Wide-working-condition and high-stability two-phase experiment circulating system and testing method thereof

Abstract

The invention discloses a wide-working-condition and high-stability two-phase experiment circulating system and a testing method thereof, and relates to the field of electronic device heat management, and the experiment circulating system comprises a pumping unit, a flow control and pressure stabilization unit, a pressure control unit, a temperature control unit, a condensation unit and a data acquisition unit. According to the experimental system, a wide-working-condition and high-stability two-phase flow cycle test environment is realized through cooperation of the pumping unit and the flow control and pressure stabilization unit, the flow heat exchange performance of the two-phase flow heat exchanger at different inlet flows, supercooling degrees and dryness can be actually tested, and multi-dimensional data such as temperature, pressure and flow state of each key node in a loop can be monitored in real time; the comprehensive performance of the heat exchanger is completely reflected, and experimental basis and design reference are provided for operation of a two-phase flow cooling system of an electronic device and optimization design of the heat exchanger.

Description

Technical Field

[0001] This invention belongs to the field of thermal management technology for electronic devices, and specifically relates to a two-phase experimental cycle system with wide operating conditions and high stability, and its testing method. Background Technology

[0002] Two-phase flow cooling technology, based on the high latent heat phase change heat transfer process of refrigerants, boasts advantages such as high heat transfer coefficient, good temperature uniformity, and low pump power requirements, making it a research hotspot in the thermal management of high heat flux density electronic devices. However, due to the complex phase characteristics of gas-liquid two-phase flow, the flow pattern evolution, flow characteristics, and heat transfer performance of the refrigerant within the heat exchanger exhibit significant nonlinear characteristics with changes in saturation pressure, mass flow rate, and load heat power. Once the critical heat flux density is reached, it can easily lead to safety hazards such as localized overheating failure of electronic devices. Therefore, clarifying the mapping relationship between different operating parameters and the flow and heat transfer characteristics of the heat exchanger through experiments is of great guiding significance for promoting the engineering application of this technology in the field of electronic thermal management.

[0003] The flow rate of existing two-phase flow cooling technology experimental devices is entirely determined by the circulating pump, resulting in a dual technical bottleneck in its flow control mechanism: First, due to the working principle of the positive displacement pump, periodic pressure / flow pulsations inevitably occur in the loop, making it impossible to capture the dynamic evolution characteristics between pressure and flow rate of the two-phase heat exchanger itself; Second, the inherent mechanical characteristics of the pump make it difficult to achieve precise control of a wide range of flow rates, especially under the low flow rate conditions required by microchannel heat exchangers, making it difficult to maintain a stable flow state. This limitation of the flow control system has seriously restricted the reliability of experimental data and the applicability of operating conditions. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention aims to provide a wide-condition, high-stability two-phase experimental circulation system and its testing method. The experimental device of the present invention can be used to conduct high-stability tests on the actual flow heat transfer performance of two-phase heat exchangers under a wide range of flow and pressure conditions, providing theoretical basis and experimental support for the design and performance optimization of heat exchangers used in two-phase flow cooling technology for electronic devices.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A wide-condition, high-stability two-phase experimental circulation system includes an experimental section installed in the refrigerant circulation loop, a test sample installed in the experimental section, and the system further includes a pumping unit, a pressure control unit, a temperature control unit, a condensation unit, and a data acquisition unit; the test sample is a two-phase flow heat exchanger. The pumping unit is used to maintain a closed-loop circulation of the refrigerant in the circuit; The pressure control unit includes a liquid storage tank. The bottom of the liquid storage tank is connected in parallel to the circuit after the experimental section through a shut-off valve. It is used to store excess refrigerant in the system and to regulate the refrigerant pressure in the circuit by adjusting the temperature of the refrigerant in the tank. The temperature control unit is used to control the subcooling and dryness of the inlet refrigerant in the experimental section; The condensation unit is used to condense the refrigerant exiting the experimental section; The data acquisition unit is used to monitor and obtain thermodynamic parameters such as temperature, pressure, and flow rate at key locations in the experimental system in real time.

[0006] In one embodiment, the experimental section, serving as the mounting location for the test sample, includes two flexible, adjustable corrugated metal hoses for installing the test sample. These hoses are adjustable to accommodate different sample sizes and feature self-sealing interfaces and auxiliary shut-off valves at the front and rear for easy assembly and disassembly. The test sample can be a two-phase flow heat exchanger commonly used for cooling electronic devices, such as a parallel microchannel heat exchanger, a manifold microchannel heat exchanger, or a jet heat exchanger. In one specific installation method, the inlet and outlet of the test sample are threaded to a corresponding corrugated metal hose, forming a detachable fluid passage. By adjusting the bending shape and extension length of the corrugated metal hoses, the experimental section can accommodate test samples of different sizes, allowing for flexible adjustment of the mounting position and passage length.

[0007] In one embodiment, the pumping unit consists of a servo motor, a gear pump, and a filter. The gear pump is installed in the circuit, and the output of the servo motor is connected to the gear pump to provide power for overcoming the flow resistance of the system circuit and maintaining the closed-loop circulation of the refrigerant. The filter is installed before the inlet of the gear pump to filter out solid impurities that may be carried by the refrigerant in the circuit and protect the gear pump.

[0008] In one embodiment, the pressure control unit further includes a vent valve and a second constant-temperature water tank; the vent valve is located at the top of the liquid storage tank and can be manually opened for emergency pressure relief and discharge of non-condensable gases that may be mixed into the circuit; the second constant-temperature water tank is connected to the spiral heat exchange tube inside the liquid storage tank, and heats or cools the two-phase refrigerant in the liquid storage tank by sending constant-temperature circulating water into the tank to exchange heat with the refrigerant in the tank, thereby increasing or decreasing the pressure of the two-phase refrigerant in the tank, and thus regulating the refrigerant pressure in the circuit.

[0009] In one embodiment, a level gauge is installed on the outside of the storage tank based on the principle of communicating vessels, and the level gauge is used to monitor the refrigerant level inside the tank in real time.

[0010] In one embodiment, the temperature control unit consists of a plate heat exchanger, a first constant temperature water tank, an electric heater, and a power regulator; The plate heat exchanger is connected to a circuit on one side and to a first constant temperature water tank on the other side. The refrigerant is heated or cooled by adjusting the temperature of the circulating water in the first constant temperature water tank, thereby controlling the subcooling of the inlet refrigerant in the experimental section. The electric heater is located between the plate heat exchanger and the inlet of the experimental section. It is a cylindrical heating tube array inserted into the refrigerant pipeline. It uses the Joule effect to convert electrical energy into heat energy to heat the refrigerant. Its specific voltage and current are precisely controlled by the power regulator to achieve constant power heating and thus control the dryness of the refrigerant at the inlet of the experimental section.

[0011] In one embodiment, the condensation unit consists of a condenser and a chiller unit; The condenser is a shell-and-tube heat exchanger, with a chiller unit connected to the tube side and a refrigerant circuit connected to the shell side. The low-temperature chilled water and the two-phase refrigerant at the outlet of the experimental section exchange heat through the heat exchange tube wall without contact, thereby achieving the condensation of the refrigerant.

[0012] In one embodiment, the data acquisition unit consists of a mass flow meter in the loop and temperature sensors, pressure sensors, and sight glasses at key locations, used to monitor the refrigerant flow and heat exchange status in the circulation system in real time, and to provide data support and control basis for the pumping, flow control and pressure stabilization, pressure control, temperature control, and condensation units.

[0013] In one embodiment, the wide-condition, high-stability two-phase experimental cycle system further includes: a current control and voltage regulation unit; The current control and voltage regulation unit consists of an electronic regulating valve, a pulsation damper, and a dynamic regulating valve. The electronic regulating valve is connected in parallel to the circuit and specifically connected before and after the pumping unit. It is used to bypass part of the refrigerant at the outlet of the pumping unit and return it to the front of the pumping unit, in order to control the actual flow rate of the refrigerant passing through the experimental section. The pulsation damper is located after the pumping unit and is used to eliminate refrigerant pressure and flow pulsation caused by pump operation, thereby stabilizing fluid pressure and flow. The dynamic regulating valve is located between the pulsation damper and the test section. It automatically adjusts the valve opening according to the pressure difference before and after the valve to further stabilize the flow rate and balance the impact of the additional compressible volume brought by the pulsation damper on the overall pressure drop-flow characteristic curve of the loop, thereby improving the stability of the two-phase flow circulation.

[0014] The "wide operating conditions" mentioned in this invention refer to a system with a wide range of upper and lower limits for test conditions, and a flow rate range of 0.01~0.30 kg·s. -1 The pressure range can reach 0.1~2.0 MPa; the high stability refers to the small fluctuation of key thermodynamic parameters during the system test process, and the variation range of parameters such as pressure and flow rate at key locations of the system under steady state is less than 10%.

[0015] This invention also provides a test method for the aforementioned wide-condition, high-stability two-phase experimental cycle system, comprising the following steps: Step 1: Install the test sample in the experimental section, evacuate the circuit and charge the refrigerant until the liquid level in the storage tank reaches 1 / 2; Step 2: Adjust the refrigerant temperature in the liquid receiver to the saturation temperature corresponding to the saturation pressure, and adjust the refrigerant pressure in the circulation loop to the expected saturation pressure through the refrigerant pressure transmission between the tank and the loop. Step 3: Adjust the temperature of the chilled water in the condenser to be lower than the refrigerant saturation temperature to ensure that the refrigerant before the pumping unit is a subcooled liquid. Start the pumping unit to pump, and control the opening to ensure that the inlet flow rate of the experimental section reaches the set value. Step 4: Control the subcooling and dryness of the inlet refrigerant in the experimental section through the temperature control unit; Step 5: Once the refrigerant parameters before the experimental section meet the test conditions and remain stable, activate the external loads such as simulated heat sources and simulated vibration sources mounted on the surface of the test sample within the experimental section. The data acquisition unit then collects real-time refrigerant flow and heat transfer parameters at several locations within the system. In this invention, the external loads are mounted on the surface of the test sample using screws, clamps, adhesives, etc., rather than being installed inside the test sample.

[0016] In one embodiment, the temperature control unit consists of a plate heat exchanger, a first constant temperature water tank, an electric heater, and a power regulator; one side of the plate heat exchanger is connected to the circuit, and the other side is connected to the first constant temperature water tank; the electric heater is located between the plate heat exchanger and the inlet of the experimental section, and is an array of cylindrical heating tubes inserted into the refrigerant pipeline; In step 4, for subcooled conditions, the water temperature of the first constant temperature water tank is adjusted and the electric heater is not turned on, so that the refrigerant before the experimental section reaches the set subcooling degree; for superheated conditions, the water temperature of the first water tank is adjusted so that the refrigerant before the electric heater reaches the saturation state; the electric heating power required to achieve the set dryness degree is estimated by heat conservation, and the electric heater is made to heat at a constant power according to the required power by the power regulator, so that the refrigerant before the experimental section reaches the set dryness degree.

[0017] Compared with the prior art, the beneficial effects of the present invention are: (1) By coordinating the pumping unit and the flow control and pressure stabilization unit, the speed of the gear pump and the opening of the bypass electronic regulating valve are coupled to achieve the flow regulation efficiency, thus realizing a wider range of flow and pressure conditions. Furthermore, by adjusting the opening of the dynamic regulating valve through the contraction / expansion of the pulsation damper airbag and the differential pressure, the flow / pressure pulsation caused by the working principle of the circulating pump is eliminated, thus achieving high stability experimental testing.

[0018] (2) The experimental circulation system has precise pressure, flow and temperature control and high-frequency acquisition capabilities, which can realize real-time monitoring and dynamic control of multiple parameters, ensuring the accuracy and reproducibility of test results.

[0019] (3) The experimental cycle system is highly integrated, with the pipeline packaged in the form of a bench. The experimental section, main operating valves, switches and host computer control interface are all located on the bench surface, making it convenient to operate and conducive to conducting visual experiments. It has good scalability and economy. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the circulation system and components according to an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of the integrated bench geometry according to an embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of the installation structure of the test sample in the experimental section of this invention. Detailed Implementation

[0023] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings and examples.

[0024] This invention provides a wide-condition, high-stability two-phase experimental cycle system, such as... Figure 1 and Figure 2 As shown, it mainly consists of a pumping unit, a pressure control unit, a temperature control unit, a condensation unit, and a data acquisition unit, and may further preferably include a flow control and pressure stabilization unit.

[0025] The pumping unit mainly consists of a servo motor 1, a gear pump 2, and a filter 21. It is used to overcome the flow resistance of the system loop and maintain the closed-loop circulation of the refrigerant. The gear pump 2 is directly installed on the loop, and the output of the servo motor 1 is connected to it to provide power and facilitate speed control. The filter 21 is installed before the gear pump inlet to filter out solid impurities that may be present in the refrigerant in the loop, protecting the gear pump 2. In a preferred embodiment of the invention, the refrigerant is R134a, the servo motor 1 has a speed of 0~1800 RPM, the gear pump 2 has a flow rate of 0.03-0.25 kg / s, and the filter accuracy is 250 μm.

[0026] The pressure control unit mainly consists of a shut-off valve 12, a liquid storage tank 15, a level gauge 16, a vent valve 17, and a second constant-temperature water tank 18. The bottom of the liquid storage tank 15 is connected in parallel to the circulation loop after the experimental section 14 via the shut-off valve 12 to store excess refrigerant in the system. The level gauge 16, based on the principle of communicating vessels, is installed on the outside of the liquid storage tank 15 to monitor the refrigerant level in real time. The vent valve 17 is located at the top of the liquid storage tank 15 and can be manually opened for emergency pressure relief and to release any non-condensable gases that may have entered the circulation loop. The second constant-temperature water tank 18 provides constant-temperature water for heat exchange with the refrigerant in the liquid storage tank 15. Specifically, it is connected to a spiral heat exchange tube inside the liquid storage tank 15, sending constant-temperature circulating water into the tank to exchange heat with the refrigerant, heating / cooling the two-phase refrigerant in the liquid storage tank 15 to increase / decrease the pressure of the two-phase refrigerant in the tank, thereby regulating the refrigerant pressure in the overall circulation loop. In a preferred embodiment of the present invention, the shut-off valve 12 is a 5-point manual shut-off valve, the liquid storage tank 15 is a stainless steel 0.5 L volume, 2.5 MPa pressure-resistant tank, the liquid level gauge 16 is a magnetic float type liquid level gauge, and the circulating water temperature range of the second constant temperature water tank 18 is 15~80℃.

[0027] The temperature control unit mainly consists of a plate heat exchanger 7, a first constant-temperature water tank 8, an electric heater 9, and a power regulator 10. One side of the plate heat exchanger 7 is connected to the refrigerant circuit, and the other side is connected to the first constant-temperature water tank 8. By adjusting the temperature of the circulating water in the first constant-temperature water tank 8, the refrigerant is heated / cooled, thereby controlling the subcooling of the inlet refrigerant in experimental section 14. The electric heater 9 is a cylindrical heating tube array inserted into the refrigerant pipeline, utilizing the Joule effect to convert electrical energy into heat energy to heat the refrigerant. Its specific voltage and current can be precisely controlled by the power regulator 10 to achieve constant-power heating and thus control the dryness of the inlet refrigerant in experimental section 14. As a preferred embodiment of the present invention, the plate heat exchanger 7 has a stainless steel herringbone corrugated plate structure, and the circulating water temperature range of the first constant-temperature water tank 8 is 25~75℃.

[0028] The condensing unit mainly consists of a condenser 19 and a chiller unit 20. The condenser 19 is a shell-and-tube heat exchanger, with the chiller unit 20 connected to the tube side and the refrigerant circuit connected to the shell side. Low-temperature chilled water and the two-phase refrigerant at the outlet of the experimental section 14 exchange heat without contact through the heat exchange tube walls, achieving refrigerant condensation. In a preferred embodiment of the invention, the chiller unit 20 has a cooling capacity of 10 kW.

[0029] The data acquisition unit mainly consists of a mass flow meter 5 in the circulation loop and temperature sensors 22, pressure sensors 23, and a sight glass 11 at key locations. It is used to monitor the refrigerant flow and heat exchange status in the circulation system in real time and to provide data support and control basis for the pumping, flow control and pressure stabilization, pressure control, temperature control, and condensation units. In a preferred embodiment of the invention, the mass flow meter 5 is a Coriolis flow meter, the temperature sensor 22 is a PT100 resistance temperature detector (RTD), the pressure sensor 23 is a piezoresistive pressure sensor, and the sight glass 11 is a metal-glass composite sight glass.

[0030] The flow control and voltage regulation unit (if any) mainly consists of an electronic regulating valve 3, a pulsation damper 4, and a dynamic regulating valve 6. The electronic regulating valve 3 is connected in parallel before and after the gear pump 2. When the method of reducing the speed of the servo motor 1 to reduce the outlet flow of the gear pump 2 cannot achieve a stable expected low flow condition, the electronic regulating valve 3 is opened to bypass part of the refrigerant at the outlet of the gear pump 2 back to the front of the pump, which works in conjunction with the pumping unit to control the actual refrigerant flow through the experimental section 14. The pulsation damper 4 is located after the gear pump 2 and is used to eliminate refrigerant pressure and flow pulsations caused by the working principle of the gear pump, thereby stabilizing fluid pressure and flow. In a preferred embodiment of the present invention, the pulsation damper 4 is a stainless steel pneumatic type with a maximum pressure of 2.5 MPa.

[0031] The dynamic regulating valve 6 is located between the pulsation damper 4 and the experimental section 14. When the pressure difference between the valve and the upstream and downstream increases, the pressure-sensing diaphragm drives the valve core to move down and close the valve opening, increasing the local resistance and restoring the pressure difference to the set value. When the pressure difference between the valve and the upstream and downstream decreases, the pressure-sensing diaphragm drives the valve core to move up and open the valve opening, reducing the local resistance and restoring the pressure difference to the set value. This allows the valve opening to be automatically adjusted according to the pressure difference before and after the valve, further stabilizing the flow rate and balancing the impact of the additional compressible volume brought by the pulsation damper 4 on the overall pressure drop-flow characteristic curve of the circulation loop, thereby improving the stability of the two-phase flow circulation.

[0032] In practical applications, the conduit of this invention can be encapsulated as follows: Figure 2 The test bench shown has its main components, such as the servo motor 1, gear pump 2, and liquid storage tank 15, all placed inside the bench, which is neat and aesthetically pleasing. Only the test section 14, self-sealing interface 13, and auxiliary shut-off valve 24, which require frequent disassembly and operation, are retained on the bench surface, which is convenient for actual testing.

[0033] The structure of experimental segment 14 of the present invention is as follows Figure 3As shown, experimental section 14 includes two corrugated metal hoses. The test sample is a two-phase flow heat exchanger located between the two corrugated metal hoses. The outlet and inlet are each connected to the circulation system via a corrugated metal hose, forming a detachable fluid passage. By using corrugated metal hoses, their bending shape and extension length can be easily adjusted, thereby adjusting the position of the two-phase flow heat exchanger in the circulation system.

[0034] The specific testing steps provided in this embodiment of the invention mainly include: Step 1: Test sample installation and sealing test.

[0035] The test sample is purged with high-pressure air to remove metal debris and other impurities. The test sample is then installed in test section 14, ensuring proper pipe connections. High-pressure air is introduced to raise the pipe pressure to 2.0 MPa, and the system is allowed to stand. Pressure changes are monitored. If the pressure at each node remains unchanged within a specified time, the system is considered to have good sealing, and the next step can proceed. Otherwise, the entire circuit must be leak-tested, leaks repaired, and the sealing test repeated. This step ensures correct pipe connections and no leaks.

[0036] Step 2: Refrigerant charging.

[0037] Evacuate the entire system loop (if there is a vent valve 17, it must be closed) to achieve a vacuum level of 5×10⁻⁶. -2 Pa; The refrigerant charging machine is used to start charging the refrigerant into the circulation system. At the same time, the second constant temperature water tank 18, the chiller unit 20 condensate storage tank 15, and the gaseous refrigerant in the circuit can be started. The charging can be stopped when the refrigerant level in the storage tank 15 reaches 1 / 2 of the tank by observing the reading of the liquid level gauge 16. Step 3: Adjust the refrigerant saturation pressure.

[0038] The two-phase refrigerant in the liquid storage tank 15 can be heated / cooled by setting the circulating water temperature of the second constant temperature water tank 18 to the saturation temperature corresponding to the expected refrigerant saturation pressure. The refrigerant pressure in the circulation loop can be adjusted to the expected saturation pressure by transmitting the refrigerant pressure in the tank and pipeline.

[0039] Step 4: Flow settings.

[0040] The refrigerant before the pumping unit is a subcooled liquid, which can be ensured by adjusting the water supply temperature of the chiller unit 20 to be lower than the refrigerant saturation temperature. Pumping can then be started, specifically by starting the servo motor 1 to drive the gear pump 2 to begin circulation. The speed of the servo motor 1 and the opening of the electronic regulating valve 3 can be adjusted in tandem to ensure that the inlet flow rate of the experimental section 14 measured by the mass flow meter 5 reaches the set value.

[0041] Step 5: Set the subcooling / dryness.

[0042] For subcooling conditions, adjust the water temperature of the first constant temperature water tank 8 and do not turn on the electric heater 9 so that the refrigerant in front of the experimental section 14 reaches the set subcooling degree. For overheating conditions, the water temperature of the first water tank 8 is adjusted to make the refrigerant in front of the electric heater 9 reach saturation; the electric heating power required to achieve the set dryness is estimated by heat conservation, and the electric heater 9 is made to heat at a constant power according to the required power through the power regulator 10, so that the refrigerant in front of the experimental section 14 reaches the set dryness.

[0043] Step 6: Experimental testing and data collection.

[0044] Once the key parameters such as refrigerant saturation pressure, temperature, and flow rate in front of test section 14 meet the test conditions and remain stable, simulate external loads such as heat sources and vibration sources in the test section are started. The refrigerant flow and heat transfer status parameters at each key location in the system are collected in real time through devices such as mass flow meter 5, temperature sensor 22, and pressure sensor 23 to comprehensively evaluate the overall performance of the heat exchanger.

[0045] Step 7: Test sample removal / replacement.

[0046] After the experiment is completed, close the auxiliary shut-off valves 24 before and after the experimental section 14, and use the self-sealing interface 13 to quickly and conveniently remove the test sample from the experimental section 14. When replacing the test sample, it is not necessary to repeat the overall system sealing test and refrigerant charging process shown in steps 1 and 2 above. It is only necessary to close the auxiliary shut-off valves 24 before and after the test section 14, and perform sealing tests and vacuuming on the replaced test sample and the part of the pipeline between the sample and the auxiliary shut-off valve 24.

[0047] In summary, the system of this invention, through the coordinated pumping unit and the flow control and pressure stabilization unit, achieves a wide-condition, highly stable two-phase circulation test environment. It can actually test the flow heat transfer performance of two-phase flow heat exchangers under different inlet flow rates, subcooling, and dryness, and monitor multi-dimensional data such as temperature, pressure, and flow state of each key node in the loop in real time, so as to fully reflect the comprehensive performance of the heat exchanger and provide experimental basis and design reference for the operation of two-phase flow cooling systems for electronic devices and the optimized design of heat exchangers.

[0048] Specific examples have been used in this invention to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this application; at the same time, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be construed as a limitation of this application.

Claims

1. A two-phase experimental circulation system with wide operating conditions and high stability, comprising an experimental section (14) installed in a refrigerant circulation loop, wherein a test sample is installed in the experimental section (14), characterized in that, The system also includes a pumping unit, a pressure control unit, a temperature control unit, a condensation unit, and a data acquisition unit; the test sample is a two-phase flow heat exchanger. The pumping unit is used to maintain the closed-loop circulation of refrigerant within the circuit; The pressure control unit includes a liquid storage tank (15), the bottom of which is connected in parallel to the circuit after the experimental section (14) via a shut-off valve (12) to store excess refrigerant in the system and to regulate the refrigerant pressure in the circuit by adjusting the temperature of the refrigerant in the tank. The temperature control unit is used to control the subcooling and dryness of the inlet refrigerant in the experimental section (14); The condensation unit is used to condense the two-phase refrigerant at the outlet of the experimental section (14); The data acquisition unit is used to monitor and obtain thermodynamic parameters at key locations in the experimental system in real time.

2. The wide-condition, high-stability two-phase experimental cycle system according to claim 1, characterized in that, The experimental section (14) includes two flexible and adjustable corrugated metal hoses for installing test specimens. The inlet and outlet of the test specimens are respectively connected to a corrugated metal hose on the corresponding side by threads to form a detachable fluid passage. By adjusting the bending shape and extension length of the corrugated metal hoses, the experimental section (14) can be adapted to test specimens of different sizes and specifications, and the installation position and passage length can be flexibly adjusted. The experimental section (14) has self-sealing interfaces (13) and auxiliary shut-off valves (24) at both the front and rear to facilitate disassembly and assembly. The two-phase flow heat exchanger is a parallel microchannel heat exchanger, a manifold microchannel heat exchanger, or a jet heat exchanger.

3. The wide-condition, high-stability two-phase experimental cycle system according to claim 1, characterized in that, The pumping unit consists of a servo motor (1), a gear pump (2) and a filter (21). The servo motor (1) drives the gear pump (2) to drive the refrigerant to overcome the flow resistance of the system circuit and maintain circulation. The filter (21) is located before the inlet of the gear pump (2) and is used to filter out solid impurities that may be carried by the refrigerant in the circuit and protect the gear pump (2). The pressure control unit also includes a vent valve (17) and a second constant temperature water tank (18); the vent valve (17) is located at the top of the liquid storage tank (15) and is used to release pressure and discharge non-condensable gases mixed in the circuit; the second constant temperature water tank (18) is connected to the spiral heat exchange tube inside the liquid storage tank (15), and heats or cools the two-phase refrigerant in the liquid storage tank (15) by sending constant temperature circulating water into the tank to exchange heat with the refrigerant in the tank, thereby increasing or decreasing the pressure of the two-phase refrigerant in the tank, and thus regulating the refrigerant pressure in the circuit.

4. The wide-condition, high-stability two-phase experimental cycle system according to claim 1, characterized in that, The temperature control unit consists of a plate heat exchanger (7), a first constant temperature water tank (8), an electric heater (9), and a power regulator (10); The plate heat exchanger (7) is connected to the circuit on one side and to the first constant temperature water tank (8) on the other side. The temperature of the circulating water in the first constant temperature water tank (8) is adjusted to heat or cool the refrigerant, thereby controlling the subcooling of the inlet refrigerant in the experimental section (14). The electric heater (9) is located between the plate heat exchanger (7) and the inlet of the experimental section (14). It is a cylindrical heating tube array inserted into the refrigerant pipeline. It uses the Joule effect to convert electrical energy into heat energy to heat the refrigerant. Its specific voltage and current are precisely controlled by the power regulator (10) to achieve constant power heating and thus control the dryness of the refrigerant at the inlet of the experimental section (14).

5. The wide-condition, high-stability two-phase experimental cycle system according to claim 1, characterized in that, The condensation unit consists of a condenser (19) and a chiller unit (20); The condenser (19) is a shell-and-tube heat exchanger. The tube side is connected to the chiller unit (20), and the shell side is connected to the refrigerant circuit. The low-temperature chilled water and the two-phase refrigerant at the outlet of the experimental section (14) exchange heat without contact through the heat exchange tube wall to achieve the condensation of the refrigerant.

6. The wide-condition, high-stability two-phase experimental cycle system according to claim 1, characterized in that, The data acquisition unit consists of a mass flow meter (5) in the loop and temperature sensors (22), pressure sensors (23), and sight glasses (11) at key locations. It is used to monitor the refrigerant flow and heat exchange status in the circulation system in real time and to provide data support and control basis for the pumping, flow control and pressure stabilization, pressure control, temperature control and condensation units.

7. The wide-condition, high-stability two-phase experimental cycle system according to claim 1, characterized in that, The term "wide operating conditions" refers to the system's test operating conditions with a flow rate range of 0.01~0.30 kg·s. -1 The pressure range is 0.1~2.0 MPa; the high stability refers to the variation range of thermodynamic parameters during the system test process being less than 10%.

8. The wide-condition, high-stability two-phase experimental cycle system according to any one of claims 1 to 7, characterized in that, The system also includes: a current control and voltage regulation unit; The current control and voltage regulation unit consists of an electronic regulating valve (3), a pulsation damper (4), and a dynamic regulating valve (6); The electronic regulating valve (3) is connected in front of and behind the pumping unit to bypass part of the refrigerant at the outlet of the pumping unit and return it to the front of the pumping unit, in order to control the actual flow rate of the refrigerant flowing through the experimental section (14). The pulsation damper (4) is located after the pumping unit and is used to eliminate the refrigerant pressure and flow pulsation caused by the pump operation, thereby stabilizing the fluid pressure and flow. The dynamic regulating valve (6) is located between the pulsation damper (4) and the experimental section (14). It automatically adjusts the valve opening according to the pressure difference before and after the valve to stabilize the flow rate and balance the influence of the additional compressible volume brought by the pulsation damper (4) on the overall pressure drop-flow characteristic curve of the loop, thereby improving the stability of the two-phase flow circulation.

9. The test method for the wide-condition, high-stability two-phase experimental cyclic system as described in claim 1, characterized in that, Includes the following steps: Step 1: Install the test sample in the experimental section (14), evacuate the circuit and charge the refrigerant until the liquid level in the storage tank (15) reaches 1 / 2; Step 2: Adjust the temperature of the refrigerant in the liquid storage tank (15) to the saturation temperature corresponding to the saturation pressure, and adjust the refrigerant pressure in the circulation loop to the expected saturation pressure through the refrigerant pressure transmission between the tank and the loop. Step 3: Adjust the temperature of the chilled water in the condenser (19) to be lower than the refrigerant saturation temperature to ensure that the refrigerant before the pumping unit is a subcooled liquid. Start the pumping unit to pump and control the opening to make the inlet flow rate of the experimental section (14) reach the set value. Step 4: Control the subcooling and dryness of the inlet refrigerant in the experimental section (14) through the temperature control unit; Step 5: Once the refrigerant parameters in the experimental section (14) meet the test conditions and remain stable, start the external load of the simulated heat source and simulated vibration source installed on the surface of the test sample in the experimental section (14), and collect the refrigerant flow heat transfer state parameters at several locations in the system in real time through the data acquisition unit.

10. The test method according to claim 9, characterized in that, The temperature control unit consists of a plate heat exchanger (7), a first constant temperature water tank (8), an electric heater (9), and a power regulator (10); the plate heat exchanger (7) is connected to the circuit on one side and to the first constant temperature water tank (8) on the other side; the electric heater (9) is located between the plate heat exchanger (7) and the inlet of the experimental section (14), and is a cylindrical heating tube array inserted into the refrigerant pipeline; In step 4, for the subcooled condition, the water temperature of the first constant temperature water tank (8) is adjusted and the electric heater (9) is not turned on, so that the refrigerant in front of the experimental section (14) reaches the set subcooled degree; for the overheated condition, the water temperature of the first water tank (8) is adjusted so that the refrigerant in front of the electric heater (9) reaches the saturated state; the electric heating power required to achieve the set dryness is estimated by heat conservation, and the electric heater (9) is heated at the required power by the power regulator (10) so that the refrigerant in front of the experimental section (14) reaches the set dryness.

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