Negative pressure controlled phase change heat exchange system

Abstract

The invention belongs to the technical field of airborne environmental control / heat management, and particularly relates to a negative-pressure-controlled phase-change heat exchange system which comprises a phase-change evaporation device for storing a phase-change working medium, and the phase-change working medium cools a working medium in a heat exchange unit through phase-change heat absorption; the heat exchange unit and the heat dissipation equipment form a circulation loop, and the circulation loop transfers heat through a working medium; the anti-freezing heating unit is used for heating the phase change working medium in the phase change evaporation device and preventing the working medium from being frozen under the condition of too low temperature; the vacuum generator is used for applying negative pressure into the phase change evaporation device and reducing the saturation temperature of the phase change working medium; the control unit detects the temperature, the pressure and the liquid level in the phase change evaporation device through a sensor, adjusts the vacuum degree in the phase change evaporation device according to control requirements, and starts the anti-freezing heating unit before the freezing temperature is reached, and the system has the advantages of being large in adaptive heat capacity, capable of achieving heat dissipation heat sink self-realization, low in airborne energy consumption, high in expansibility and the like.

Description

Technical Field

[0001] This application belongs to the field of airborne environmental control / thermal management technology, and specifically relates to a negative pressure controlled phase change heat transfer system. Background Technology

[0002] In the field of equipment, the power consumption and heat dissipation capacity of equipment are increasing exponentially. The contradiction between high-power, high-heat-flux-density heat dissipation and insufficient resources is becoming increasingly prominent, which has become a bottleneck restricting equipment development. In particular, the beyond-visual-range detection and attack range required for aviation equipment has increased significantly, resulting in a serious mismatch between the high-power heat dissipation of mission system equipment and airborne heat sinks. Summary of the Invention

[0003] To address the aforementioned problems, this application provides a negative pressure controlled phase change heat transfer system, comprising:

[0004] A phase change evaporation device stores a phase change working medium, which absorbs heat during phase change to cool the working fluid in the heat exchange unit.

[0005] The heat exchange unit forms a circulation loop with the heat dissipation equipment, and the circulation loop transfers heat through the working fluid.

[0006] The antifreeze heating unit heats the phase change working fluid in the phase change evaporator to prevent the working fluid from freezing under excessively low temperature conditions.

[0007] A vacuum generator applies negative pressure to the phase change evaporation device to lower the saturation temperature of the phase change working fluid.

[0008] The control unit detects the temperature, pressure, and liquid level inside the phase change evaporator through sensors, adjusts the vacuum level inside the phase change evaporator according to control requirements, and starts the antifreeze heating unit before the freezing temperature is reached.

[0009] Preferably, the phase change evaporation apparatus is equipped with:

[0010] Emergency pressure relief vents are used for overpressure relief;

[0011] The exhaust port is connected to the working fluid inlet of the vacuum generator.

[0012] The drain port is connected to the discharge device to remove residual phase change working fluid from the phase change evaporator.

[0013] The filling port is used to replenish the phase change working medium.

[0014] Preferably, it also includes an emergency pressure relief unit, the pressure relief inlet of the emergency pressure relief unit is connected to the emergency pressure relief outlet, and the emergency pressure relief valve is a mechanical safety mechanism. When the pressure inside the phase change evaporator exceeds the threshold, the pressure relief channel is automatically opened, and the gas flows from the emergency pressure relief outlet through the pressure relief inlet to the pressure relief outlet and is discharged into the environment.

[0015] Preferably, the start and stop of the antifreeze heating unit is controlled by the control unit according to the temperature sensor signal: heating is started when the temperature is lower than the freezing point of the working fluid; heating is stopped when the temperature is 2°C higher than the freezing point.

[0016] Preferably, the control unit executes liquid level protection logic: when the liquid level gauge placed in the phase change evaporator detects that the liquid level is lower than the lower limit threshold, it sends an alarm signal to the host computer and cuts off the power supply to the heat dissipation device.

[0017] Preferably, the vacuum generator is connected to the gas source regulating valve. When the pressure sensor test data inside the phase change evaporator is higher than the set value, the control unit opens the gas source regulating valve, and the vacuum generator generates negative pressure through the high-pressure gas ejection of the gas source regulating valve to draw in the gas from the phase change evaporator.

[0018] Compared with traditional equipment cooling systems, the negative pressure phase change heat exchange system provided in this application has the advantages of large heat capacity, self-realization of heat sink, low onboard energy consumption, and strong scalability. Attached Figure Description

[0019] Figure 1 This is the overall architecture diagram of the negative pressure controlled phase change heat exchange system of this application;

[0020] Figure 2 This is a schematic diagram of the working part of the negative pressure control phase change heat exchange system under low environmental pressure state in this application;

[0021] Figure 3 This is a schematic diagram of the high-pressure operating section of the negative pressure control phase change heat exchange system of this application.

[0022] Figure 4 This is a schematic diagram of the emergency safety pressure relief working part of the negative pressure control phase change heat exchange system of this application;

[0023] Figure 5 This is a partial architecture diagram of the anti-icing state of the negative pressure controlled phase change heat exchange system of this application;

[0024] Figure 6 This is a partial architecture diagram of the emission state of the negative pressure controlled phase change heat exchange system of this application;

[0025] Figure 7 This is a partial architecture diagram of the liquid level alarm status of the phase change heat exchange system under negative pressure control in this application;

[0026] Figure 8 This is a schematic diagram of the filling state portion of the negative pressure controlled phase change heat exchange system of this application. Detailed Implementation

[0027] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this application, and are only used to explain this application, not to limit this application. It should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings. Other related parts can be referred to the general design. In the absence of conflict, the embodiments and technical features in the embodiments of this application can be combined with each other to obtain new embodiments.

[0028] like Figure 1 As shown, the phase change evaporation device 1 is used to store the phase change working medium and exchange heat with the heat exchange unit 2. It cools the working medium in the heat exchange unit by absorbing heat through phase change. It has three ports: emergency pressure relief port 1-1 is used to relieve pressure when there is internal overpressure in the fault state; exhaust port 1-2 is used to discharge the vapor after phase change in the normal working state; and liquid discharge port 1-3 is used to discharge the internal residual water in the non-working state.

[0029] Heat exchange unit 2 is used to transfer the heat generated by the heat dissipation equipment and exchange heat with the phase change working fluid in the phase change evaporator 1. It has two outlets: the hot fluid inlet 2-1 is connected to the heat dissipation equipment outlet A pipe, and the hot fluid outlet is connected to the heat dissipation equipment inlet B through a pipe.

[0030] The antifreeze heating unit 3 is used to heat the phase change working fluid in the phase change evaporation device 1 to prevent the working fluid from freezing under excessively low temperature conditions.

[0031] Emergency pressure relief unit 4 is used for overpressure protection of phase change evaporator 1. When overpressure occurs, it opens the exhaust pressure relief, including pressure relief inlet 4-1 and pressure relief outlet 4-2.

[0032] The vacuum generator 5 is used to generate negative pressure inside the phase change evaporation device 1 to reduce the saturation temperature of the phase change working fluid. It includes an exhaust port 5-1, a gas source inlet 5-2, and an outlet 5-3.

[0033] The gas source regulating valve 6 is used to regulate the pressure and flow rate of the gas source inlet of the vacuum generator 5, including the gas source regulating valve inlet 6-2 and the gas source regulating valve outlet 6-1;

[0034] The discharge device 7 is used to remove the residual phase change working fluid in the phase change evaporation device 1, and includes the discharge device inlet 7-1 and the discharge device inlet 7-1;

[0035] The control unit 8 is used for system control and status monitoring. The monitoring status includes the temperature, pressure and liquid level in the phase change evaporator 1. It also adjusts the vacuum degree in the phase change evaporator 1 according to control requirements and starts the antifreeze heating unit 3 before the freezing temperature is reached.

[0036] Pressure sensor 9 is used to test the pressure inside the phase change evaporator 1, provide status information to control unit 8, and start adjusting the gas source regulating valve 6 according to the status to generate the required vacuum conditions inside the phase change evaporator 1.

[0037] Temperature sensor 10 is used to test the temperature inside phase change evaporation device 1 and to provide an on / off signal for the antifreeze heating unit to stop operating.

[0038] The liquid level sensor 11 is used to test the working fluid capacity in the phase change evaporation device 1, and the control unit 8 transmits an alarm signal to the host computer when it receives a low liquid level.

[0039] like Figure 1 When at high altitude, the ambient pressure is low and the saturation temperature meets the highest temperature condition at port B, the heat transferred from port A exchanges with the phase change working fluid through heat exchange unit 2. The phase change working fluid absorbs heat and evaporates, and is discharged into vacuum generator 5 through phase change evaporation device 1. Without increasing the vacuum degree, it is discharged into the atmospheric environment through vacuum generator 5.

[0040] When the ambient pressure is too high or does not meet the saturation temperature control requirements in low or medium altitude conditions, the heat introduced from port A exchanges heat with the phase change working fluid through heat exchange unit 2. The phase change working fluid absorbs heat and evaporates, and is discharged into the vacuum generator 5 through the phase change evaporation device 1. The control unit 8 controls the on / off mechanism on the power gas source passage of the vacuum generator to connect and disconnect according to the information from the absolute pressure sensor, thereby increasing the vacuum degree in the phase change evaporation device and discharging the vapor into the atmospheric environment through the vacuum generator 5.

[0041] When the exhaust pipe is blocked or the system malfunctions, causing the internal pressure of the phase change evaporator 1 to exceed the ambient pressure, the mechanical emergency pressure relief unit 4 opens to release the pressure and prevent the system from being damaged by overpressure.

[0042] When the internal temperature of the phase change evaporator 1 is lower than the freezing point, in order to prevent the phase change working medium from freezing and causing system failure or damage, the control unit 8 controls the antifreeze heating unit to work after receiving the low temperature signal from the temperature sensor 10, so as to heat the phase change working medium.

[0043] The liquid level inside the phase change evaporator 1 is transmitted to the controller 8 via a liquid level sensor. The controller receives the liquid level signal and controls the process when the liquid level falls below the lower limit.

[0044] When the system is parked on the ground and not in operation, the discharge unit 7 passage can be opened to discharge the remaining working fluid in the phase change evaporator.

[0045] Depending on the usage scenario, the working modes are as follows:

[0046] like Figure 2Operating under low environmental pressure: The working fluid from outlet A of the high-power equipment flows into inlet 2-1 of the heat exchange unit. After heat exchange in heat exchange unit 2 and phase change evaporator 1, it flows into inlet B of the task equipment through outlet 2-2 of the heat exchange unit. After absorbing heat, the phase change working fluid reaches the evaporation temperature and generates steam. It enters the vacuum generator steam inlet 5-1 through the normal exhaust passage 1-2 of phase change evaporator 1. At this time, the vacuum degree in phase change evaporator 1 is high, and the high-pressure gas port 5-2 of the vacuum generator is not connected to the air intake. The steam flows directly into the ambient atmosphere from outlet 5-3 of the vacuum generator.

[0047] like Figure 3 Operating under high environmental pressure: When the absolute pressure sensor 9 receives test data exceeding the set value, the control unit 8 controls the gas source regulating valve 6 to open, allowing high-pressure gas to flow into the gas source regulating valve inlet 6-2 and out through the gas source regulating valve outlet 6-1 into the vacuum generator supply interface 5-2. The vacuum generator 6 then operates, reducing the pressure inside the phase change evaporator 1. The working fluid from the high-power equipment outlet A flows into the heat exchange unit inlet 2-1, and after heat exchange between the working fluid in the conversion unit 2 and the phase change evaporator 1, it flows into the task equipment inlet B through the heat exchange unit outlet 2-2. After absorbing heat, the phase change working fluid reaches the evaporation temperature and generates vapor, which enters the vacuum generator vapor inlet 5-1 through the normal exhaust passage 1-2 of the phase change evaporator 1. Inside the vacuum generator, the vapor mixes with the gas at the vacuum generator gas source inlet 5-2 and flows into the ambient atmosphere through the vacuum generator outlet 5-3.

[0048] like Figure 4 Emergency safety pressure relief operation: When the discharge passage is blocked or the vacuum generator 5 fails to discharge, the heat of the heat exchange device 2 is transferred to the phase change working fluid to produce evaporation. After a certain period of time, the pressure inside the phase change evaporation device 1 rises and exceeds the limit pressure of the mechanical emergency pressure relief unit 4. The steam enters the pressure relief unit inlet 4-1 from the safety exhaust port 1-1 inside the phase change evaporation device 1 and is discharged into the environment through the pressure relief unit outlet 4-2.

[0049] like Figure 5 Anti-icing state: When the internal temperature of the phase change evaporator 1 is lower than the freezing point, the controller 8 receives a low temperature signal from the temperature sensor 10 and starts the anti-freeze heating unit 3 to heat the working fluid and eliminate icing. When the temperature sensor 10 receives a signal that is more than 2°C higher than the freezing point, the anti-freeze heating unit 3 stops working.

[0050] like Figure 6 Discharge status: When the system stops working and it is necessary to discharge the remaining working fluid in the phase change evaporator 1, the discharge device 7 is opened, and the residual working fluid flows out from the liquid discharge port 1-3 of the phase change evaporator 1, and is discharged to the system liquid discharge port C through the inlet 7-1 and outlet 7-2 of the discharge device.

[0051] like Figure 7Liquid level alarm status: Liquid level sensor 11 transmits the liquid level signal to control unit 8. When the liquid level signal is lower than the lower limit threshold, the controller will upload a "low liquid level" signal. The host computer of the airborne system controls the heating device to cut off the power, and heat source A no longer inputs heat into the system.

[0052] like Figure 8 Adding status: Before the system starts working, phase change working medium needs to be added into the phase change evaporator 1. The phase change working medium is added into the phase change evaporator 1 through the ground adding equipment connected to the adding port 1-4 of the phase change evaporator 1 until the liquid level reaches the highest level.

[0053] This invention is applicable to heat dissipation of high-power equipment. The system configuration can be adjusted according to heat exchange requirements, and the type of phase change working fluid can be adjusted according to the temperature control range requirements.

[0054] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A phase change heat transfer system controlled by negative pressure, characterized in that, The application relates to a phase-change evaporation device, which comprises the following components: a phase-change evaporation device (1) storing a phase-change working medium, which absorbs heat to reduce the temperature of a working medium in a heat exchange unit through phase change; a heat exchange unit (2) forming a circulating loop with a heat dissipation device, which transfers heat through the working medium; a freeze-proof heating unit (3) for heating the phase-change working medium in the phase-change evaporation device (1) to prevent the working medium from freezing under a too low temperature condition; a vacuum generator (5) for applying negative pressure to the phase-change evaporation device (1) to reduce the saturation temperature of the phase-change working medium; a control unit (8) for detecting the temperature, pressure and liquid level in the phase-change evaporation device (1) through sensors and adjusting the vacuum degree in the phase-change evaporation device (1) according to control requirements, and starting the freeze-proof heating unit (3) before the freezing temperature is reached.

2. The negative pressure controlled phase change heat transfer system of claim 1, wherein, The phase-change evaporation device (1) is provided with: an emergency pressure relief port (1-1) for overpressure relief; an exhaust port (1-2) connected to a vacuum generator working medium inlet (5-1) of the vacuum generator (5); a liquid discharge port (1-3) connected to a discharge device (7) for discharging residual phase-change working medium in the phase-change evaporation device (1); a filling port (1-4) for supplementing the phase-change working medium.

3. The negative pressure controlled phase change heat transfer system of claim 1, wherein, An emergency pressure relief unit (4) is further included, a pressure relief inlet (4-1) of the emergency pressure relief unit (4) is connected to the emergency pressure relief port (1-1), the emergency pressure relief valve (4) is a mechanical safety mechanism, when the pressure in the phase-change evaporation device (1) exceeds a threshold value, the pressure relief channel is automatically opened, and gas flows from the emergency pressure relief port (1-1) to the pressure relief outlet (4-2) through the pressure relief inlet (4-1) and is discharged into the environment.

4. The negative pressure controlled phase change heat transfer system of claim 1, wherein, The start and stop of the freeze-proof heating unit (3) are controlled by the control unit (8) according to the temperature sensor (10) signal: the heating is started when the temperature is lower than the freezing point of the working medium; and the heating is stopped when the temperature is higher than the freezing point by 2 DEG C.

5. The negative pressure controlled phase change heat transfer system of claim 1, wherein, The control unit (8) executes liquid level protection logic: when a liquid level meter (11) placed in the phase-change evaporation device (1) detects that the liquid level is lower than a lower threshold value, an alarm signal is sent to an upper computer and the power supply of the heat dissipation device is cut off.

6. The negative pressure controlled phase change heat transfer system of claim 1, wherein, The vacuum generator (5) is connected with a gas source regulating valve (6), when the pressure sensor (9) in the phase-change evaporation device (1) tests data higher than a set value, the control unit (8) opens the gas source regulating valve (6), the vacuum generator (5) generates negative pressure through high-pressure gas of the gas source regulating valve (6) to suck the gas in the phase-change evaporation device (1).

Images