical fiber temperature sensor 8 are both penetrated through the insulator 5 . Correspondingly, eight first through holes corresponding to the high temperature resistant optical fiber temperature sensor 7 and a second through hole corresponding to a coaxial high temperature resistant optical fiber temperature sensor 8 are opened on the insulator 5, the first through hole and the second through hole The two through holes both extend along the axial direction of the insulator 5 .

Further, the material of the heating tube 2 is nickel-based alloy or austenitic stainless steel; the outer diameter of the heating tube 2 is 9.5 mm, and the length is usually between 1.5 m and 5.0 m; the inner wall of the heating tube 2 is continuously changing, and in this implementation In the example, the change of the inner wall of the heating tube 2 conforms to the truncated cosine curve, so the wall thickness of the heating tube 2 shows a continuous change, which can achieve a specific non-uniform heating effect. In other embodiments, the shape curve of the inner wall of the heating tube 2 can also be changed according to the requirements to set.

In this embodiment, the probe diameters of the high temperature resistant optical fiber temperature sensor 7 and the coaxial high temperature resistant optical fiber temperature sensor 8 can be 0.2 mm to 0.4 mm, and the diameter of the optical fiber can be set to 0.1 mm to 0.2 mm. With the smaller size of the optical fiber temperature sensor, the present invention can more conveniently arrange the overall arrangement of the temperature measurement points. In other words, because the optical fiber temperature sensor is smaller in size, more optical fibers can be arranged in the limited space on the inner wall of the heating tube 2 The temperature sensor means that more temperature measurement points can be obtained, and more abundant temperature measurement data can be obtained.

The assembly method of the present invention is as follows.

S1. Select an ultra-slender nickel-based alloy or austenitic stainless steel pipe with an inner diameter ranging from 5.4mm to 8.7mm continuously according to design requirements and an outer diameter of 9.5mm as the heating pipe 2 .

S2. Place the high temperature resistant optical fiber temperature sensor 7 and the coaxial high temperature resistant optical fiber temperature sensor 8 in the segmented insulator 5 according to design requirements.

S3 , inserting the ceramic insulator 5 with the optical fiber temperature sensor placed into the heating tube 2 .

S4. Completely butt joint the heating tube 2 with the nickel rod 1, and perform welding by resistance butt welding technology.

S5. Completely connect the heating tube 2 with the nickel tube 3 .

S6. Making the nickel tube 3 and the copper tube 4 completely contact each other through adjustment.

S7. Completely connect the two parts of S4 and S5.

In the above assembly method, the transition section of the heating tube 2 and the copper tube 4 adopts a special molding process of continuous balanced extrusion, which simplifies the manufacturing process and improves the reliability of the product.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A special non-uniform electric heating element with full temperature field measurement, comprising nickel rods (1), heating tubes (2), nickel tubes (3) and copper tubes (4) connected in sequence, the heating tubes (2 ) is provided with a temperature measuring element group (6), and the temperature measuring element group (6) passes through the nickel tube (3) and the copper tube (4) in sequence, characterized in that: the temperature measuring element The group (6) includes several high temperature resistant optical fiber temperature sensors (7) arranged axially along the heating tube (2) and evenly distributed on the circumference and a coaxial high temperature resistant optical fiber temperature sensor (8), the high temperature resistant optical fiber temperature sensor (7) and between the high temperature resistant optical fiber temperature sensor (7) and the coaxial high temperature resistant optical fiber temperature sensor (8) are insulated from each other. 2. A special non-uniform electric heating element with full temperature field measurement as claimed in claim 1, characterized in that: the heating tube (2) has an ultra-slender length ratio, and the wall thickness of the heating tube (2) is is continuously changing. 3. A special non-uniform electric heating element with full temperature field measurement as claimed in claim 2, characterized in that: the heating tube (2) is provided with several insulators (5) uniformly arranged along the axial direction, The temperature measuring element group (6) is fixedly arranged on the insulator (5). 4. The full temperature field measuring special non-uniform electric heating element according to claim 3, characterized in that: the material of the insulator (5) is ceramic. 5. A special non-uniform electric heating element with full temperature field measurement as claimed in claim 3, characterized in that: the number of high temperature resistant optical fiber temperature sensors (7) can be set to 4-32 as required. 6. A special non-uniform electric heating element with full temperature field measurement as claimed in claim 5, characterized in that: the high temperature resistant optical fiber temperature sensor (7) is arranged completely close to the inner wall of the heating tube (2), Leave no gaps. 7. A special non-uniform electric heating element with full temperature field measurement as claimed in claim 4, characterized in that: the insulator (5) is cylindrical, and the outer wall of the insulator (5) is in contact with the heating tube The inner walls of (2) are attached to each other, and the high temperature resistant optical fiber temperature sensor (7) and the coaxial high temperature resistant optical fiber temperature sensor (8) both pass through the insulator (5). 8. A special non-uniform electric heating element with full temperature field measurement as claimed in claim 1, characterized in that: said heating tube (2) is made of nickel-based alloy or austenitic stainless steel. 9. A full temperature field measurement type special non-uniform electric heating element as claimed in claim 1, characterized in that: the high temperature resistant optical fiber temperature sensor (7) and the coaxial high temperature resistant optical fiber temperature sensor (8) The diameter of the probe can be set from 0.2mm to 0.4mm, and the diameter of the fiber can be set from 0.1mm to 0.2mm. 10. A method for manufacturing a full temperature field measurement type special non-uniform electric heating element as described in any of claims 1 to 9, characterized in that it includes the following steps: S1. Select a nickel-based alloy or austenitic stainless steel pipe with an inner diameter continuously changing from 5.4mm to 8.7mm and an outer diameter of 9.5mm as the heating tube (2); S2. Place the high temperature resistant optical fiber temperature sensor (7) and the coaxial high temperature resistant optical fiber temperature sensor (8) in the segmented insulator (5) according to the design requirements; S3. Insert the ceramic insulator (5) with the optical fiber temperature sensor into the heating tube (2); S4, the heating tube (2) is completely docked with the nickel rod (1); S5, the heating tube (2) is completely docked with the nickel tube (3); S6, make complete contact between the nickel tube (3) and the copper tube (4) by adjustment; S7. Completely connect the two parts of S4 and S5.