Temperature measurement experimental device and experimental method for special-shaped heat exchange tube

Abstract

The invention provides a temperature measurement experimental device and experimental method for a special-shaped heat exchange tube, and belongs to the field of temperature measurement of special-shaped heat exchange tubes. The problems that an existing special-shaped heat exchange tube flow heat exchange characteristic experiment device is inconvenient in temperature measurement and low in accuracy are solved. The temperature measurement experiment device comprises a first fiber bragg grating temperature sensor, a second fiber bragg grating temperature sensor and pneumatic spring supports, and the first fiber bragg grating temperature sensor is arranged in the center of the interior of the special-shaped heat exchange tube in the axial direction through a plurality of pneumatic spring supports; the second fiber bragg grating temperature sensor is pasted on the outer surface of the first fiber bragg grating temperature sensor in the axial direction, and a plurality of grating measuring points are arranged on the first fiber bragg grating temperature sensor and the second fiber bragg grating temperature sensor in the length direction. The first fiber bragg grating temperature sensor and the second fiber bragg grating temperature sensor are connected with a data acquisition system. The device is mainly used for the temperature measurement experiment of the special-shaped heat exchange tube.

Description

Technical Field

[0001] The present invention belongs to the technical field of temperature measurement of special-shaped heat exchange tubes, and particularly relates to a temperature measurement experimental device and an experimental method for special-shaped heat exchange tubes. Background Technique

[0002] With the continuous development of nuclear energy technology, reactors are gradually developing towards miniaturization, high energy density, and high safety. In order to ensure the safety of reactors, optimizing the structure of in-core heat exchangers to enhance the heat transfer capacity has become one of the main measures for current development. Special-shaped heat exchange tubes are a new type of heat exchanger that enhances its own heat transfer capacity by optimizing the structure of the heat exchanger, and have the following advantages compared with traditional heat exchangers: (1) high heat transfer efficiency; (2) large heat transfer area; (3) space saving; (4) improved fluid distribution uniformity.

[0003] The flow and heat transfer characteristics of special-shaped heat exchange tubes consist of two parts: the heat transfer characteristics outside the tube and the heat transfer characteristics inside the tube. Therefore, it is very necessary to measure the temperature of the outer wall surface of the heat exchange tube and the temperature of the fluid inside the tube for the study of the flow and heat transfer characteristics of the heat exchanger itself.

[0004] Special-shaped heat exchange tubes have the following difficulties in measuring the temperature distribution of the fluid inside the tube due to their complex geometric structure: (1) When measuring the temperature of the fluid inside the special-shaped heat exchange tube, if a multi-point thermocouple is used, it is difficult for the multi-point thermocouple to pass through the inside of the special-shaped heat exchange tube due to the relatively large size of the thermocouple itself and the relatively small size of the special-shaped heat exchange tube. (2) After the multi-point thermocouple is installed inside the special-shaped heat exchange tube, its own size will cause a large interference to the internal flow field, thus affecting the accuracy of the flow and heat transfer characteristics; (3) In the existing measurement methods, the measuring element cannot be fixed at the central position of the special-shaped heat exchange tube, and the fluid inside the special-shaped heat exchange tube makes the measuring element in a shaking state, resulting in a large error in temperature measurement. Summary of the Invention

[0005] In view of this, the present invention aims to propose a temperature measurement experimental device and an experimental method for special-shaped heat exchange tubes to solve the problems of inconvenient temperature measurement and low accuracy of the existing experimental device for the flow and heat transfer characteristics of special-shaped heat exchange tubes.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A temperature measurement experimental device for a special-shaped heat exchange tube, which includes a first fiber Bragg grating temperature sensor, a second fiber Bragg grating temperature sensor, and a pneumatic spring support. The first fiber Bragg grating temperature sensor is axially arranged at the inner center position of the special-shaped heat exchange tube through a plurality of pneumatic spring supports. The second fiber Bragg grating temperature sensor is axially pasted on the outer surface of the second fiber Bragg grating temperature sensor. A number of grating measurement points are arranged along the length direction on both the first fiber Bragg grating temperature sensor and the second fiber Bragg grating temperature sensor. Both the first fiber Bragg grating temperature sensor and the second fiber Bragg grating temperature sensor are connected to a data acquisition system. The pneumatic spring support includes a telescopic air cushion and an elastic force component. The inner ring of the telescopic air cushion clamps the first fiber Bragg grating temperature sensor. A plurality of elastic force components are evenly distributed along the circumferential direction on the outer ring of the telescopic air cushion. The elastic force components are connected to the inner wall of the special-shaped heat exchange tube. The telescopic air cushion is connected to an air supply pipe, and the air supply pipe is connected to an air supply device. The inlet end of the special-shaped heat exchange tube is connected to a first four-way joint, and the outlet end of the special-shaped heat exchange tube is connected to a second four-way joint. The first four-way joint is connected to an inlet pipe, and the second four-way joint is connected to an outlet pipe. Both the inlet pipe and the outlet pipe are connected to the special-shaped heat exchange tube.

[0007] Furthermore, a differential pressure sensor is connected between the first four-way joint and the second four-way joint through a pneumatic pipe, and the differential pressure sensor is connected to the data acquisition system.

[0008] Furthermore, the elastic force component includes a spring, a spring lower support, and a spring upper support. The two ends of the spring are respectively connected to the spring lower support and the spring upper support. The spring lower support is connected to the telescopic air cushion, and the spring upper support is connected to the inner wall of the special-shaped heat exchange tube.

[0009] Furthermore, the air supply pipe and the tail end of the first fiber Bragg grating temperature sensor pass through the upper part of the first four-way joint through a fiber optic lead-out device.

[0010] Furthermore, the inlet pipe is connected to a first regulating valve, and the outlet pipe is connected to a second regulating valve.

[0011] Furthermore, pneumatic spring supports are arranged on both the straight section and the bent section of the special-shaped heat exchange tube.

[0012] Furthermore, the grating measurement points on the first fiber Bragg grating temperature sensor and the second fiber Bragg grating temperature sensor are arranged correspondingly, and the grating measurement points at the corresponding positions are at the same horizontal height.

[0013] Furthermore, the materials of the spring lower support and the spring upper support are titanium, aluminum alloy or magnesium alloy.

[0014] Furthermore, the first four-way joint, the second four-way joint, the inlet pipeline and the outlet pipeline are all made of stainless steel.

[0015] The present invention also provides an experimental method for a temperature measurement experimental device for a special-shaped heat exchange tube, specifically as follows: The fluid enters the interior of the special-shaped heat exchange tube through the inlet pipeline, flows through the special-shaped heat exchange tube, and then flows out of the test section through the outlet pipeline. During this process, the first fiber Bragg grating temperature sensor measures the temperature distribution of the fluid inside the special-shaped heat exchange tube, and the second fiber Bragg grating temperature sensor is adjusted to measure the temperature distribution of the outer wall surface of the special-shaped heat exchange tube. The distance between the grating measurement points on the first fiber Bragg grating temperature sensor and the second fiber Bragg grating temperature sensor can realize the measurement of the outer wall surface temperature and the fluid temperature inside the tube at different positions, and is collected and analyzed through a data acquisition system, so as to carry out experimental research on the flow and heat transfer characteristics of the special-shaped heat exchange tube.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention proposes a temperature measurement experimental device and an experimental method for a special-shaped heat exchange tube. Through the scheme described in the present invention, the specific distribution of the fluid temperature inside the special-shaped heat exchange tube and the temperature of the outer wall surface of the tube can be mastered, which is convenient for carrying out research on the flow and heat transfer characteristics of the special-shaped heat exchange tube.

[0017] The present invention uses a fiber Bragg grating temperature sensor as a temperature measurement element. The size of the fiber Bragg grating temperature sensor is less than 1 mm, and multiple grating temperature measurement points can be set. It is convenient to install and has a small installation error. Therefore, the problem of difficult installation caused by size reasons can be solved. Moreover, due to the small size of the fiber Bragg grating temperature sensor used in the present invention, it basically does not interfere with the flow field, ensuring the accuracy of the research on the flow and heat transfer characteristics.

[0018] The present invention fixes pneumatic spring supports at multiple positions inside the special-shaped heat exchange tube. The pneumatic spring support drives the external spring support to be fixed inside the pipeline through the expansion of the air space, and at the same time can tighten the central area so that the fiber Bragg grating temperature sensor can be effectively fixed at the central position of the special-shaped heat exchange tube, solving the problem of shaking caused by the inability to fix the sensor, thereby avoiding temperature measurement errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0020] Figure 1 is a schematic structural diagram of a temperature measurement experimental device for a special-shaped heat exchange tube according to the present invention;

[0021] Figure 2 is a schematic structural diagram of the pneumatic spring support according to the present invention.

[0022] In the figure:

[0023] 1 - Gas supply device, 2 - Gas supply pipe, 3 - First fiber Bragg grating temperature sensor, 4 - Data acquisition system, 5 - Fiber optic lead-out device, 6 - First four-way joint, 7 - Inlet pipe, 8 - First regulating valve, 9 - Differential pressure sensor, 10 - Special-shaped heat exchange tube, 11 - Grating measurement point, 12 - Pneumatic spring support, 13 - Second four-way joint, 14 - Outlet pipe, 15 - Second regulating valve, 16 - Telescopic air cushion, 17 - Spring lower support, 18 - Spring, 19 - Spring upper support, 20 - Second fiber Bragg grating temperature sensor Specific implementation mode

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0025] See Figure 1-2 Describing this embodiment, a temperature measurement experimental device for a special-shaped heat exchange tube, which includes a first fiber Bragg grating temperature sensor 3, a second fiber Bragg grating temperature sensor 20 and a pneumatic spring support 12. The first fiber Bragg grating temperature sensor 3 is axially arranged at the inner center position of the special-shaped heat exchange tube 10 through a plurality of pneumatic spring supports 12. The second fiber Bragg grating temperature sensor 20 is axially pasted on the outer surface of the second fiber Bragg grating temperature sensor 20 through high-temperature resistant glue. A plurality of grating measurement points 11 are arranged along the length direction on both the first fiber Bragg grating temperature sensor 3 and the second fiber Bragg grating temperature sensor 20. Both the first fiber Bragg grating temperature sensor 3 and the second fiber Bragg grating temperature sensor 20 are connected to the data acquisition system 4. The pneumatic spring support 12 includes a telescopic air cushion 16 and an elastic component. The first fiber Bragg grating temperature sensor 3 is placed in the central part of the telescopic air cushion 16. The inner ring of the telescopic air cushion 16 clamps the first fiber Bragg grating temperature sensor 3. A plurality of elastic components are evenly distributed along the circumferential direction on the outer ring of the telescopic air cushion 16. The number of elastic components is preferably three. The elastic components are connected to the inner wall of the special-shaped heat exchange tube 10. The telescopic air cushion 16 is connected to the gas supply pipe 2. The gas supply pipe 2 is connected to the gas supply device 1. The inlet end of the special-shaped heat exchange tube 10 is screwed and connected to the first four-way joint 6. The outlet end of the special-shaped heat exchange tube 10 is screwed and connected to the second four-way joint 13. The first four-way joint 6 is screwed and connected to the inlet pipe 7. The second four-way joint 13 is screwed and connected to the outlet pipe 14. Both the inlet pipe 7 and the outlet pipe 14 are communicated with the special-shaped heat exchange tube 10.

[0026] In this embodiment, a differential pressure sensor 9 is connected between the first four-way joint 6 and the second four-way joint 13 through a pneumatic tube. The differential pressure sensor 9 is connected to the data acquisition system 4. The differential pressure sensor 9 is used to measure the differential pressure inside the special-shaped heat exchange tube 10. The differential pressure sensor 9 can select different range values according to the experimental conditions.

[0027] In this embodiment, the elastic component includes a spring 18, a spring lower bracket 17, and a spring upper bracket 19. The two ends of the spring 18 are respectively connected to the spring lower bracket 17 and the spring upper bracket 19 by welding. The spring lower bracket 17 is connected to the telescopic air cushion 16 by pasting. The spring upper bracket 19 is connected to the inner wall of the special-shaped heat exchange tube 10. The size of the spring upper bracket 19 can be adjusted according to the inner diameter size of the special-shaped heat exchange tube 10, and the size of the telescopic air cushion 16 can be adjusted according to the outer diameter size of the first fiber Bragg grating temperature sensor 3 at the central position. The materials of the spring lower bracket 17 and the spring upper bracket 19 are materials with high toughness and light weight, preferably titanium, aluminum alloy or magnesium alloy.

[0028] In this embodiment, the tail ends of the air supply pipe 2 and the first fiber Bragg grating temperature sensor 3 pass through the upper part of the first four-way joint 6 through a fiber optic lead-out device 5.

[0029] In this embodiment, the inlet pipe 7 is connected to the first regulating valve 8 by a flange, and the outlet pipe 14 is connected to the second regulating valve 15 by a flange. The flow rate at the inlet is adjusted by the first regulating valve 8, and the flow rate at the outlet is adjusted by the second regulating valve 15.

[0030] In this embodiment, pneumatic spring brackets 12 are provided on both the straight section and the bent section of the special-shaped heat exchange tube 10. The lengths of the first fiber Bragg grating temperature sensor 3 and the second fiber Bragg grating temperature sensor 20 are the same as the length of the special-shaped heat exchange tube. The grating measuring points 11 on the first fiber Bragg grating temperature sensor 3 and the second fiber Bragg grating temperature sensor 20 are correspondingly arranged, and the grating measuring points 11 at the corresponding positions are at the same horizontal height. The materials of the first four-way joint 6, the second four-way joint 13, the inlet pipe 7 and the outlet pipe 14 are all stainless steel. The joint sizes of the first four-way joint 6 and the second four-way joint 13 can be adjusted according to parameters such as the size of the connected special-shaped heat exchange tube 10, the sizes of the inlet pipe 7 and the outlet pipe 14.

[0031] This embodiment is an experimental method for an experimental device for measuring the temperature of a special-shaped heat exchange tube, specifically: The first regulating valve 8 and the inlet pipe 7 are connected by a flange, and the inlet pipe 7, the first four-way joint 6 and the inlet of the special-shaped heat exchange tube 10 are connected by screwing the joints tightly. The first fiber Bragg grating temperature sensor 3 passes through the central position of the pneumatic spring support 12 and is then placed entirely inside the special-shaped heat exchange tube 10. The air supply device 1 supplies air to the telescopic air cushion 16 inside the pneumatic spring support through the air supply pipe 2, so that the spring upper support 19 at different cross-sectional positions is connected and fixed to the inner wall of the special-shaped heat exchange tube 10. At the same time, the tightening of the telescopic air cushion 16 fixes the first fiber Bragg grating temperature sensor 3 at the central position of the special-shaped heat exchange tube 10. The tail ends of the air supply pipe 2 and the first fiber Bragg grating temperature sensor 3 pass through the upper part of the first four-way joint 6 through the optical fiber lead-out device 5. The outlet end of the special-shaped heat exchange tube 10 is connected to the second four-way joint 13 by screwing the joints tightly, the second four-way joint 13 and the outlet pipe 14 are connected by screwing the joints tightly, and the outlet pipe 14 and the second regulating valve 15 are connected by a flange. The second fiber Bragg grating temperature sensor 20 is pasted on the outer surface of the special-shaped heat exchange tube 10 with high-temperature resistant glue, and the differential pressure sensor 9 is connected to the first four-way joint 6 and the second four-way joint 13 respectively through pneumatic pipes. The signals output by the differential pressure sensor 9, the first fiber Bragg grating temperature sensor 3 and the second fiber Bragg grating temperature sensor 20 are collected and analyzed by the data acquisition system 4.

[0032] During the experiment, after the fluid adjusts the flow rate through the first regulating valve 8 and enters the inlet pipe 7, it enters the inside of the special-shaped heat exchange tube 10 through the first four-way joint 6, flows through the special-shaped heat exchange tube 10 and then enters the outlet pipe 14 through the second four-way joint 13, and then flows out of the test section through the second regulating valve 15. During the process, the first fiber Bragg grating temperature sensor 3 measures the temperature distribution of the fluid inside the special-shaped heat exchange tube 10, and the second fiber Bragg grating temperature sensor 20 measures the temperature distribution of the outer wall surface of the special-shaped heat exchange tube 10. By adjusting the distance between the grating measurement points 11 on the first fiber Bragg grating temperature sensor 3 and the second fiber Bragg grating temperature sensor 20, the measurement of the outer wall surface temperature and the fluid temperature inside the tube at different positions can be realized, and the data is collected and analyzed by the data acquisition system 4, so as to carry out experimental research on the flow and heat transfer characteristics of the special-shaped heat exchange tube 10. The special-shaped heat exchange tube 10 can change parameters such as shape, radius, and length according to experimental requirements, and then carry out research on the temperature measurement of the fluid inside the special-shaped heat exchange tube 10 with different structures. The grating measurement points 11 can be adjusted in position and quantity according to experimental needs and are engraved on the first fiber Bragg grating temperature sensor 3 and the second fiber Bragg grating temperature sensor 20 according to experimental requirements.

[0033] The specific embodiments of the present invention disclosed above are only used to help illustrate the present invention. The specific embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. According to the content of this specification, many modifications and variations can be made. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention.

Claims

1. An experimental device for temperature measurement of special-shaped heat exchange tubes, characterized in that: It includes a first fiber Bragg grating temperature sensor (3), a second fiber Bragg grating temperature sensor (20) and a pneumatic spring support (12). The first fiber Bragg grating temperature sensor (3) is axially arranged at the inner center position of the special-shaped heat exchange tube (10) through a plurality of pneumatic spring supports (12). The second fiber Bragg grating temperature sensor (20) is axially pasted on the outer surface of the second fiber Bragg grating temperature sensor (20). A number of grating measuring points (11) are arranged along the length direction on both the first fiber Bragg grating temperature sensor (3) and the second fiber Bragg grating temperature sensor (20). Both the first fiber Bragg grating temperature sensor (3) and the second fiber Bragg grating temperature sensor (20) are connected to a data acquisition system (4). The pneumatic spring support (12) includes a telescopic air cushion (16) and an elastic force component. The inner ring of the telescopic air cushion (16) clamps the first fiber Bragg grating temperature sensor (3). The outer ring of the telescopic air cushion (16) is evenly distributed with a plurality of elastic force components along the circumferential direction. The elastic force components are connected to the inner wall of the special-shaped heat exchange tube (10). The telescopic air cushion (16) is connected to an air supply pipe (2). The air supply pipe (2) is connected to an air supply device (1). The inlet end of the special-shaped heat exchange tube (10) is connected to a first four-way joint (6). The outlet end of the special-shaped heat exchange tube (10) is connected to a second four-way joint (13). The first four-way joint (6) is connected to an inlet pipe (7). The second four-way joint (13) is connected to an outlet pipe (14). Both the inlet pipe (7) and the outlet pipe (14) are communicated with the special-shaped heat exchange tube (10).

2. The temperature measurement experimental device for a special-shaped heat exchange tube according to claim 1, characterized in that: A differential pressure sensor (9) is connected between the first four-way joint (6) and the second four-way joint (13) through a pneumatic pipe. The differential pressure sensor (9) is connected to the data acquisition system (4).

3. The temperature measurement experimental device for special-shaped heat exchange tubes according to claim 1, wherein: The elastic force component includes a spring (18), a spring lower support (17) and a spring upper support (19). The two ends of the spring (18) are respectively connected to the spring lower support (17) and the spring upper support (19). The spring lower support (17) is connected to the telescopic air cushion (16). The spring upper support (19) is connected to the inner wall of the special-shaped heat exchange tube (10).

4. An experimental device for temperature measurement of a special-shaped heat exchange tube according to claim 1, characterized in that: The tail ends of the air supply pipe (2) and the first fiber Bragg grating temperature sensor (3) pass through the upper part of the first four-way joint (6) through a fiber lead-out device (5).

5. An experimental device for temperature measurement of special-shaped heat exchange tubes according to claim 1, characterized in that: The inlet pipe (7) is connected to a first regulating valve (8). The outlet pipe (14) is connected to a second regulating valve (15).

6. The temperature measurement experimental device for a special-shaped heat exchange tube according to claim 1, wherein: Pneumatic spring supports (12) are arranged on both the straight section and the bent section of the special-shaped heat exchange tube (10).

7. An experimental device for temperature measurement of a special-shaped heat exchange tube according to claim 1, characterized in that: The grating measuring points (11) on the first fiber Bragg grating temperature sensor (3) and the second fiber Bragg grating temperature sensor (20) are arranged correspondingly, and the grating measuring points (11) at the corresponding positions are at the same horizontal height.

8. The temperature measurement experimental device for a special-shaped heat exchange tube according to claim 3, characterized in that: The materials of the spring lower support (17) and the spring upper support (19) are titanium, aluminum alloy or magnesium alloy.

9. The temperature measurement experimental device for special-shaped heat exchange tubes according to claim 1, characterized in that: The materials of the first four-way joint (6), the second four-way joint (13), the inlet pipe (7) and the outlet pipe (14) are all stainless steel.

10. An experimental method for the temperature measurement experimental device of the special-shaped heat exchange tube as described in claim 1, characterized in that: The fluid enters the interior of the special-shaped heat exchange tube (10) through the inlet pipe (7), flows through the special-shaped heat exchange tube (10), and then flows out of the test section through the outlet pipe (14). During this process, the first fiber Bragg grating temperature sensor (3) measures the temperature distribution of the fluid inside the special-shaped heat exchange tube (10), and the second fiber Bragg grating temperature sensor (20) measures the temperature distribution of the outer wall surface of the special-shaped heat exchange tube (10). By adjusting the distance between the grating measurement points (11) on the first fiber Bragg grating temperature sensor (3) and the second fiber Bragg grating temperature sensor (20), the measurement of the outer wall surface temperature and the fluid temperature inside the tube at different positions can be realized. The data is collected and analyzed by the data acquisition system (4), so as to carry out experimental research on the flow and heat transfer characteristics of the special-shaped heat exchange tube (10).

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