An integrated aircraft thermal management system based on low-pressure flash spray technology

Abstract

The present invention proposes an integrated aircraft thermal management system based on low-pressure flash spray technology, belonging to the field of aircraft thermal management. This system solves the problem of requiring an additional heat sink to cool high-heat-flux-density components in aircraft using low-pressure flash spray. The system comprises a low-pressure flash spray cooling system, a compression refrigeration system, and a fuel circulation system. The low-pressure flash spray cooling system is connected to the compression refrigeration system, which is in turn connected to the fuel circulation system. The compression refrigeration system is used to transfer heat from high-heat-flux-density components in the low-pressure flash spray cooling system to the fuel circulation system. This system can utilize fuel as a heat sink to gradiently remove heat from high- and low-heat-flux-density components, reducing mass penalties.

Description

Technical Field

[0001] The present invention belongs to the field of aircraft thermal management, and in particular relates to an integrated aircraft thermal management system based on low-pressure flash spray technology. Background Art

[0002] As aircraft electronics continue to demand higher technology, airborne radars, laser diode arrays, electrically driven brakes, and satellite electronics are trending towards miniaturization, modularization, and high integration. This complicates heat dissipation. The reduction in heat dissipation area leads to a sharp increase in the heat flux density of heating components, sometimes exceeding 200W / cm². This heat dissipation, previously sufficient with air cooling, now requires more powerful cooling methods, such as spray cooling and microchannel cooling. Furthermore, while carrying an additional heat sink onboard can meet the cooling needs of the equipment, the resulting mass penalty is significant. Therefore, maximizing the integration of system heat flow within the existing fuel heat sink has become a top priority.

[0003] In existing aircraft, spray cooling has been applied to thermal management systems. However, with the increase in heat flux density, traditional spray cooling technology also faces challenges. The low-pressure flash spray cooling system has a lower evaporation temperature. Once the atomized coolant leaves the nozzle, the coolant is in a superheated state. In this state, flash evaporation or boiling will occur, accompanied by the rapid rupture of the droplet mass, which helps the subsequent breakup of the droplets. This is called the secondary breakup process, which is mainly caused by the rapid generation of huge bubbles inside the superheated droplets. Traditional non-flash / boiling spray droplets also have a secondary breakup process, which is attributed to the relative motion between the high-speed droplets and the surrounding air. The secondary breakup process of the low-pressure flash spray cooling system is more intense and the heat exchange capacity is stronger. Therefore, low-pressure spray cooling technology has more advantages in the thermal management of high heat flux density components in aircraft.

[0004] In addition, in addition to fuel and external air, many aircraft will carry some heat sinks into the aircraft, such as water, liquid nitrogen, dry ice, etc. Although this can solve the problem of insufficient heat sinks in the aircraft to a certain extent, it will bring serious quality penalties. Therefore, designing a thermal management system that does not use additional heat sinks and can cooperate with a low-pressure flash spray cooling system to complete heat exchange has become an urgent problem to be solved. Summary of the Invention

[0005] In view of this, the present invention aims to propose an integrated aircraft thermal management system based on low-pressure flash spray technology to solve the problem that additional heat sinks are required to cool high heat flux density components in aircraft using low-pressure flash spray.

[0006] To achieve the above objectives, the present invention adopts the following technical solutions: an integrated aircraft thermal management system based on the low-pressure flash spray principle, comprising a low-pressure flash spray cooling system, a compression refrigeration system, and a fuel circulation system, wherein the low-pressure flash spray cooling system is connected to the compression refrigeration system, which is in turn connected to the fuel circulation system, and the compression refrigeration system is used to transfer heat from high heat flux density components in the low-pressure flash spray cooling system to the fuel circulation system;

[0007] The low-pressure flash spray cooling system includes an evaporator, a coolant tank, a high-pressure pump, a venturi tube, a nozzle and a low-pressure spray chamber. The outlet end of the coolant tank is connected to one end of the drainage tube, and the other end of the drainage tube is connected to the nozzle. The drainage tube is provided with a high-pressure pump, and the nozzle extends into the low-pressure spray chamber. The outlet end of the low-pressure spray chamber is connected to the inlet of the adsorption chamber in the back-pressure zone of the venturi tube. A branch pipeline is provided on the drainage tube between the high-pressure pump and the nozzle. The branch pipeline is connected to the high-pressure fluid inlet on the venturi tube. The liquid entering the venturi tube through the high-pressure fluid inlet forms an attraction on the inlet of the adsorption chamber in the back-pressure zone, so that low pressure is formed in the low-pressure spray chamber. The outlet of the venturi tube is connected to the hot end inlet of the evaporator, and the hot end outlet of the evaporator is connected to the reflux port of the coolant tank.

[0008] Furthermore, a flow regulating valve is provided on the branch pipeline.

[0009] Furthermore, the opening of the flow regulating valve is between 0-1.

[0010] Furthermore, a nozzle connected to the high-pressure fluid inlet is provided in the venturi tube, and the cross-sectional area of the inlet end of the nozzle is larger than that of the outlet end.

[0011] Furthermore, the compression refrigeration system includes a compressor, a throttle valve and a condenser, the outlet of the compressor is connected to the hot end inlet of the condenser, the hot end outlet of the condenser is connected to the cold end inlet of the evaporator through the throttle valve, and the cold end outlet of the evaporator is connected to the inlet of the compressor.

[0012] Furthermore, the fuel loop system includes a fuel tank, a heat exchange pipe and an oil pump. The outlet end of the fuel tank is connected to the cold end inlet of the condenser through the oil pump. The fuel in the fuel tank is drained into the condenser through the oil pump for heat exchange and then output from the cold end outlet of the condenser.

[0013] Furthermore, a microchannel radiator is provided in the fuel circulation system, and the microchannel radiator is arranged between the fuel tank and the fuel pump. The outlet end of the fuel tank is connected to the inlet end of the microchannel radiator, and the outlet end of the microchannel radiator is connected to the inlet end of the pump.

[0014] Furthermore, the high heat flux density element is arranged in the low-pressure spray chamber, and the microchannel radiator is used to cool the low heat flux density element.

[0015] Furthermore, the nozzle is made of stainless steel, the spray angle of the nozzle is 120°, and the distance from the nozzle to the heating surface of the high heat flux density element is 10 mm.

[0016] Furthermore, the coolant in the coolant tank is water or refrigerant.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The coolant in the coolant tank is divided into two streams by a high-pressure pump. One stream is directed to the nozzle to form a spray to cool the high heat flux density component, and the other stream enters the Venturi tube to form a high-pressure liquid that attracts the back pressure of the Venturi tube, thereby helping to form a low pressure in the low-pressure spray chamber. The heat exchange is carried out by using the effect of low-pressure flash evaporation to achieve better heat exchange effect.

[0019] 2. The mixed liquid after heat exchange is discharged through the compression refrigeration system, and the coolant flows back into the coolant tank for recycling;

[0020] 3. The heat is ultimately transferred to the fuel in the oil circuit through the compression refrigeration system, thereby achieving the effect of ultimately transferring the heat away;

[0021] 4. The process of fuel being drawn out of the fuel tank can quickly take away the heat of the low heat flux density components through the microchannel radiator, and then enter the condenser to take away the heat of the refrigerant, forming a gradient utilization of the heat sink and improving the utilization rate of the fuel heat sink. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0023] Figure 1 This is a schematic structural diagram of an integrated aircraft thermal management system based on low-pressure flash spray technology according to the present invention;

[0024] Figure 2 Schematic diagram of the structure of the Venturi tube of the present invention.

[0025] Low-pressure flash spray cooling system A; compression refrigeration system B; fuel loop system C; compressor 1; evaporator 2; throttle valve 3; condenser 4; coolant tank 5; high-pressure pump 6; venturi tube 7; flow regulating valve 8; nozzle 9; oil tank 10; microchannel radiator 11; oil pump 12; high-pressure fluid inlet 13; nozzle 14; adsorption chamber inlet 15; outlet 16; low-pressure spray chamber 17. DETAILED DESCRIPTION

[0026] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely explain the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present invention and the features therein can be combined with each other in the absence of conflict, and the embodiments described are only part of the embodiments of the present invention, not all of the embodiments.

[0027] Referring to the accompanying drawings, this embodiment is described. An integrated aircraft thermal management system based on low-pressure flash spray technology includes a low-pressure flash spray cooling system A, a compression refrigeration system B, and a fuel loop system C. The low-pressure flash spray cooling system A is connected to the compression refrigeration system B, which is in turn connected to the fuel loop system C. The compression refrigeration system B is used to transfer heat from high heat flux density components within the low-pressure flash spray cooling system A to the fuel loop system C.

[0028] The low-pressure flash spray cooling system A includes an evaporator 2, a coolant tank 5, a high-pressure pump 6, a venturi tube 7, a nozzle 9 and a low-pressure spray chamber 17. The outlet end of the coolant tank 5 is connected to one end of the drainage pipe, and the other end of the drainage pipe is connected to the nozzle 9. The drainage pipe is provided with a high-pressure pump 6, and the nozzle 9 extends into the low-pressure spray chamber 17. The outlet end of the low-pressure spray chamber 17 is connected to the adsorption chamber inlet 15 of the back pressure zone of the venturi tube 7. A branch pipeline is provided on the drainage pipe between the high-pressure pump 6 and the nozzle 9. The branch pipeline is connected to the high-pressure fluid inlet 13 on the venturi tube 7. The liquid entering the venturi tube 7 through the high-pressure fluid inlet 13 forms an attraction on the adsorption chamber inlet 15 of the back pressure zone to form a low pressure in the low-pressure spray chamber 17. The outlet 16 of the venturi tube 7 is connected to the hot end inlet of the evaporator 2, and the hot end outlet of the evaporator 2 is connected to the reflux port of the coolant tank 5.

[0029] In this embodiment, a flow regulating valve 8 is provided on the branch pipeline. The opening of the flow regulating valve 8 is adjusted between 0-1, which can change the size of the refrigerant liquid flow through the venturi tube 7 and adjust the vacuum degree in the spray chamber.

[0030] In this embodiment, a nozzle 14 communicating with a high-pressure fluid inlet 13 is provided in the venturi tube 7 . The cross-sectional area of the inlet end of the nozzle 14 is larger than that of the outlet end, so that the fluid can be accelerated.

[0031] In this embodiment, the compression refrigeration system B includes a compressor 1, a throttle valve 3 and a condenser 4. The outlet end of the compressor 1 is connected to the hot end inlet of the condenser 4, the hot end outlet of the condenser 4 is connected to the cold end inlet of the evaporator 2 through the throttle valve 3, and the cold end outlet of the evaporator 2 is connected to the inlet end of the compressor 1.

[0032] In this embodiment, the fuel loop system C includes a fuel tank 10, a heat exchange pipe and an oil pump 12. The outlet end of the fuel tank 10 is connected to the cold end inlet of the condenser 4 through the oil pump 12. The fuel in the fuel tank 10 is drained into the condenser 4 through the oil pump 12 for heat exchange and then output from the cold end outlet of the condenser 4.

[0033] In this embodiment, a microchannel radiator 11 is further provided in the fuel loop system C. The microchannel radiator 11 is used to cool low heat flux density components. The microchannel radiator 11 is arranged between the fuel tank 10 and the fuel pump 12. The outlet end of the fuel tank 10 is connected to the inlet end of the microchannel radiator 11, and the outlet end of the microchannel radiator 11 is connected to the inlet end of the pump 12.

[0034] In this embodiment, the nozzle 9 is made of stainless steel, the spray angle of the nozzle 9 is 120°, and the distance from the nozzle to the heating surface of the high heat flux density component is 10 mm, which improves the cooling effect.

[0035] In this embodiment, the coolant in the coolant tank 5 is water or refrigerant.

[0036] During use, the high-pressure pump 6 extracts the fluid in the coolant tank 5 and provides power for the nozzle 9 to spray. The fluid is divided into two parts. One part is sprayed into the low-pressure spray chamber through the nozzle 9. The temperature difference between the droplets sprayed from the nozzle 9 and the heating surface increases, thereby enhancing the heat exchange effect and cooling the high heat flux density component. The refrigerant droplets evaporate to form steam, and the other part of the fluid enters the venturi tube 7 through the flow regulating valve 8. After the liquid enters the venturi tube 7 from the high-pressure fluid inlet 13, the cross-sectional area of the nozzle 14 gradually narrows, which accelerates the fluid. According to the Bernoulli principle, there is a vacuum area at the inlet of the adsorption chamber, so that a low-pressure environment is created for the low-pressure spray chamber through the adsorption chamber inlet 15 located in the vacuum area, helping to recover the spray vapor after heat exchange, mix it with the liquid in the venturi tube 7, and then input it into the evaporator 2 together to exchange heat with the compression refrigeration system B, and then return it to the coolant tank 5 after heat exchange;

[0037] The heat exchange process of the compression refrigeration system B is that the refrigerant first absorbs the heat of the fluid flowing from the venturi tube 7 in the evaporator 2 and evaporates. After evaporation, it enters the compressor 1 and is pressurized to become a high-temperature and high-pressure gas. It then enters the condenser 4 to exchange heat with the fuel. The fuel is extracted from the oil tank 10 by the oil pump 12. When the oil passes through the microchannel radiator 11, it takes away the heat of the low heat flux density component and then enters the condenser 4 to exchange heat with the refrigerant to ensure the cascade utilization of the fuel heat sink. The refrigerant releases heat and becomes a high-pressure liquid. It then enters the throttle valve 3 to reduce pressure and finally enters the evaporator 2 again to absorb the heat of the coolant in the spray cooling system to complete the cycle. The role of the compression refrigeration cycle in this patent is to connect the low-pressure flash spray cooling system with the fuel loop to realize the function of reverse heat transfer. Due to the existence of the compression refrigeration system B, the fuel acts as a heat sink for cooling the low heat flux density component and the temperature entering the condenser 4 can be above 50°C. The channel width of the microchannel radiator 11 is about 100μm and the material is red copper.

[0038] The embodiments of the present invention disclosed above are intended only to illustrate the present invention. The embodiments do not describe all details in detail, nor do they limit the present invention to the specific embodiments described. Numerous modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention.

Claims

1. An integrated aircraft thermal management system based on the principle of low-pressure flash spray, characterized by: The system comprises a low-pressure flash spray cooling system, a compression refrigeration system and a fuel circulation system. The low-pressure flash spray cooling system is connected to the compression refrigeration system, which is in turn connected to the fuel circulation system. The compression refrigeration system is used to transfer heat from high heat flux density components in the low-pressure flash spray cooling system to the fuel circulation system. The low-pressure flash spray cooling system comprises an evaporator (2), a coolant tank (5), a high-pressure pump (6), a venturi tube (7), a nozzle (9) and a low-pressure spray chamber (17), wherein the outlet end of the coolant tank (5) is communicated with one end of a drainage pipe, the other end of the drainage pipe is connected to the nozzle (9), the drainage pipe is provided with a high-pressure pump (6), the nozzle (9) extends into the low-pressure spray chamber (17), the outlet end of the low-pressure spray chamber (17) is communicated with the adsorption chamber inlet (15) of the back pressure zone of the venturi tube (7), and the high-pressure A branch pipe is provided on the drainage pipe between the pump (6) and the nozzle (9), and the branch pipe is connected to the high-pressure fluid inlet (13) on the venturi tube (7). The liquid entering the venturi tube (7) through the high-pressure fluid inlet (13) forms an attraction force on the adsorption chamber inlet (15) of the back pressure zone, so that a low pressure is formed in the low-pressure spray chamber (17). The outlet (16) of the venturi tube (7) is connected to the hot end inlet of the evaporator (2), and the hot end outlet of the evaporator (2) is connected to the reflux port of the coolant tank (5).

2. The aircraft thermal management integrated system based on the low-pressure flash spray principle according to claim 1, characterized in that: A flow regulating valve (8) is provided on the branch pipeline.

3. The integrated aircraft thermal management system based on the low-pressure flash spray principle according to claim 2, characterized in that: The opening degree of the flow regulating valve (8) is between 0 and 1.

4. The integrated aircraft thermal management system based on the low-pressure flash spray principle according to claim 1, characterized in that: The venturi tube (7) is provided with a nozzle (14) in communication with the high-pressure fluid inlet (13), and the cross-sectional area of the inlet end of the nozzle (14) is larger than that of the outlet end.

5. An integrated aircraft thermal management system based on the low-pressure flash spray principle according to any one of claims 1 to 4, characterized in that: The compression refrigeration system comprises a compressor (1), a throttle valve (3) and a condenser (4); the outlet of the compressor (1) is connected to the hot end inlet of the condenser (4); the hot end outlet of the condenser (4) is connected to the cold end inlet of the evaporator (2) through the throttle valve (3); and the cold end outlet of the evaporator (2) is connected to the inlet of the compressor (1).

6. The integrated aircraft thermal management system based on the low-pressure flash spray principle according to claim 5, characterized in that: The fuel circulation system comprises a fuel tank (10), a heat exchange pipe and an oil pump (12); the outlet of the fuel tank (10) is connected to the cold end inlet of the condenser (4) via the oil pump (12); the fuel in the fuel tank (10) is guided into the condenser (4) by the oil pump (12) for heat exchange and then output from the cold end outlet of the condenser (4).

7. The integrated aircraft thermal management system based on the low-pressure flash spray principle according to claim 6, characterized in that: A microchannel radiator (11) is further provided in the fuel loop system. The microchannel radiator (11) is arranged between the fuel tank (10) and the fuel pump (12). The outlet end of the fuel tank (10) is communicated with the inlet end of the microchannel radiator (11), and the outlet end of the microchannel radiator (11) is communicated with the inlet end of the pump (12).

8. The integrated aircraft thermal management system based on the low-pressure flash spray principle according to claim 7, characterized in that: The high heat flux density element is arranged in the low-pressure spray chamber (17), and the microchannel radiator (11) is used to cool the low heat flux density element.

9. The aircraft thermal management integrated system based on the low-pressure flash spray principle according to claim 1, characterized in that: The nozzle (9) is made of stainless steel, the spray angle of the nozzle (9) is 120°, and the distance from the nozzle to the heating surface of the high heat flux density element is 10 mm.

10. The aircraft thermal management integrated system based on the low-pressure flash spray principle according to claim 1, characterized in that: The coolant in the coolant tank (5) is a refrigerant.

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