Heat exchanger performance test system

Abstract

According to the heat exchanger performance test system provided by the utility model, helium is introduced into the vacuum cold box after being pressurized by the compressor, in the vacuum cold box, the hot end of the heat exchanger to be tested is connected with the air supply pipeline and the air return pipeline of the compressor, and the cold end of the heat exchanger to be tested is connected with the air inlet and the air outlet of the red copper coil; an inlet and an outlet of the to-be-tested heat exchanger are respectively provided with a temperature sensor and a pressure sensor, a plurality of temperature sensors are distributed on the surface of the to-be-tested heat exchanger, the temperature sensors can continuously monitor the temperature change of the to-be-tested heat exchanger in real time, and the pressure sensors can dynamically monitor the pressure change of the inlet and the outlet in real time. The measurement and control working platform can acquire temperature data and pressure data of the heat exchanger to be tested through the data acquisition unit, and the test system provided by the utility model can accurately evaluate the heat exchange efficiency of the heat exchanger and the cold storage or heat storage capacity of the wall of the heat exchanger under the conditions of different mass flows and different switching frequencies.

Description

Technical Field

[0001] The utility model relates to the technical field of low-temperature heat exchangers, in particular to a heat exchanger performance testing system. Background Art

[0002] The pulse tube (or piston) expansion refrigerator is a refrigerator that can achieve high reliability operation in the low temperature zone and is suitable for medium-sized cooling demand. The overall performance of the refrigerator is not only determined by the efficiency of the expander, but also greatly depends on the efficient heat exchange capacity of the heat exchanger. Unlike the traditional regenerative refrigerator, which realizes the alternating flow and energy exchange of hot and cold fluids through the regenerator in a single flow channel, the pulse tube (or piston) expansion refrigerator adopts a partition-type heat exchanger design, and the hot and cold fluids need to be effectively exchanged in an intermittent flow state.

[0003] The current heat exchanger testing systems mainly include two categories. One is to test the heat transfer performance of the partition wall heat exchanger under continuous flow conditions, and the other is to test the heat transfer performance of the traditional cold (heat) storage device under intermittent flow conditions when the cold and hot fluids flow through the same channel of the heat exchanger. There is no special test of the heat transfer performance of the partition wall heat exchanger in the pulse tube (or piston) expansion refrigerator under intermittent flow conditions. Utility Model Content

[0004] In view of this, it is necessary to provide a heat exchanger performance testing system that can test the heat exchange performance of a partition-type heat exchanger to address the current technical defect that there is no heat exchange performance test specifically for a partition-type heat exchanger under intermittent flow conditions.

[0005] In order to solve the above problems, the utility model adopts the following technical solutions:

[0006] One of the purposes of the utility model is to provide a heat exchanger performance test system, including: a measurement and control work platform, a data acquisition unit, a compressor, a liquid nitrogen dewar and a vacuum cold box, wherein the vacuum cold box is provided with the liquid nitrogen dewar, and the liquid nitrogen dewar is immersed in a copper coil;

[0007] The helium is introduced into the vacuum cold box after being pressurized by the compressor. Inside the vacuum cold box, the hot end of the heat exchanger to be tested is connected to the air supply pipeline and the return air pipeline of the compressor, and the cold end is connected to the air inlet and the air outlet of the copper coil. Temperature sensors and pressure sensors are installed at the inlet and outlet positions of the heat exchanger to be tested. A plurality of temperature sensors are also distributed on the surface of the heat exchanger to be tested. The temperature sensor can continuously monitor the temperature change of the heat exchanger to be tested in real time, and the pressure sensor can dynamically monitor the pressure change at the inlet and outlet positions in real time. The measurement and control work platform can obtain the temperature data and pressure data of the heat exchanger to be tested through the data acquisition unit.

[0008] In some of the embodiments, a level gauge for testing the liquid level in the liquid nitrogen dewar is also included.

[0009] In some of the embodiments, the liquid nitrogen dewar is also connected with an exhaust valve and a liquid injection valve, so that the liquid nitrogen dewar can be replenished with liquid nitrogen in time according to the indication of the liquid level meter.

[0010] In some of the embodiments, a bypass valve is further provided at the outlet of the compressor.

[0011] In some of the embodiments, solenoid valves are provided on the pipelines between the cold end of the heat exchanger to be tested and the air inlet and the air outlet of the copper coil, and the solenoid valves work in an alternating on-off manner.

[0012] In some of the embodiments, the measurement and control work platform can control the working frequency of the solenoid valve through the data acquisition unit.

[0013] In some of the embodiments, a mass flow meter is provided on both the air supply pipeline and the air return pipeline of the compressor, and the mass flow meter is used for real-time monitoring of the helium flow rate.

[0014] In some of the embodiments, a stop valve is further provided between the compressor and the mass flow meter, and the stop valve is connected to a pressure stabilizing tank.

[0015] In some of the embodiments, the heat exchanger to be tested is a compact heat exchanger.

[0016] The utility model adopts the above technical solution, and its beneficial effects are as follows:

[0017] The utility model provides a heat exchanger performance test system, in which helium is introduced into the vacuum cold box after being pressurized by the compressor. Inside the vacuum cold box, the hot end of the heat exchanger to be tested is connected to the air supply pipeline and the air return pipeline of the compressor, and its cold end is connected to the air inlet and the air outlet of the copper coil. Temperature sensors and pressure sensors are installed at the inlet and outlet positions of the heat exchanger to be tested. A plurality of temperature sensors are also distributed on the surface of the heat exchanger to be tested. The temperature sensor can continuously monitor the temperature change of the heat exchanger to be tested in real time, and the pressure sensor can dynamically monitor the temperature change of the heat exchanger to be tested in real time. The pressure changes at the inlet and outlet positions are monitored regularly, and the measurement and control work platform can obtain the temperature data and pressure data of the heat exchanger to be tested through the data acquisition unit. The test system proposed by the utility model is used to test the heat exchange performance of the partition-wall heat exchanger in the pulse tube (or piston) expansion refrigerator. It can accurately evaluate the heat exchange efficiency of the heat exchanger and the cold or heat storage capacity of the wall under different mass flow rates and different switching frequencies, so as to have a deeper understanding of the heat exchange mechanism of the heat exchanger in the actual operating environment, thereby providing a scientific basis for optimizing the design and improving the performance of the heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments of the utility model or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic structural diagram of a heat exchanger performance testing system provided in one embodiment of the utility model. DETAILED DESCRIPTION

[0020] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0021] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0022] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0024] See also Figure 1 The embodiment of the utility model provides a heat exchanger performance test system, including: a measurement and control work platform 10, a data acquisition unit 20, a compressor 30, a liquid nitrogen dewar 40 and a vacuum cold box 50, wherein the vacuum cold box 50 is provided with the liquid nitrogen dewar 40, and the liquid nitrogen dewar 40 is immersed in a copper coil 70. The specific implementation of each structure is described in detail below.

[0025] In this embodiment, the test system uses helium as the working medium. The system obtains a certain flow of helium from the gas source, and the helium is introduced into the vacuum cold box 50 after being pressurized by the compressor 30. Inside the vacuum cold box 50, the hot end of the heat exchanger 60 to be tested is connected to the air supply pipeline and the return air pipeline of the compressor 30, and its cold end is connected to the air inlet and the air outlet of the copper coil 70 to ensure that the inlet temperature of the cold fluid flowing through the heat exchanger sample is the liquid nitrogen temperature. The inlet and outlet positions of the heat exchanger 60 to be tested are both installed with a temperature sensor 61 and a pressure sensor 62. The surface of the heat exchanger 60 to be tested is also distributed with a plurality of temperature sensors 61. The temperature sensor 61 can continuously monitor the temperature change of the heat exchanger to be tested in real time, and the pressure sensor 62 can dynamically monitor the pressure change at the inlet and outlet positions in real time. The measurement and control work platform 10 can obtain the temperature data and pressure data of the heat exchanger 60 to be tested through the data acquisition unit 20.

[0026] In this embodiment, the heat exchanger performance test system further includes a liquid level gauge 41 for testing the liquid level in the liquid nitrogen dewar 40. An exhaust valve 42 and a liquid injection valve 43 are also connected to the liquid nitrogen dewar 40. Under the action of the exhaust valve 42 and the liquid injection valve 43, liquid nitrogen can be replenished in the liquid nitrogen dewar 40 in time according to the indication of the liquid level gauge 41.

[0027] In the embodiment, a bypass valve 31 is further provided at the outlet of the compressor 30 .

[0028] It can be understood that the mass flow rate through the heat exchanger 60 to be tested can be accurately controlled by adjusting the opening of the bypass valve 31 at the outlet of the compressor 30 .

[0029] In this embodiment, solenoid valves 71 (72) are provided on the pipelines between the cold end of the heat exchanger 60 to be tested and the air inlet and outlet of the copper coil 70, and the solenoid valves work in an alternating on-off manner.

[0030] In this embodiment, the measurement and control work platform 10 can control the working frequency of the solenoid valve through the data acquisition unit 20 .

[0031] It can be understood that the solenoid valve is used to control the hot and cold fluids flowing through the heat exchanger 60 in the test system, so as to achieve precise adjustment of the fluid switching frequency, and realize automatic control of the system through the measurement and control working level 10, thereby ensuring the reliability and accuracy of the test results.

[0032] It should be noted that: since the system is designed with solenoid valves 71 and 72, they work in an alternating on-off manner, and the adjustment and control of their working frequency are completed through the program written on the measurement and control work platform 10, but this working mode will cause the flow of each pipeline in the system to continue to fluctuate.

[0033] Furthermore, a mass flow meter 80 is provided on both the air supply pipeline and the air return pipeline of the compressor 30 , and the mass flow meter 80 is used for real-time monitoring of the helium flow rate.

[0034] It can be understood that the test system provided in this embodiment is provided with mass flow meters 80 on both the air supply pipeline and the air return pipeline of the compressor 30 to achieve real-time monitoring of the flow rate and ensure that the air supply and return volumes remain consistent.

[0035] Furthermore, a stop valve 90 is provided between the compressor 30 and the mass flow meter 80 , and the stop valve 90 is connected to a pressure stabilizing tank 91 .

[0036] It can be understood that in this embodiment, a pressure-stabilizing tank 91 is connected to the air supply end of the compressor 30 to ensure the stability of the pressure at the inlet of the high-pressure flow channel of the heat exchanger 60; similarly, a pressure-stabilizing tank 91 is also provided at the return air end to maintain the stability of the pressure at the outlet of the low-pressure flow channel of the heat exchanger 60. Such a design ensures the accuracy and reliability of the test process.

[0037] It can be understood that by providing the pressure stabilizing tank 91, the pressure stability of the high-pressure flow channel inlet and the low-pressure flow channel outlet of the heat exchanger 60 is ensured, and constant operating conditions can be maintained even in the case of flow fluctuations, which is crucial for accurately testing the performance of the heat exchanger.

[0038] In some embodiments, the heat exchanger 60 to be tested is a compact heat exchanger.

[0039] It should be noted that the heat exchanger sample 60 involved in the utility model is a compact heat exchanger, which is characterized by using a large heat capacity metal wall to effectively store cold or heat. In order to accurately monitor the performance of the heat exchanger, a temperature sensor 61 and a pressure sensor 62 are installed at the inlet and outlet of the heat exchanger sample 60. These sensors can monitor the temperature and pressure changes of the inlet and outlet of the heat exchanger in real time and dynamically, providing key data for the operating status of the system.

[0040] In some of the embodiments, in order to comprehensively evaluate the performance of the heat exchanger sample at different working stages, a total of 8 temperature sensors are evenly distributed on the upper and lower surfaces of the heat exchanger 60 along the fluid flow direction. These sensors are located at different monitoring points, and can continuously monitor the temperature changes of the heat exchanger wall during the complete heat exchange cycle in real time. Through these data, the cold or heat storage capacity of the metal wall of the heat exchanger sample 13 can be accurately evaluated, thereby ensuring the optimization of its design and performance.

[0041] Furthermore, in the hot half cycle, the measurement and control work platform 10 controls the electromagnetic valve 71 to close and opens the electromagnetic valve 72 at the same time, and the compressor 30 drives the high-pressure helium to flow into the hot fluid channel of the heat exchanger 60 through the pressure regulating tank 91, and then the helium flows through the copper coil 70 immersed in liquid nitrogen to achieve cooling; in the cold half cycle, the measurement and control work platform 10 switches the electromagnetic valve state, opens the electromagnetic valve 71 and closes the electromagnetic valve 72, so that the low-temperature helium flows from the copper coil 70 into the cold fluid channel of the heat exchanger 60, and returns to the return air end of the compressor 30 through another pressure regulating tank 91. This process is repeated until the outlet temperature of the heat exchanger 60 reaches a stable state, at which time the temperature, pressure and flow data are collected.

[0042] It can be understood that by adjusting the opening of the bypass valve 31 and selecting the copper coil 70 with a suitable gas storage volume, the system can accurately control the flow rate of helium. At the same time, the measurement and control work platform 10 can also control the frequency of alternating opening and closing of the solenoid valve 71 and the solenoid valve 72, thereby achieving a comprehensive and accurate evaluation of the performance of the heat exchanger under different working fluid flow rates and different heat exchange cycle conditions.

[0043] The heat exchanger performance testing system provided by the above-mentioned embodiment of the utility model is used to test the heat exchange performance of the partition-wall heat exchanger in the pulse tube (or piston) expansion refrigerator, and can accurately evaluate the heat exchange efficiency of the heat exchanger and the cold or heat storage capacity of the wall of the heat exchanger under different mass flow rates and different switching frequencies, so as to have a deeper understanding of the heat exchange mechanism of the heat exchanger in the actual operating environment, thereby providing a scientific basis for optimizing the design and improving the performance of the heat exchanger.

[0044] It can be understood that the technical features of the above-described embodiments can be arbitrarily combined. In order to make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0045] The above are only preferred embodiments of the present invention, and only specifically describe the technical principles of the present invention. These descriptions are only for the purpose of explaining the principles of the present invention, and cannot be interpreted as limiting the scope of protection of the present invention in any way. Based on the explanation here, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention, and other specific implementation methods of the present invention that can be associated with by technicians in this field without creative labor, should be included in the scope of protection of the present invention.

Claims

1. A heat exchanger performance testing system, characterized in that: include: A measurement and control work platform, a data acquisition unit, a compressor, a liquid nitrogen dewar and a vacuum cold box, wherein the vacuum cold box is provided with the liquid nitrogen dewar, and the liquid nitrogen dewar is immersed in a copper coil; The helium is introduced into the vacuum cold box after being pressurized by the compressor. Inside the vacuum cold box, the hot end of the heat exchanger to be tested is connected to the air supply pipeline and the return air pipeline of the compressor, and the cold end is connected to the air inlet and the air outlet of the copper coil. Temperature sensors and pressure sensors are installed at the inlet and outlet positions of the heat exchanger to be tested. A plurality of temperature sensors are also distributed on the surface of the heat exchanger to be tested. The temperature sensor can continuously monitor the temperature change of the heat exchanger to be tested in real time, and the pressure sensor can dynamically monitor the pressure change at the inlet and outlet positions in real time. The measurement and control work platform can obtain the temperature data and pressure data of the heat exchanger to be tested through the data acquisition unit.

2. The heat exchanger performance testing system according to claim 1, characterized in that: Also included is a liquid level gauge for testing the liquid level in the liquid nitrogen dewar.

3. The heat exchanger performance testing system according to claim 2, characterized in that: The liquid nitrogen dewar is also connected with an exhaust valve and a liquid injection valve, so that liquid nitrogen can be replenished in the liquid nitrogen dewar in time according to the indication of the liquid level meter.

4. The heat exchanger performance testing system according to claim 1, characterized in that: A bypass valve is also provided at the outlet of the compressor.

5. The heat exchanger performance testing system according to claim 1, characterized in that: Solenoid valves are provided on the pipelines between the cold end of the heat exchanger to be tested and the air inlet and the air outlet of the copper coil, and the solenoid valves work in an alternating on-off manner.

6. The heat exchanger performance testing system according to claim 5, characterized in that: The measurement and control work platform can control the working frequency of the solenoid valve through the data acquisition unit.

7. The heat exchanger performance testing system according to claim 6, characterized in that: Mass flow meters are provided on both the air supply pipeline and the air return pipeline of the compressor, and the mass flow meters are used for real-time monitoring of the helium flow rate.

8. The heat exchanger performance testing system according to claim 7, characterized in that: A stop valve is also provided between the compressor and the mass flow meter, and the stop valve is connected to a pressure stabilizing tank.

9. The heat exchanger performance testing system according to claim 1, characterized in that: The heat exchanger to be tested is a compact heat exchanger.

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