Loop heat pipe aircraft equipment bay heat sink incorporating phase change material

Abstract

The application provides a loop heat pipe type aircraft equipment cabin heat dissipation device combined with a phase change material, which comprises an evaporator 1, a condenser 2, a phase change material 3, a liquid storage tank 4, an air storage tank 5, a liquid pump 6, a temperature sensor 7, a liquid pipeline 8, a steam pipeline 9, an axial flow fan 10, an air bypass valve 11, a liquid bypass valve 12, a check valve 13, a controller 14 and fins 15, wherein the evaporator 1 absorbs heat generated by equipment, the condenser 2 dissipates heat, and the phase change material 3 absorbs heat shock energy generated by equipment during short-time high-power operation; the controller 14 is connected with the liquid pump 6, the temperature sensor 7, the axial flow fan 10, the air bypass valve 11 and the liquid bypass valve 12; the evaporator 1 and the phase change material 3 form a heat dissipation base, and the heat generated by equipment is absorbed through the heat absorption surface on the upper surface of the evaporator; the condenser 2 and the fins 15 form a skin radiator, and heat is dissipated to ram air entering the skin radiator.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aircraft equipment cabin heat dissipation, in particular to a loop heat pipe type aircraft equipment cabin heat dissipation device combined with phase change material. BACKGROUND

[0002] Short-time high-power operation of some special electronic devices in an aircraft often causes a sharp rise in temperature, which may lead to device failure and safety accidents, which puts higher requirements on the device temperature control system. Aircraft electronic device heat dissipation technologies mainly include forced air cooling, traditional liquid cooling, heat pipe cooling, micro-channel cooling, phase change material heat storage, etc. With the increasing complexity of aircraft electronic device operating conditions, single cooling technology is increasingly difficult to meet the requirements of multi-condition operation, and composite cooling technology has gradually become a research hotspot. In addition, the existing air-air skin radiator and air-liquid skin radiator have low heat dissipation efficiency, large space occupation, and consume a large amount of ram air, resulting in large aircraft aerodynamic resistance and compensation loss. SUMMARY

[0003] Loop heat pipes, as a kind of high-efficiency heat transfer element, have very strong heat transport capacity; at the same time, phase change materials can absorb a large amount of heat and maintain a relatively constant temperature, and can better alleviate the short-time thermal shock of electronic devices when applied to the field of electronic device heat dissipation. The present application provides a loop heat pipe type aircraft equipment cabin heat dissipation device combined with phase change material, which can effectively inhibit the sharp rise in temperature of the device and the heat dissipation base.

[0004] Technical scheme: A loop heat pipe type aircraft equipment cabin heat dissipation device combined with phase change material, the device comprises an evaporator 1, a condenser 2, a phase change material 3, a liquid storage tank 4, a gas storage tank 5, a liquid pump 6, a temperature sensor 7, a liquid pipeline 8, a vapor pipeline 9, an axial flow fan 10, an air bypass valve 11, a liquid bypass valve 12, a check valve 13, a controller 14, and fins 15, wherein:

[0005] The evaporator 1 absorbs the heat generated by the equipment, the condenser 2 dissipates heat, and the phase change material 3 absorbs the thermal shock energy generated during the short-time high-power operation of the equipment; the controller 14 is connected with the liquid pump 6, the temperature sensor 7, the axial flow fan 10, the air bypass valve 11, and the liquid bypass valve 12; the evaporator 1 and the phase change material 3 constitute a heat dissipation base, which absorbs the heat generated by the equipment through the heat absorption surface on the upper surface of the evaporator 1; the condenser 2 and the fin 15 constitute a skin radiator, the high-temperature steam in the condenser 2 exchanges heat with the ram air entering the skin radiator and is cooled into liquid, and the fin 15 strengthens the heat dissipation effect; a bypass air channel is arranged beside the skin radiator, when the amount of ram air is insufficient, the axial flow fan 10 and the bypass air valve 11 are opened to suck sufficient air into the skin radiator; a bypass liquid channel is arranged beside the liquid pump 6, the bypass liquid channel is provided with a liquid bypass valve 12, the bypass valve 12 is closed when the liquid pump 6 is turned on, and the bypass valve 12 is opened when the liquid pump 6 is turned off, so as to ensure the heat dissipation effect of the system under different working conditions; the controller 14 monitors the ram air temperature and the equipment temperature by using the temperature sensor 7, and controls the start-stop of the liquid pump 6 and the axial flow fan 10 and the opening-closing of the air bypass valve 11 and the liquid bypass valve 12.

[0006] Specifically, the evaporator 1 is embedded in the phase change material 3 shell, the upper surface of the evaporator 1 is filled with heat-conducting silicone grease at the contact part with the electronic equipment to enhance the heat conduction capacity between them, and the remaining surfaces of the evaporator 1 are provided with fins 15 to enhance the heat exchange capacity of the evaporator 1 and the phase change material 3; the inside of the evaporator 1 is sequentially provided with a liquid cavity 16, a capillary core 17, and a steam cavity 18 from left to right, and a liquid channel 19 is arranged in the capillary core.

[0007] Specifically, the condenser 2 is arranged between the upper and lower surfaces of the skin, and is connected through the fins 15, and the fins 15 form a ram air channel.

[0008] Specifically, the evaporator 1, the condenser 2, the liquid tank 4, the air tank 5, the liquid pump 6, the liquid pipeline 8, the steam pipeline 9, the liquid bypass valve 12, and the check valve 13 constitute a loop heat pipe, and the working medium in the loop heat pipe includes water, FC-72, ethanol, acetone, R123, and R141b.

[0009] Specifically, the phase change material 3 includes organic phase change materials, inorganic phase change materials, and organic-inorganic composite phase change materials.

[0010] Specifically, the working process under normal conditions is as follows: the liquid pump 6 is closed, the liquid bypass valve 12 is opened, and the loop is driven to operate by the capillary force of the capillary wick 17 in the evaporator 1 and the density difference of the working medium in the evaporator 1 and the condenser 2; the liquid working medium in the liquid pipeline 8 is first introduced into the evaporator 1 to absorb heat and then evaporated into a gaseous state, the steam generated by each branch evaporator is collected in the gas storage tank 5, the steam enters the condenser 2 through the steam pipeline 9 under the action of the density difference, exchanges heat with the ram air and is cooled into a liquid, enters the liquid storage tank 4 through the check valve 13, then passes through the liquid bypass valve 12 and enters the evaporator 1 again to complete the cycle, and the liquid pump 6 is always closed.

[0011] Specifically, when the aircraft is flying at low altitude and low Mach number or the cabin environment temperature is relatively high, the ram pressure generated by the aircraft itself cannot provide sufficient ram air or the temperature difference between the equipment and the cabin environment is small, and the working process is as follows: the air bypass valve 11 is opened, sufficient ram air is driven by the axial flow fan 10 to exchange heat with the condenser 2, the liquid bypass valve 12 is closed, and the liquid pump 6 is opened to drive the flow of the working medium in the loop to prevent backflow or dry burning.

[0012] Specifically, when the equipment suddenly runs at high power, the heat generated increases sharply, and the loop heat pipe may not be able to dissipate the excess heat in a short time, and the working process is as follows: the temperature of the electronic equipment rises, the phase change material 3 around the evaporator 1 reaches the melting point temperature, the phase change material 3 changes phase, absorbs a large amount of heat and maintains a relatively stable temperature, effectively inhibiting the rapid rise of the temperature of the equipment and the heat dissipation base; after the electronic equipment runs normally or stops running, the heat is dissipated by the loop heat pipe.

[0013] In summary, the present application provides a loop heat pipe type aircraft equipment cabin heat dissipation device combined with phase change material, which absorbs the heat dissipation of the electronic equipment and cools down by using ram air in the skin radiator. When the aircraft is flying at low altitude and low Mach number or the cabin environment temperature is relatively high, the bypass air channel can be opened to suck ram air; when the equipment runs at high power, the phase change material changes phase to absorb and store heat, effectively inhibiting the rapid rise of the temperature of the equipment and the heat dissipation base. BRIEF DESCRIPTION OF DRAWINGS

[0014] The present application will be further described and illustrated below with reference to the accompanying drawings:

[0015] Figure 1 A system diagram of the loop heat pipe type aircraft equipment cabin heat dissipation device combined with phase change material provided by the present application is shown in the figure;

[0016] Figure 2 A schematic diagram of the heat dissipation base provided by the present application is shown in the figure;

[0017] Figure 3 This is a schematic diagram of a skinned radiator structure provided in this application.

[0018] Wherein: 1—Evaporator, 2—Condenser, 3—Phase Change Material, 4—Liquid Storage Tank, 5—Gas Storage Tank, 6—Liquid Pump, 7—Temperature Sensor, 8—Liquid Pipeline, 9—Steam Pipeline, 10—Axial Flow Fan, 11—Air Bypass Valve, 12—Liquid Bypass Valve, 13—Check Valve, 14—Controller, 15—Fin, 16—Liquid Chamber, 17—Capillary Core, 18—Steam Chamber, 19—Liquid Channel. Detailed Implementation

[0019] Example 1

[0020] like Figure 1 As shown, this invention provides a heat dissipation device combining a composite heat dissipation base for an equipment compartment with a skin radiator. The device includes an evaporator 1, a condenser 2, a phase change material 3, a liquid storage tank 4, a gas storage tank 5, a liquid pump 6, a temperature sensor 7, a liquid pipeline 8, a steam pipeline 9, an axial flow fan 10, an air bypass valve 11, a liquid bypass valve 12, a check valve 13, a controller 14, and fins 15, wherein:

[0021] like Figure 1 As shown, evaporator 1 absorbs the heat generated by the equipment, condenser 2 dissipates heat, and phase change material 3 absorbs the thermal shock energy generated during short-term high-power operation of the equipment. Controller 14 is connected to liquid pump 6, temperature sensor 7, axial fan 10, air bypass valve 11, and liquid bypass valve 12. Evaporator 1 and phase change material 3 form a heat dissipation base, absorbing the heat generated by the equipment through the heat-absorbing surface of the evaporator's upper surface. Condenser 2 and fins 15 form a skin radiator, where high-temperature steam in the condenser exchanges heat with the rammed air entering the skin radiator and is cooled into liquid. Fins 15 enhance the heat dissipation effect. A bypass air channel is provided next to the skin radiator. When the rammed air volume is insufficient, the axial fan 10 and bypass air valve 11 are opened to draw sufficient air into the skin radiator. A bypass liquid channel is provided next to liquid pump 6, and a liquid bypass valve 12 is installed on the bypass liquid channel. When liquid pump 6 is turned on, bypass valve 12 is closed; when liquid pump 6 is turned off, bypass valve 12 is opened to ensure the system's heat dissipation effect under different operating conditions. The controller 14 uses the temperature sensor 7 to monitor the temperature of the pressurized air and the equipment temperature, and controls the start and stop of the liquid pump 6 and the axial fan 10, as well as the opening and closing of the air bypass valve 11 and the liquid bypass valve 12.

[0022] like Figure 2As shown, the evaporator 1 is embedded in the housing of the phase change material 3. The upper surface of the evaporator 1, where it contacts the electronic device, is filled with thermally conductive silicone grease to enhance the thermal conductivity between the two. The remaining surfaces of the evaporator 1 are provided with fins 15 to enhance the heat exchange capacity between the evaporator 1 and the phase change material 3. The interior of the evaporator 1, from left to right, consists of a liquid chamber 16, a capillary wick 17, and a vapor chamber 18. A liquid channel 19 is provided in the capillary wick.

[0023] like Figure 3 As shown, the condenser 2 is disposed between the upper and lower surfaces of the skin and is connected by fins 15, forming a ram air channel between the fins 15.

[0024] It should be noted that the position of evaporator 1 can be flexibly arranged, with multiple evaporator branches connected in series or parallel. The steam generated by evaporator 1 first collects in the gas storage tank 5, and then enters the condenser 2 for cooling through the steam pipeline 9 under the action of density difference. The position of condenser 2 can also be flexibly arranged, utilizing the capillary force generated by the capillary wick 17 inside evaporator 1 and the density difference of the working fluid in evaporator 1 and condenser 2 to drive the circuit operation, which is not limited by height difference, thus allowing for the use of a larger skin area for heat dissipation.

[0025] Specifically, the evaporator 1, condenser 2, liquid storage tank 4, gas storage tank 5, liquid pump 6, liquid pipeline 8, steam pipeline 9, liquid bypass valve 12, and check valve 13 form a loop heat pipe. The working fluid in the loop heat pipe includes water, FC-72, ethanol, acetone, R123, and R141b.

[0026] Specifically, phase change materials 3 include organic phase change materials (such as paraffin, fatty acids, alcohols, etc.), inorganic phase change materials (such as hydrated salts, elemental salts), and organic-inorganic composite phase change materials.

[0027] Specifically, the normal operating process is as follows: the liquid pump 6 is turned off, the liquid bypass valve 12 is opened, and the loop operation is driven by the capillary force of the capillary wick 17 in the evaporator 1 and the density difference of the working fluid in the evaporator 1 and the condenser 2. The liquid working fluid in the liquid pipeline 8 first enters the evaporator 1 to absorb heat and then evaporates into a gaseous state. The steam generated by each branch evaporator is collected in the gas storage tank 5. Under the action of the density difference, the steam enters the condenser 2 through the steam pipeline 9, exchanges heat with the rammed air and is cooled into a liquid. After passing through the check valve 13, it enters the liquid storage tank 4, and then enters the evaporator 1 again through the liquid bypass valve 12 to complete the cycle. The liquid pump 6 is always in the off state.

[0028] Specifically, when the aircraft is flying at low altitude and low Mach number or the temperature of the outboard environment is high, the ram air generated by the aircraft itself cannot provide sufficient ram air or the temperature difference between the equipment and the outboard environment is small, and the working process is: opening the air bypass valve 11, using the axial flow fan 10 to drive sufficient ram air to exchange heat with the condenser 2, at the same time closing the liquid bypass valve 12, opening the liquid pump 6, and driving the working fluid in the loop to flow, preventing the phenomenon of backflow or dry burning.

[0029] Specifically, when the equipment suddenly runs at high power consumption, the heat generated increases dramatically, and the loop heat pipe may not be able to dissipate the excess heat in a short time, and the working process is: the temperature of the electronic equipment rises, so that the phase change material 3 around the evaporator 1 reaches the melting point temperature, the phase change material 3 changes phase, absorbs a large amount of heat and maintains a relatively stable temperature, effectively inhibiting the rapid rise of the temperature of the equipment and the heat dissipation base; after the electronic equipment runs normally or stops running, the heat is dissipated by the loop heat pipe.

[0030] Example two

[0031] The temperature of the electronic equipment of the aircraft is generally controlled below 60°C, and for an equipment cabin with a heat dissipation of 20kW, the heat flux density of the loop heat pipe evaporator is about 100W / cm 2 , the heat flux density of the condenser is about 5kW / m 2 , the evaporator area of the heat pipe is 200cm 2 , and the condenser area is 4m 2 , which can meet the requirements, and the required air-cooled radiator area under the same working condition is about 30m 2 . The phase change material is paraffin with a phase change temperature of 60°C and a melting latent heat of 176kJ / kg. The controller controls the temperature difference between the evaporator and the condenser to be above 20°C.

[0032] Under normal conditions, the temperature of the liquid working medium entering the evaporator 1 is controlled between 5-25°C, the liquid working medium enters the liquid chamber 16 in the evaporator 1 through the liquid pipeline 8, is absorbed in the liquid channel 19 by the capillary core 17, the heat absorption surface on the upper surface of the evaporator 1 absorbs the heat generated by the equipment, the liquid working medium in the capillary core 17 absorbs heat and changes into gas, enters the vapor chamber 18, the vapor generated by each evaporator branch enters the storage tank 5 under the action of density difference, enters the condenser 2 through the vapor pipeline 9, exchanges heat with the ram air in the skin radiator and is cooled again to liquid, enters the liquid pipeline 8, enters the liquid storage tank 4 after passing through the check valve 13, then enters the evaporator 1 again through the liquid bypass valve 12 to complete the cycle, and the liquid pump 6 is always in the closed state. The whole process does not require external power.

[0033] When the cabin external environment air temperature is higher or the aircraft low altitude, low Mach number flight, ram air is insufficient, resulting in equipment and ram air temperature difference less than 20 DEG C, then open air bypass valve 11, using axial flow fan 10 suction cabin external air, the working medium in the loop heat pipe cooling, while closing liquid bypass valve 12, open body liquid pump 6, drive loop heat pipe operation, avoid the appearance of reverse flow or dry phenomenon.

[0034] When the equipment power consumption suddenly increases, the heat dissipation increases by 1%, which can cause the cabin temperature to rise by about 1.8 DEG C per minute, and if the phase change melting point temperature of the paraffin is 60 DEG C, when the paraffin mass is 10 kg, the heat absorption capacity is about 2031 kJ after complete melting, which can maintain the equipment cabin temperature within 170 minutes.

[0035] Technical effects:

[0036] Based on the scheme, the heat dissipation device has the advantages of high heat transfer efficiency, good heat dissipation effect, easy installation, and is suitable for various complex working conditions, and the like.

[0037] 1. The aircraft equipment cabin heat dissipation device is a composite cooling device, which can alleviate the problem that the traditional single cooling mode such as liquid cooling and forced air cooling is limited by the heat transfer limit, and better guarantees the temperature stability of the equipment. The loop heat pipe has high heat transfer rate and does not need external power, and has strong heat transport capacity; at the same time, the phase change material has light weight, large heat absorption capacity and good thermal stability, and the temperature is relatively constant during phase change, which can absorb the overload heat generated by electronic equipment, greatly relieve short-time thermal stress and thermal shock, and can better meet the temperature control demand of electronic equipment.

[0038] 2. The loop heat pipe has the characteristics of small volume, good anti-gravity performance, flexible installation angle and position, etc., and can be flexibly arranged in the complex and small aircraft equipment cabin to absorb heat through multiple series or parallel evaporator branches. The condenser of the loop heat pipe is connected with the fin to form a skin radiator, which has higher heat dissipation efficiency and requires less ram air than the conventional air-air skin radiator and air-liquid skin radiator, thereby reducing the aerodynamic resistance and compensation loss of the aircraft.

[0039] 3. Under normal working conditions, the operation of the heat dissipation system does not need any power, and the loop is driven to operate under the action of the capillary force generated by the capillary core in the evaporator and the density difference of the working medium in the evaporator and the condenser, thereby saving the system operation energy consumption. In severe working environment, the axial flow fan and the liquid pump can be opened to strengthen the condensation heat dissipation effect and ensure the normal flow of the loop working medium, and the phase change material can be used to absorb the heat shock energy generated by the equipment, thereby meeting the heat dissipation demand under various complex working conditions.

Claims

1. A loop heat pipe type heat dissipation device for aircraft equipment compartments incorporating phase change materials, characterized in that, The device includes an evaporator (1), a condenser (2), a phase change material (3), a liquid storage tank (4), a gas storage tank (5), a liquid pump (6), a temperature sensor (7), a liquid pipeline (8), a steam pipeline (9), an axial fan (10), an air bypass valve (11), a liquid bypass valve (12), a check valve (13), a controller (14), and fins (15), wherein: Evaporator (1) absorbs the heat generated by the equipment, condenser (2) dissipates the heat, and phase change material (3) absorbs the thermal shock energy generated during short-term high-power operation of the equipment; controller (14) is connected to liquid pump (6), temperature sensor (7), axial fan (10), air bypass valve (11), and liquid bypass valve (12); evaporator (1) and phase change material (3) form a heat dissipation base, absorbing the heat generated by the equipment through the heat absorption surface on the upper surface of the evaporator; condenser (2) and fins (15) form a skin radiator, the high-temperature steam in condenser (2) exchanges heat with the rammed air entering the skin radiator and is cooled into liquid, and fins (15) enhance the heat dissipation effect; a bypass air channel is set next to the skin radiator, and when the amount of rammed air is insufficient, the axial fan (6) is turned on. 10) With the air bypass valve (11), sufficient air is drawn into the skin radiator; a bypass liquid channel is set next to the liquid pump (6), and a liquid bypass valve (12) is set on the bypass liquid channel. When the liquid pump (6) is turned on, the liquid bypass valve (12) is closed, and when the liquid pump (6) is turned off, the liquid bypass valve (12) is opened to ensure the heat dissipation effect of the system under different working conditions; the controller (14) uses the temperature sensor (7) to monitor the temperature of the pressurized air and the equipment temperature, and controls the start and stop of the liquid pump (6), the axial fan (10), and the opening and closing of the air bypass valve (11) and the liquid bypass valve (12); the evaporator (1) has a liquid chamber (16), a capillary core (17), and a steam chamber (18) from left to right, and a liquid channel (19) is set in the capillary core; The normal working process is as follows: The liquid pump (6) is turned off, and the liquid bypass valve (12) is opened. The loop is driven by the capillary force of the capillary core (17) in the evaporator (1) and the density difference between the working fluid in the evaporator (1) and the condenser (2). The liquid working fluid in the liquid pipeline (8) first enters the evaporator (1) to absorb heat and then evaporates into a gaseous state. The steam generated by each branch evaporator is collected in the gas storage tank (5). Under the action of the density difference, the steam enters the condenser (2) through the steam pipeline (9), exchanges heat with the pressurized air and is cooled into a liquid. After passing through the check valve (13), it enters the liquid storage tank (4) and then enters the evaporator (1) again through the liquid bypass valve (12) to complete the cycle. The liquid pump (6) is always in the off state. When the aircraft is flying at low altitudes and low Mach numbers, or when the external ambient temperature is high, the operating process is as follows: Open the air bypass valve (11), and use the axial fan (10) to drive a sufficient amount of compressed air to exchange heat with the condenser (2). At the same time, close the liquid bypass valve (12), turn on the liquid pump (6), and drive the working fluid in the loop to flow. When the device suddenly operates at high power consumption, the working process is as follows: The temperature of the electronic device rises, causing the phase change material (3) around the evaporator (1) to reach its melting point. The phase change material (3) undergoes a phase change, absorbs a large amount of heat, and maintains a relatively stable temperature. After the electronic device is running normally or stops running, the heat is dissipated by the loop heat pipe.

2. The loop heat pipe type aircraft equipment compartment heat dissipation device according to claim 1, characterized in that, Evaporator (1) is embedded in the shell of phase change material (3). The upper surface of evaporator (1) is filled with thermal grease at the contact point with electronic equipment to enhance the thermal conductivity between the two. The remaining surface of evaporator (1) is provided with fins (15) to enhance the heat exchange capacity between evaporator (1) and phase change material (3).

3. The loop heat pipe type aircraft equipment compartment heat dissipation device according to claim 1, characterized in that, The condenser (2) is located between the upper and lower surfaces of the skin and is connected by fins (15), forming a ram air channel between the fins (15).

4. The loop heat pipe type aircraft equipment compartment heat dissipation device according to claim 1, characterized in that, An evaporator (1), a condenser (2), a liquid storage tank (4), a gas storage tank (5), a liquid pump (6), a liquid pipeline (8), a steam pipeline (9), a liquid bypass valve (12), and a check valve (13) form a loop heat pipe. The working fluid in the loop heat pipe includes water, FC-72, ethanol, acetone, R123, and R141b.

5. The loop heat pipe type aircraft equipment compartment heat dissipation device according to claim 1, characterized in that, Phase change materials (3) include organic phase change materials, inorganic phase change materials, and organic-inorganic composite phase change materials.

Images