Variable altitude integrated thermal management system and method for an aero-piston engine based on pulsating heat pipe

Abstract

This invention discloses an integrated thermal management system and method for aero-engines based on pulsating heat pipes and varying altitudes. The system includes a closed-loop pulsating heat pipe network, an altitude-adaptive air duct, and a multi-functional auxiliary liquid cooling circuit. Based on the combustion knock mechanism, a pulsating heat pipe evaporation section is embedded in the cylinder block's knock-prone area. The ultra-high thermal conductivity of the working fluid during phase change instantly suppresses localized high-temperature hotspots, effectively inhibiting knock. The auxiliary liquid cooling circuit uses a proportional three-way flow control valve for intelligent regulation, enabling continuous on-demand distribution of coolant between auxiliary heat dissipation and waste heat utilization. The central control unit dynamically adjusts fan start / stop and speed based on flight speed and heat load. Combined with the ram effect of the Venturi air duct, it maximizes cruise energy consumption while ensuring takeoff / idle heat dissipation. A waste heat utilization and air conditioning co-heating strategy is adopted, compensating for insufficient waste heat with an auxiliary heating module, achieving flight safety and precise temperature control under wide-range variable operating conditions.

Description

Technical Field

[0001] This invention relates to the field of thermal management and environmental control technology for aero-engines, specifically to an integrated thermal management system and method for aero-engines based on pulsating heat pipes and varying altitudes. Background Technology

[0002] Aviation piston engines are widely used in general aviation aircraft and medium-to-large unmanned aerial vehicles. Compared with ground vehicle engines, aviation engines have a much wider operating envelope, and their thermal management systems face more stringent challenges.

[0003] Existing cooling technologies for aero-engine piston engines mainly face two traditional challenges: First, there is a contradiction between the difficulty of heat dissipation at high altitudes and the weight of the system: although traditional liquid cooling systems have stable temperature control, they include heavy water jackets, large radiators and coolant, which are "dead weight"; although air cooling systems are light, their heat dissipation capacity is drastically reduced at high altitudes and low Reynolds numbers.

[0004] Secondly, there is the risk of knocking under low-altitude, high-load conditions: During takeoff and climb, low airspeeds are common, making it easy for localized high-temperature hot spots to form near the cylinder block. These hot spots shorten the auto-ignition induction period of the final air-fuel mixture, inducing severe knocking, which can lead to engine damage in severe cases.

[0005] Furthermore, with the increasing electrification of aviation, existing thermal management systems are facing new challenges: Airborne small power batteries are extremely sensitive to temperature, with an optimal range of 20-30°C. Traditional systems typically lack adaptability to extreme contrasting operating conditions such as "low speed, high load" (climbing) and "high speed, low load" (dive). For example, during a climb, although there is a strong demand for heat dissipation, the low airspeed means that ram airflow alone is insufficient for cooling, leading to engine overheating; while during a dive, the high airspeed results in excessive cooling, and insufficient residual heat causes cabin cooling. Summary of the Invention

[0006] The main objective of this invention is to provide an integrated thermal management system and method for aero-engines based on pulsating heat pipes at varying altitudes, in order to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides an integrated thermal management system for variable altitude aero-engines based on a pulsating heat pipe, comprising: The engine body has microchannel evaporation channels in the high-heat-load, easily detonated area inside; The pulsating heat pipe circulation heat dissipation module is composed of multiple parallel capillary tubes connected end to end in a closed loop. The tubes are evacuated and filled with a gas-liquid two-phase working fluid. The capillary tubes include an evaporation section tightly embedded in a microchannel evaporation channel, an insulation section connecting the heat source and the cold source, a condensation section extending to the outside of the unit, and a pressure relief valve located on the high-pressure side of the capillary tubes. The variable altitude airflow adjustment module is located on the windward side of the fuselage and includes a Venturi acceleration tube section, an intake adjustment louver and an exhaust adjustment louver arranged sequentially in the Venturi acceleration tube section along the airflow direction; the condensation section is placed horizontally at the throat of the Venturi acceleration tube section to enhance heat transfer by utilizing the airflow acceleration effect. The multi-functional auxiliary active liquid cooling module includes a liquid storage tank, an electric water pump, a coupling heat exchanger, a proportional three-way flow regulating valve connected in series, and an auxiliary heat dissipation branch and a waste heat utilization branch connected in parallel. The coupling heat exchanger is thermally coupled and wrapped around the outside of the insulation section. The auxiliary heat dissipation branch is used to dissipate heat to the external environment. The waste heat utilization branch is used to blow heat into the engine compartment. The external fuselage is equipped with an air conditioning auxiliary heating module in the cabin heating duct to provide an active compensation heat source when the engine waste heat is insufficient. The central control unit is electrically connected to the intake regulating louvers, exhaust regulating louvers, electronic water pump, proportional three-way flow regulating valve, auxiliary heat dissipation branch, waste heat utilization branch and air conditioning auxiliary heating module, and receives signals from various sensors to perform multi-target coupled control.

[0008] As a further improvement of the present invention, the auxiliary heat dissipation branch includes an auxiliary heat sink and its matching electronic cooling fan, the electronic cooling fan being configured to force airflow for heat dissipation under ground idling or low-speed high-load conditions.

[0009] As a further improvement of the present invention, the waste heat utilization branch includes a cabin heating heat exchanger and a power battery insulation sleeve arranged in series; the cabin heating heat exchanger is equipped with a cabin blower for blowing heat into the cabin.

[0010] As a further improvement of the present invention, it also includes an altitude sensor, a cylinder head temperature sensor, a pipeline pressure sensor, a cabin temperature sensor, and a battery temperature sensor, which are electrically connected to the central control unit respectively.

[0011] As a further improvement of the present invention, the microchannel evaporation channel is made using a precision casting process or a metal 3D printing process.

[0012] As a further improvement of the present invention, the working fluid is an ethanol-water azeotropic mixture or graphene oxide nanofluid, with a filling rate of 45%-55%.

[0013] As a further improvement of the present invention, the ratio of the throat cross-sectional area to the inlet cross-sectional area of ​​the Venturi accelerator section is 1:2 to 1:4.

[0014] As a further improvement of the present invention, the proportional three-way flow regulating valve is configured to continuously adjust the ratio of coolant flow to the auxiliary heat dissipation branch and the waste heat utilization branch within the range of 0% to 100%.

[0015] This invention relates to an integrated thermal management method for aero-engines based on pulsating heat pipes at varying altitudes, comprising the following steps: Step S1: Global State Awareness Real-time data collection includes the aircraft's altitude H, airspeed Va, ambient temperature Tout, engine cylinder head temperature Tc, pulsating heat pipe internal pressure Pp, cockpit internal temperature Tin, and power battery temperature Tb. Step S2: Safety Pressure Monitoring Real-time monitoring of Pp; if Pp approaches the preset safety threshold PL, the intake regulating louvers are opened first and the electronic water pump and auxiliary heat dissipation branch are controlled to run at full speed for forced cooling and pressure reduction; if Pp exceeds PL, the pressure relief valve is triggered for physical pressure relief. Step S3: Multi-objective optimization control Based on the heat dissipation demand calculated using Tc, and the heating demand calculated using Tin and Tb, the following collaborative strategy is executed: (A) Ground idling and low-speed climb mode (low speed + high heat dissipation requirements): Control: The intake louvers are fully open; the auxiliary cooling circuit is activated to perform forced convection heat exchange to compensate for insufficient external ram air at low speeds; Liquid circuit control: The main flow is directed to the auxiliary radiator by the proportional three-way flow regulating valve, which uses active liquid cooling to quickly remove heat from the pulsating heat pipe and suppress knocking; Heating coordination: If there is a heating demand, activate the waste heat utilization branch and divert some of the coolant to the waste heat branch.

[0016] (B) High-altitude cruise mode (high speed + medium to low heat dissipation requirements): Airflow control: The auxiliary heat dissipation branch is closed to save power, and heat dissipation is carried out entirely by the ram acceleration effect of the Venturi air duct; the opening of the intake regulating louver and the exhaust regulating louver is adjusted in a timely manner according to the temperature. Hydraulic circuit control: Adjust the proportional three-way flow regulating valve to the "thermal balance position" to balance the flow rate of heat dissipation and waste heat recovery; Heating coordination: Activate the waste heat to maintain cabin circulation and maintain cabin and battery temperature.

[0017] (C) High-altitude dive / idle mode (high speed + extremely low heat production + strong heating demand): Airflow control: Close the auxiliary heat dissipation branch, and completely close or reduce the air intake regulating louvers to keep the temperature. Liquid circuit control: Adjust the proportional three-way flow regulating valve to the "full waste heat recovery position" to cut off the auxiliary heat dissipation branch; Heat source compensation: If the engine waste heat is insufficient, the air conditioning auxiliary heating module will be activated to work in conjunction with the waste heat utilization branch to achieve coordinated heating by waste heat utilization and air conditioning.

[0018] The beneficial effects of this invention are: 1. A cascaded architecture of "pulsating heat pipe (first-stage heat absorption) + active liquid cooling (second-stage heat transfer) + adaptive air duct (third-stage heat dissipation)" was constructed. Utilizing the equivalent thermal conductivity of the pulsating heat pipe, which is dozens of times higher than that of a copper rod of the same volume, the evaporation section is directly embedded into the heat accumulation area of ​​the cylinder block most prone to knocking. In the early stage of knocking, the working fluid phase change is used to quickly "absorb" local heat and homogenize it to the entire system, eliminating hot spots that may induce spontaneous combustion, thereby significantly improving the engine's anti-knock boundary.

[0019] 2. It overcomes the defect of heat dissipation being strongly coupled to flight speed in traditional solutions.

[0020] Liquid circuit decoupling: A proportional three-way flow regulating valve is used to continuously adjust the proportion of coolant flowing to the auxiliary heat dissipation branch and the waste heat utilization branch.

[0021] Decoupling of airflow: The system is equipped with an electronic cooling fan and a cabin blower.

[0022] (1) During low-altitude climbing (low speed and high load), although the external ram air is insufficient, the control system forces the electronic cooling fan to start, and with the fully open liquid circuit, it achieves strong suppression of the detonation temperature rise. (2) When cruising at high altitude (high speed and medium load), the electronic cooling fan is automatically shut down by utilizing high-speed ram air and the Venturi effect to achieve "zero power consumption cooling".

[0023] 3. A heating network of "waste heat utilization + air conditioning coordination" has been constructed; the waste heat utilization branch is connected in series with the cabin and the power battery insulation sleeve. When the waste heat is insufficient (such as in the diving condition), the air conditioning auxiliary heating module will automatically intervene; at the same time, an integrated pressure relief valve will physically release pressure when thermal runaway or external fire causes a surge in the pressure inside the pipe, to prevent secondary disasters. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the integrated thermal management system for aero-engine variable altitude based on a pulsed heat pipe according to the present invention. Figure 2 This is a schematic diagram of the microchannel evaporation flow channel distribution of the integrated thermal management system for variable altitude aero-piston engines based on pulsed heat pipes, as described in this invention. Explanation of reference numerals in the attached figures: 1. Engine body; 2. Pulsating heat pipe circulation cooling module; 21. Evaporator section; 22. Insulation section; 23. Condensation section; 24. Pressure relief valve; 3. Variable altitude air duct adjustment module; 31. Intake regulating louvers; 32. Venturi acceleration pipe section; 33. Exhaust regulating louvers; 4. Microchannel evaporator flow channel; 5. Multifunctional auxiliary active liquid cooling module; 51. Electronic water pump; 52. Liquid reservoir; 53. Auxiliary radiator; 531. Electronic cooling fan; 54. Coupled heat exchanger; 55. Proportional three-way flow regulating valve; 56. Cabin heating heat exchanger; 561. Cabin blower; 57. Air conditioning auxiliary heating module; 58. Power battery insulation sleeve; 6. Central control unit; 7. Altitude sensor; 8. Cylinder head temperature sensor; 9. Pipeline pressure sensor; 10. Cabin temperature sensor; 11. Battery temperature sensor. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the described embodiments are merely some, not all, of the embodiments of this invention. Unless otherwise specified, the embodiments and features described in this application can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0026] In one embodiment, see Figure 1 The present invention relates to an integrated thermal management system for aero-engines based on pulsating heat pipes with varying altitudes, comprising an engine body 1, a pulsating heat pipe circulating heat dissipation module 2, a varying altitude air duct adjustment module 3, a multi-functional auxiliary active liquid cooling module 5, and a central control unit 6.

[0027] Among them, a microchannel evaporation channel 4 is provided in the high heat load and easily detonated area inside the engine body 1; the pulsating heat pipe circulation heat dissipation module 2 is composed of multiple parallel capillary circuits connected end to end, the tubes are evacuated and filled with a gas-liquid two-phase working fluid, the capillary circuit includes an evaporation section 21 tightly embedded in the microchannel evaporation channel 4, an insulation section 22 connecting the heat source and the cold source, a condensation section 23 extending to the outside of the engine body, and a pressure relief valve 24 set on the high-pressure side of the capillary circuit; the variable altitude air duct adjustment module 3 is set on the windward side of the engine body, including a Venturi acceleration tube section 32, an intake adjustment louver 31 and an exhaust adjustment louver 33 arranged sequentially in the Venturi acceleration tube section 32 along the airflow direction; the condensation section 23 is placed horizontally at the throat of the Venturi acceleration tube section 32, using the airflow acceleration effect to enhance heat exchange; the multi-functional auxiliary active liquid cooling module 5 includes a liquid storage tank 52, an electronic water pump 51, a coupling heat exchanger 54, a proportional three-way flow regulating valve 55 connected in series, and auxiliary components arranged in parallel. The system includes a heat dissipation branch and a waste heat utilization branch; a coupling heat exchanger 54 is thermally coupled and wrapped around the outside of the insulation section 22; an auxiliary heat dissipation branch includes an auxiliary radiator 53 and its matching electronic cooling fan 531, used to dissipate heat to the external environment, and the electronic cooling fan 531 is configured to force air intake for heat dissipation under ground idling or low-speed high-load conditions; a waste heat utilization branch includes a cabin heating heat exchanger 56 and a power battery insulation jacket 58 arranged in series; the cabin heating heat exchanger 56 is equipped with a cabin blower 561, used to blow heat into the cabin; an air conditioning auxiliary heating module 57 is provided in the cabin heating air duct of the external fuselage, used to provide an active compensation heat source when the engine waste heat is insufficient; the central control unit 6 is electrically connected to the intake regulating louver 31, the exhaust regulating louver 33, the electronic water pump 51, the proportional three-way flow regulating valve 55, the auxiliary heat dissipation branch, the waste heat utilization branch and the air conditioning auxiliary heating module 57, and receives signals from various sensors to perform multi-target coupling control.

[0028] Various sensors include an altitude sensor 7, a cylinder head temperature sensor 8, a pipeline pressure sensor 9, a cabin temperature sensor 10, and a battery temperature sensor 11. The altitude sensor 7 is used to monitor the altitude of the engine body, the cylinder head temperature sensor 8 is used to monitor the temperature of the engine body 1, the pipeline pressure sensor 9 is used to monitor the internal pressure of the capillary tube, the cabin temperature sensor 10 is used to monitor the cabin temperature, and the battery temperature sensor 11 is used to monitor the temperature of the power battery.

[0029] See Figure 1 As shown, for the complex structure of the cylinder block, the microchannel evaporation channel 4 adopts a precision casting process or a metal 3D printing process to ensure that the evaporation section 21 fits seamlessly with the combustion chamber knock hotspots (cylinder liner upper edge, cylinder head bottom edge, exhaust valve accessories).

[0030] The diameter of the microchannel evaporation channel 4 strictly follows the Bond number criterion to ensure that the working fluid maintains plug flow or slug flow motion under variable gravity flight attitude and achieves overload resistance; the working fluid is preferably an ethanol-water azeotropic mixture or graphene oxide nanofluid, with a filling rate of 45%-55%.

[0031] The pressure relief valve 24 adopts a rupture disc or spring-loaded micro-opening structure. Its exhaust port is led to a safe area outside the machine body through a conduit. It is used to physically relieve pressure when the pressure inside the pipe exceeds the design threshold to prevent the pipe from bursting.

[0032] The Venturi accelerator section 32 is integrally formed from carbon fiber or glass fiber composite material, and the ratio of its throat cross-sectional area to its inlet cross-sectional area is 1:2 to 1:4.

[0033] The central control unit 6 is embedded with a multi-dimensional coupled control algorithm based on Bernoulli's principle and heat load requirements. It is used to calculate and adjust the optimal opening of the intake regulating louvers 31 based on the current altitude, outside air temperature, engine cylinder head temperature and cabin / battery heating requirements.

[0034] Cabin heating heat exchanger 56: Equipped with cabin blower 561, whose speed is determined by cabin temperature control requirements and is not affected by external airspeed.

[0035] The proportional three-way flow control valve 55 is the core of the system's fluid distribution. It is configured to continuously adjust the ratio of coolant flow to the auxiliary heat dissipation branch and the waste heat utilization branch within the range of 0% to 100%, and accurately distribute the coolant flow into the two branches according to the global thermal management strategy.

[0036] The central control unit 6 is configured to use "liquid-air coordination" control logic: adjust the opening of the proportional three-way flow regulating valve 55 according to the heat dissipation demand to control the flow rate, and at the same time adjust the start, stop and speed of the electronic cooling fan 531 according to the air speed and temperature to control the air volume, so as to achieve a smooth switch between active strong cooling and passive ram-press heat dissipation.

[0037] This system constructs a cascaded architecture of "pulsating heat pipe circulation heat dissipation (primary heat absorption) + multi-functional auxiliary active liquid cooling (secondary heat transfer) + fan-assisted adaptive air duct (tertiary heat dissipation)". Utilizing the pulsating heat pipe's equivalent thermal conductivity, which is 50-100 times higher than that of a copper rod of the same volume, this invention directly embeds the evaporation section 21 into the heat accumulation areas most prone to knocking in the cylinder block (upper edge of the cylinder liner, bottom edge of the cylinder head, and exhaust valve accessories). In the initial stage of knocking, the working fluid phase change rapidly "absorbs" local heat and homogenizes it throughout the entire system, eliminating hotspots that could induce spontaneous combustion, thereby significantly improving the engine's anti-knock boundary.

[0038] Dual decoupling control of fluid and air volume: This invention overcomes the shortcomings of traditional solutions where heat dissipation is strongly coupled to flight speed.

[0039] Liquid circuit decoupling: A proportional three-way flow regulating valve 55 is used to continuously adjust the proportion of coolant flowing to the auxiliary radiator 53 and the cabin heating heat exchanger 56.

[0040] Decoupling of airflow: The system is equipped with an electronic cooling fan 531 and a cabin blower 561.

[0041] (1) During low-altitude climbing (low speed and high load), although the external ram air is insufficient, the control system forces the electronic cooling fan 531 to be turned on, and with the fully open liquid circuit, it can strongly suppress the detonation temperature rise. (2) When cruising at high altitude (high speed and medium load), the electronic cooling fan 531 is automatically shut down by utilizing high-speed ram air and the Venturi effect to achieve "zero power consumption cooling".

[0042] Regarding heating and safety across the entire region: A heating network integrating waste heat utilization and air conditioning was constructed. The waste heat utilization branch connects the cabin and the power battery insulation sleeve 58 in series. When the waste heat is insufficient (such as in a dive operation), the air conditioning auxiliary heating module 57 automatically intervenes. At the same time, an integrated pressure relief valve 24 is used to physically release pressure in the pipes when thermal runaway or external fire causes a surge in pressure, preventing secondary disasters.

[0043] This invention relates to an integrated thermal management method for wide-range variable operating conditions of aero-engines based on pulsating heat pipes, comprising the following steps: Step S1: Global State Awareness Real-time data collection includes the aircraft's altitude H, airspeed Va, ambient temperature Tout, engine cylinder head temperature Tc, pulsating heat pipe internal pressure Pp, cockpit internal temperature Tin, and power battery temperature Tb. Step S2: Safety Pressure Monitoring Real-time monitoring of Pp; if Pp approaches the preset safety threshold PL, the intake regulating louver 31 is opened first and the electronic water pump 51 and electronic cooling fan 531 are controlled to run at full speed for forced cooling and pressure reduction; if Pp exceeds PL, the pressure relief valve 24 is triggered for physical pressure relief. Step S3: Multi-objective optimization control Based on the heat dissipation demand calculated using Tc, and the heating demand calculated using Tin and Tb, the following collaborative strategy is executed: (A) Ground idling and low-speed climb mode (low speed + high heat dissipation requirements): Control: The intake regulating louvers 31 are fully open; the electronic cooling fan 531 is activated to perform forced convection heat exchange to compensate for the problem of insufficient external ram air at low speeds; Liquid circuit control: The main flow of the regulating three-way flow regulating valve 55 is directed to the auxiliary radiator 53, and the active liquid cooling is used to quickly remove the heat from the pulsating heat pipe and suppress knocking. Heating cooperation: If there is a heating requirement, start the cabin blower 561 and divert part of the coolant to the waste heat branch.

[0044] (B) High-altitude cruise mode (high speed + medium-low heat dissipation requirement): Air duct control: Turn off the electronic radiator fan 531 to save electric energy, and rely entirely on the ram acceleration effect of the Venturi air duct for heat dissipation; adjust the louver opening in a timely manner according to the temperature; Liquid circuit control: Adjust the proportional three-way flow control valve 55 to the "thermal balance position" to balance the heat dissipation and waste heat recovery flow; Heating cooperation: Start the cabin blower 561 to maintain the cabin circulation, and use the waste heat to maintain the cabin and battery temperature.

[0045] (C) High-altitude dive / idle mode (high speed + extremely low heat generation + strong heating requirement): Air duct control: Turn off the electronic radiator fan 531, and completely close or reduce the intake air regulating louver 31 for heat preservation; Liquid circuit control: Adjust the proportional three-way flow control valve 55 to the "full waste heat recovery position" to cut off the auxiliary heat dissipation branch; Heat source compensation: If the engine waste heat is insufficient, start the air-conditioning auxiliary heating module 57 in cooperation with the cabin blower 561 to achieve coordinated heating of waste heat utilization and air conditioning.

[0046] The core of this system different from the traditional solution lies in "energy supply on demand" and "double decoupling".

[0047] Auxiliary radiator 53: Equipped with an electronic radiator fan 531; the central control unit 6 reads the data of the airspeed sensor; when Va < Vb (such as climbing or on the ground) and Tc is high, the fan runs at full speed for forced heat exchange; when Va > Vb (cruising), the fan stops running, and only relies on the ram air of the adaptive air duct for heat dissipation to reduce the system power consumption.

[0048] This system deeply integrates a closed-loop pulsed heat pipe network, a variable altitude adaptive air duct, and a multi-functional auxiliary liquid cooling circuit. Based on the combustion knock mechanism, a pulsed heat pipe evaporation section 21 is embedded in the cylinder block's knock-prone area. The ultra-high thermal conductivity of the working fluid during phase change instantly suppresses local high-temperature hotspots, effectively inhibiting knocking. The auxiliary liquid cooling circuit achieves on-demand continuous distribution of coolant between auxiliary heat dissipation and waste heat utilization through intelligent control of a proportional three-way flow regulating valve 55. The system adopts a dual-coupled control strategy of "liquid flow-air volume": the auxiliary radiator 53 and the cockpit heating heat exchanger 56 are respectively integrated with independently controlled electronic fans and blowers. The central control unit 6 dynamically adjusts the fan start / stop and speed according to flight speed and heat load. Combined with the ram effect of the Venturi air duct, it maximizes the reduction of cruise energy consumption while ensuring heat dissipation during takeoff / idle. In addition, the system integrates a pressure relief valve 24 and adopts a waste heat utilization and air conditioning coordinated heating strategy. When waste heat is insufficient, compensation is made through the air conditioning auxiliary heating module 57, achieving flight safety and precise temperature control under wide-range variable operating conditions.

[0049] Specific implementation examples under different typical operating conditions: Example 1: Summer ground takeoff and climb conditions (low speed + high load + high temperature) Operating parameters: ambient temperature Tout = 35℃, altitude H = 500m, airspeed Va = 150km / h, engine load 100%. Under these conditions, the tendency for knocking is extremely high.

[0050] Controlling actions: Airflow action: The central control unit 6 commands the intake regulating louver 31 and the exhaust regulating louver 33 to open to 100%; at the same time, it detects that the air speed is lower than the threshold and commands the electronic cooling fan 531 to run at 100% full speed to force convection heat exchange.

[0051] Hydraulic circuit operation: The proportional three-way flow regulating valve 55 adjusts the flow to 90% of the auxiliary radiator 53, and only 10% is reserved to flow to the waste heat branch to maintain the battery base temperature (if needed).

[0052] Effect: Through the rapid heat absorption of the pulsating heat pipe and the forced air cooling of the auxiliary radiator 53, the heat accumulated in the cylinder block is quickly removed, and the temperature of key parts is controlled below 110℃, successfully suppressing knocking.

[0053] Example 2: High-altitude economic cruise condition (high speed + medium load + low temperature) Operating parameters: ambient temperature Tout = -30℃, altitude H = 8000m, airspeed Va = 300km / h, engine load 65%.

[0054] Controlling actions: Airflow action: Upon detecting a high-speed ram airflow, the electronic cooling fan 531 is shut down to save power (achieving zero-power cooling). Based on the Bernoulli effect of the Venturi accelerator section 32, the opening of the intake regulating louver 31 is reduced to 30%, ensuring both heat dissipation and reducing flight drag.

[0055] Hydraulic circuit operation: Adjust the proportional three-way flow regulating valve 55 to the balanced position (e.g., 40% heat dissipation, 60% recovery).

[0056] Heating action: Start the cabin blower 561 to utilize waste heat recovery and transfer the recovered waste heat to the cabin and power battery to maintain the cabin temperature at 22°C and the battery temperature at 25°C.

[0057] Example 3: High-altitude long-distance dive / idling condition (high speed + extremely low heat generation + extreme cold) Operating parameters: Ambient air temperature Tout = -40℃, engine idling, generating very little heat, but the cabin and battery still need to be kept at a constant temperature.

[0058] Controlling actions: Airflow action: The intake regulating louver 31 is fully closed (0%), cutting off the external cold source and using the heat preservation effect to maintain the engine's base temperature and prevent sudden cooling.

[0059] Hydraulic circuit action: The proportional three-way flow regulating valve 55 is adjusted to the 100% waste heat recovery position to completely cut off the passage of the auxiliary radiator 53.

[0060] Coordinated heating action: Due to insufficient waste heat Q from the engine, the central control unit 6 automatically activates the air conditioning auxiliary heating module 57. At this time, waste heat utilization works in conjunction with the air conditioning system, combining the small amount of waste heat with electric heating.

[0061] Effect: Even with the engine generating almost no heat, the cabin and battery temperatures can still be maintained within a safe range of above 20°C.

[0062] Dual security mechanism Active safety: When an abnormal increase in the pulsating heat pipe pressure Pp is detected, the system enters emergency mode: the electronic cooling fan 531 runs at full speed, the louvers are fully open, the water pump circulates at full speed, and the proportional valve is fully opened to the heat dissipation side.

[0063] Passive safety: If the active measures fail and the pressure reaches the physical critical value, the pressure relief valve 24 will physically open to release the pressure and discharge the working fluid to the outside of the machine, fundamentally eliminating the risk of engine damage from pipeline rupture.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A pulse heat pipe based integrated variable altitude thermal management system for an aero-piston engine, characterized in that, include: The engine body (1) has a microchannel evaporation channel (4) in the high heat load and easily detonated area inside. The pulsed heat pipe circulation heat dissipation module (2) is composed of multiple parallel capillary tubes connected end to end. The tubes are evacuated and filled with a gas-liquid two-phase working fluid. The capillary tubes include an evaporation section (21) tightly embedded in the microchannel evaporation channel (4), an insulation section (22) connecting the heat source and the cold source, a condensation section (23) extending to the outside of the machine body, and a pressure relief valve (24) set on the high-pressure side of the capillary tubes. The variable altitude air duct adjustment module (3) is set on the windward side of the fuselage, including the Venturi acceleration tube section (32), the air intake adjustment louvers (31) and the exhaust adjustment louvers (33) arranged in sequence along the airflow direction in the Venturi acceleration tube section (32); the condensation section (23) is placed horizontally at the throat of the Venturi acceleration tube section (32) to enhance heat exchange by utilizing the airflow acceleration effect. The multi-functional auxiliary active liquid cooling module (5) includes a liquid storage tank (52), an electronic water pump (51), a coupling heat exchanger (54), a proportional three-way flow regulating valve (55) connected in series, and an auxiliary heat dissipation branch and a waste heat utilization branch connected in parallel; the coupling heat exchanger (54) is thermally coupled to the outside of the insulation section (22); the auxiliary heat dissipation branch is used to dissipate heat to the external environment; the waste heat utilization branch is used to blow heat into the cabin; the external fuselage is equipped with an air conditioning auxiliary heating module (57) in the cabin heating air duct, which is used to provide an active compensation heat source when the engine waste heat is insufficient; The central control unit (6) is electrically connected to the intake regulating louver (31), the exhaust regulating louver (33), the electronic water pump (51), the proportional three-way flow regulating valve (55), the auxiliary heat dissipation branch, the waste heat utilization branch and the air conditioning auxiliary heating module (57), and receives signals from various sensors to perform multi-target coupling control.

2. The pulsating heat pipe based aero-piston engine variable altitude integrated thermal management system of claim 1, wherein: The auxiliary heat dissipation branch includes an auxiliary heat sink (53) and its matching electronic cooling fan (531), which is configured to force airflow for heat dissipation under ground idling or low-speed high-load conditions.

3. The pulsating heat pipe based aero-piston engine variable altitude integrated thermal management system of claim 2, wherein: The waste heat utilization branch includes a cabin heating heat exchanger (56) and a power battery insulation sleeve (58) arranged in series; the cabin heating heat exchanger (56) is equipped with a cabin blower (561) for blowing heat into the cabin.

4. The pulsating heat pipe based aero-piston engine variable altitude integrated thermal management system of claim 3, wherein: It also includes an altitude sensor (7), a cylinder head temperature sensor (8), a pipeline pressure sensor (9), a cabin temperature sensor (10), and a battery temperature sensor (11), all of which are electrically connected to the central control unit (6).

5. The pulsating heat pipe based aero-piston engine variable altitude integrated thermal management system of claim 4, wherein: The microchannel evaporation channel (4) is manufactured using a precision casting process or a metal 3D printing process.

6. The pulsating heat pipe based aero-piston engine variable altitude integrated thermal management system of claim 5, wherein: The working fluid is an ethanol-water azeotropic mixture or graphene oxide nanofluid, with a filling rate of 45%-55%.

7. The pulsating heat pipe based aero-piston engine variable altitude integrated thermal management system of claim 6, wherein: The ratio of the throat cross-sectional area to the inlet cross-sectional area of ​​the Venturi accelerator section (32) is 1:2 to 1:

4.

8. The pulsating heat pipe based aero-piston engine variable altitude integrated thermal management system of claim 7, wherein: The proportional three-way flow regulating valve (55) is configured to continuously adjust the ratio of coolant flow to the auxiliary heat dissipation branch and the waste heat utilization branch within the range of 0% to 100%.

9. The integrated thermal management method for aero-engines based on pulsating heat pipes according to any one of claims 1-8, comprising the following steps: Step S1: Global State Awareness Real-time data collection includes the aircraft's altitude H, airspeed Va, ambient temperature Tout, engine cylinder head temperature Tc, pulsating heat pipe internal pressure Pp, cockpit internal temperature Tin, and power battery temperature Tb. Step S2: Safety Pressure Monitoring Real-time monitoring of Pp; if Pp approaches the preset safety threshold PL, the intake regulating louver (31) is opened first and the electronic water pump (51) and auxiliary heat dissipation branch are controlled to run at full speed for forced cooling and pressure reduction; If Pp exceeds PL, the pressure relief valve (24) is triggered to physically relieve pressure; Step S3: Multi-objective optimization control Based on the heat dissipation demand calculated using Tc, and the heating demand calculated using Tin and Tb, the following collaborative strategy is executed: (A) Ground idling and low-speed climb mode (low speed + high heat dissipation requirements): Control: The intake regulating louvers (31) are fully open; the auxiliary heat dissipation branch is activated to perform forced convection heat exchange to compensate for the problem of insufficient external ram air at low speed; Liquid circuit control: The main flow of the regulating three-way flow control valve (55) is directed to the auxiliary radiator (53), and the heat of the pulsating heat pipe is quickly removed by active liquid cooling to suppress knocking; Heating coordination: If there is a heating demand, activate the waste heat utilization branch and divert some of the coolant to the waste heat branch. (B) High-altitude cruise mode (high speed + medium to low heat dissipation requirements): Airflow control: Close the auxiliary heat dissipation branch to save power and rely entirely on the ram acceleration effect of the Venturi air duct for heat dissipation; adjust the opening of the intake regulating louver (31) and exhaust regulating louver (33) according to the temperature. Liquid circuit control: Adjust the proportional three-way flow regulating valve (55) to the "thermal balance position" to balance the flow of heat dissipation and waste heat recovery; Heating coordination: Activate the waste heat to maintain cabin circulation and maintain cabin and battery temperature. (C) High-altitude dive / idle mode (high speed + extremely low heat production + strong heating demand): Airflow control: Close the auxiliary heat dissipation branch, and completely close or reduce the intake regulating louvers (31) to keep warm; Liquid circuit control: Adjust the proportional three-way flow regulating valve (55) to the "full waste heat recovery position" to cut off the auxiliary heat dissipation branch; Heat source compensation: If the engine waste heat is insufficient, start the air conditioning auxiliary heating module (57) and cooperate with the waste heat utilization branch to realize the coordinated heating of waste heat utilization and air conditioning.

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