Thermal protection system and method for improving spreadability of sweating gas film on outer surface of aircraft

Abstract

The invention provides a thermal protection system and method for improving the spreadability of a sweating gas film on the outer surface of an aircraft. The thermal protection system comprises an upstream sweating area, a middle suction area, a downstream sweating area and a measurement control unit. The upstream sweating area is located at the front edge of a nose cone or a rudder wing of the aircraft, and the middle suction area and the downstream sweating area are communicated through a pipeline and are sequentially arranged on the surface of the aircraft at the downstream of the upstream sweating area in the flying airflow direction; the measurement control unit is used for measuring the heat flow of the sweating area and regulating and controlling the primary sweating of the upstream sweating area, the suction of the middle suction area and the secondary sweating of the downstream sweating area by controlling the states of the electronic pressure stabilizing valve, the electronic stop valve and the micro piezoelectric pump; the suction area is arranged at the sweating downstream, so that the spreadability of a sweating gas film is improved; and a re-sweating area is arranged at the downstream of the suction area, and the suction area and the re-sweating area are linked through a piezoelectric pump, so that recycling of cooling gas is realized.

Description

Technical Field

[0001] The invention relates to a thermal protection system and method for improving the spreading property of a sweat film on the outer surface of an aircraft, belonging to the technical field of aircraft heat reduction and drag reduction. Background Art

[0002] For high-speed cruising aircraft, the wave drag generated by the ubiquitous strong shock wave system accounts for two-thirds of the total cruise drag, and this proportion increases sharply with the increase of the incoming flow Mach number, which seriously affects the aerodynamic performance of the aircraft. At the same speed and range, more fuel needs to be consumed, which will greatly reduce the effective load. At the same time, the significant increase in flight speed enhances the viscosity between airflow molecules, and the heat flux on the wall of the aircraft head facing the incoming flow surges, causing the wall temperature to rise, which in turn damages the sensor device in the aircraft and causes a sharp drop in the working performance of the aircraft. These problems have made high-speed aircraft face severe challenges in practical applications. Therefore, it is imperative to develop new active heat reduction and drag reduction technologies. Transpiration cooling is a very potential active heat reduction and drag reduction technology. Its heat reduction and drag reduction are mainly manifested in two aspects: first, it utilizes the characteristics of high specific surface area of ​​porous media to absorb heat through convection; second, after the coolant flows out of the porous medium, it forms an air film on the surface to achieve heat reduction and drag reduction. High-speed aircraft often involve maneuvering flight (such as level flight acceleration / deceleration, dive and jump, etc.) during the execution of their missions. Under such highly dynamic flight conditions, when the sweating air film flows downstream along the surface of the aircraft, the flow state will become unstable, which will lead to poor spreading of the air film and affect the effect of reducing heat and drag. Summary of the invention

[0003] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, to provide a thermal protection system and method for improving the spread of the sweating air film on the outer surface of the aircraft, to enhance the sweating cooling, heat reduction and drag reduction effects, while being able to reduce the amount of working fluid used and improve the carrying efficiency of the aircraft.

[0004] The technical solution of the present invention is: on the one hand, a thermal protection system for improving the spreading property of the sweat film on the outer surface of an aircraft is provided, comprising: an upstream sweating area, an intermediate suction area, a downstream sweating area and a measurement control unit; wherein:

[0005] The upstream sweating area is located at the nose cone or the leading edge of the rudder wing of the aircraft and is used for initial sweating to form thermal protection for the upstream area;

[0006] The middle suction zone and the downstream sweating zone are connected by pipelines and arranged on the aircraft surface downstream of the upstream sweating zone in sequence along the airflow direction during flight; the middle suction zone performs suction to ensure the stable flow of the sweating air film; the downstream sweating zone is used for sweating again to form thermal protection for the downstream area;

[0007] The measurement control unit measures the heat flow of the upstream sweating zone, and regulates the initial sweating of the upstream sweating zone, the suction of the middle suction zone, and the re-sweating of the downstream sweating zone.

[0008] Preferably, the groove area provided at the leading edge of the aircraft nose cone or rudder wing in the upstream sweating zone includes a cold air bottle, a cold air cavity and a porous medium;

[0009] The cold air cavity is located at the lower part of the groove, the porous medium is located at the upper part of the groove, and the cold air bottle is connected to the cold air cavity.

[0010] Preferably, the intermediate suction zone and the downstream sweating zone have the same structure, both being groove areas arranged on the surface of the aircraft, including a porous medium located at the upper part of the groove and a cold air cavity at the lower part.

[0011] Preferably, the optimal distance from the upstream sweating zone to the middle suction zone and the optimal distance from the middle suction zone to the downstream sweating zone are determined by numerical simulation according to the incoming flow state and the characteristic size of the application area during the planning stage.

[0012] Preferably, the measurement control unit includes a data collector, a controller, a thermal flow sensor, an electronic pressure regulating valve, an electronic stop valve and a micro piezoelectric pump; specifically:

[0013] The heat flow sensor is embedded and packaged inside the porous medium in the upstream sweating zone;

[0014] The electronic pressure regulating valve is installed between the cold air bottle and the cold air cavity in the upstream sweating area;

[0015] The electronic shut-off valve and the micro piezoelectric pump are installed on the pipeline between the middle suction zone and the downstream sweating zone.

[0016] Preferably, the number of intermediate suction zones and downstream sweat zones is determined according to specific usage conditions.

[0017] On the other hand, a thermal protection method for improving the spreading property of a sweat film on the outer surface of an aircraft is provided, comprising:

[0018] During the flight of the aircraft, the data collector obtains the measurement values ​​of the heat flow sensor in real time and sends them to the controller;

[0019] When the actual heat flux value measured by the heat flux sensor is greater than the design value, the controller switches the electronic pressure regulating valve from the closed state to the open state, so that the cooling gas flows from the cold air bottle along the pipeline into the cold air cavity and the porous medium of the upstream sweating zone in sequence, and flows out of the aircraft surface after completing the heat exchange;

[0020] The controller converts the electronic shut-off valve from a closed state to an open state, and controls the operation of the micro piezoelectric pump, so that the cooling gas flowing out of the surface of the aircraft flows downstream along the surface of the aircraft under the combined action of the positive pressure of the incoming gas and the negative pressure of the intermediate suction zone. When flowing to the intermediate suction zone, part of the cooling gas continues to flow downstream, and the other part of the gas enters the porous medium and cold air cavity of the intermediate suction zone under the action of the micro piezoelectric pump, and then reaches the cold air cavity and porous medium of the downstream sweating zone through the pipeline, and finally flows out of the surface of the aircraft again and continues to flow downstream, thereby improving the spreadability of the sweating air film.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] (1) Based on the sweating cooling, the present invention proposes the idea of ​​arranging a suction area downstream, which solves the problem of poor spreading of the sweating cooling air film during high-maneuver flight and can effectively improve the effect of sweating to reduce heat and drag;

[0023] (2) The present invention arranges a re-sweating zone downstream of the suction zone, and the suction zone and the re-sweating zone are linked by a micro piezoelectric pump, thereby realizing the reuse of the cooling gas. While improving the sweating, heat reduction and drag reduction effects, it can reduce the amount of working fluid used and improve the carrying efficiency of the aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the system composition of the present invention;

[0025] Figure 2 The figure is a flow chart of the working method of the system of the present invention. DETAILED DESCRIPTION

[0026] The upstream sweating area 1 is located at the nose cone or the leading edge of the rudder wing of the aircraft and is used for initial sweating to form thermal protection for the upstream area;

[0027] The intermediate suction area 2 and the downstream sweating area 3 are connected by a pipeline 6, and are arranged in sequence on the aircraft surface downstream of the upstream sweating area 1 along the airflow direction in flight; the intermediate suction area 2 is used for suction to ensure the flow stability of the sweating air film; the downstream sweating area 3 is used for sweating again to form thermal protection for the downstream area;

[0028] The measurement control unit 4 is used to measure the heat flow in the sweating zone, and regulate the initial sweating in the upstream sweating zone, the suction in the middle suction zone and the re-sweating in the downstream sweating zone by controlling the states of the electronic pressure regulating valve, the electronic stop valve and the micro piezoelectric pump.

[0029] The cold air cavity 12 is located at the lower part of the groove, the porous medium 13 is located at the upper part of the groove, and the cold air bottle 11 is connected to the cold air cavity 12; the intermediate suction area 2 and the downstream sweating area 3 have the same structure, both of which are groove areas set on the surface of the aircraft, including the porous medium located at the upper part of the groove and the cold air cavity at the lower part.

[0030] like Figure 1 As shown, the thermal protection system for improving the spreadability of the sweat film on the outer surface of an aircraft of the present invention comprises an upstream sweating area 1, an intermediate suction area 2, a downstream sweating area 3 and a measurement control unit 4; the upstream sweating area 1, the intermediate suction area 2 and the downstream sweating area 3 are arranged on the aircraft surface 5; the aircraft surface 5 is particularly suitable for the nose cone or the leading edge of the rudder wing of the aircraft; the upstream sweating area 1 comprises a cold air bottle 11, a cold air cavity 12 and a porous medium 13; the intermediate suction area 2 comprises a porous medium 21 and a cold air cavity 22; the downstream sweating area 3 comprises a porous medium 31 and a cold air cavity 32 The intermediate suction zone 2 and the downstream sweating zone 3 are connected through a pipeline 6; the measurement control unit 4 includes a data acquisition device 41, a controller 42, a heat flow sensor 43, an electronic pressure regulating valve 44, an electronic stop valve 45 and a micro piezoelectric pump 46; the heat flow sensor 43 is embedded and packaged inside the porous medium 13 of the upstream sweating zone 1; the electronic pressure regulating valve 44 is installed between the cold air bottle 11 and the cold air cavity 12 of the upstream sweating zone 1; the electronic stop valve 45 and the micro piezoelectric pump 46 are installed on the pipeline 6 between the intermediate suction zone 2 and the downstream sweating zone 3. The number of the intermediate suction zone 2 and the downstream sweating zone 3 is not limited to one, and can be flexibly determined according to the specific usage.

[0031] like Figure 1 and Figure 2 As shown, the working process of the present invention is as follows: during the flight of the aircraft, the data acquisition device 41 obtains the measurement value of the heat flow sensor 43 in real time and transmits it to the controller 42; when the actual heat flow value measured by the heat flow sensor 43 is greater than the design value, the controller 42 converts the electronic pressure regulating valve 44 and the electronic stop valve 45 from the closed state to the open state, and controls the micro piezoelectric pump 46 to work; under the action of pressure, the cooling gas enters the cold air cavity 12 and the porous medium 13 along the pipeline from the cold air bottle 11 in turn, and flows out after completing the heat exchange. The cooling gas flowing out of the aircraft surface 5 flows downstream along the aircraft surface 5 under the combined effect of the positive pressure of the incoming gas and the negative pressure of the intermediate suction zone 2. When it flows to the intermediate suction zone 2, a part of the cooling gas continues to flow downstream, and the other part of the gas enters the porous medium 21, the cold air cavity 22, the pipeline 6, the cold air cavity 32 and the porous medium 31 of the downstream sweating zone 3 in sequence under the action of the micro piezoelectric pump 46, and finally flows out of the aircraft surface 5 again and continues to flow downstream.

[0032] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in this field.

Claims

1. A thermal protection system for improving the spreading property of the sweat film on the outer surface of an aircraft, characterized in that include: An upstream sweating zone (1), an intermediate suction zone (2), a downstream sweating zone (3) and a measurement control unit (4); wherein: The upstream sweating area (1) is located at the nose cone or the leading edge of the rudder wing of the aircraft and is used for initial sweating to form thermal protection for the upstream area; The intermediate suction area (2) and the downstream sweating area (3) are connected through a pipeline (6) and are arranged in sequence on the aircraft surface downstream of the upstream sweating area (1) along the airflow direction during flight; the intermediate suction area (2) performs suction to ensure stable flow of the sweating air film; the downstream sweating area (3) is used for sweating again to form thermal protection for the downstream area; The measurement control unit (4) measures the heat flow of the upstream sweating zone, and regulates the initial sweating of the upstream sweating zone, the suction of the middle suction zone, and the re-sweating of the downstream sweating zone.

2. A thermal protection system for improving the spreading property of the sweat film on the outer surface of an aircraft according to claim 1, characterized in that: The upstream sweating area (1) is a groove area provided on the nose cone or the leading edge of the rudder wing of the aircraft, including a cold air bottle (11), a cold air cavity (12) and a porous medium (13); The cold air cavity (12) is located at the lower part of the groove, the porous medium (13) is located at the upper part of the groove, and the cold air bottle (11) is connected to the cold air cavity (12).

3. A thermal protection system for improving the spreading property of the sweat film on the outer surface of an aircraft according to claim 2, characterized in that: The structures of the intermediate suction area (2) and the downstream sweating area (3) are the same, both of which are groove areas arranged on the surface of the aircraft, including a porous medium located at the upper part of the groove and a cold air cavity at the lower part.

4. A thermal protection system for improving the spreading property of the sweat film on the outer surface of an aircraft according to claim 1, characterized in that: The optimal distance between the upstream sweating zone (1) and the middle suction zone (2) and the optimal distance between the middle suction zone (2) and the downstream sweating zone (3) are determined by numerical simulation according to the incoming flow state and the characteristic size of the application area during the planning stage.

5. A thermal protection system for improving the spreading property of the sweat film on the outer surface of an aircraft according to claim 3, characterized in that: The measurement control unit (4) comprises a data acquisition device (41), a controller (42), a thermal flow sensor (43), an electronic pressure regulating valve (44), an electronic stop valve (45) and a micro piezoelectric pump (46); specifically: The heat flow sensor (43) is embedded and packaged inside the porous medium (13) of the upstream sweating area (1); The electronic pressure regulating valve (44) is installed between the cold air bottle (11) and the cold air cavity (12) in the upstream sweating zone (1); The electronic stop valve (45) and the micro piezoelectric pump (6) are installed on the pipeline (6) between the middle suction area (2) and the downstream sweating area (3).

6. A thermal protection system for improving the spreading property of the sweat film on the outer surface of an aircraft according to claim 1, characterized in that: The number of the intermediate suction zone (2) and the downstream sweating zone (3) is determined according to the specific usage.

7. A thermal protection method for improving the spreading property of the sweat film on the outer surface of an aircraft, characterized in that include: During the flight of the aircraft, the data collector (41) acquires the measurement value of the heat flow sensor (43) in real time and sends it to the controller (42); When the actual heat flow value measured by the heat flow sensor (43) is greater than the design value, the controller (42) switches the electronic pressure regulating valve (44) from a closed state to an open state, so that the cooling gas flows from the cold air bottle (11) along the pipeline into the cold air cavity (12) and the porous medium (13) of the upstream sweating area (1) in sequence, and flows out of the aircraft surface after completing the heat exchange; The controller (42) converts the electronic shut-off valve (45) from a closed state to an open state, and controls the operation of the micro piezoelectric pump (46), so that the cooling gas flowing out of the aircraft surface flows downstream along the aircraft surface under the combined action of the positive pressure of the incoming gas and the negative pressure of the intermediate suction zone (2). When flowing to the intermediate suction zone (2), a part of the cooling gas continues to flow downstream, and the other part of the gas enters the porous medium and cold air cavity of the intermediate suction zone (2) under the action of the micro piezoelectric pump (46), and then reaches the cold air cavity and porous medium of the downstream sweating zone (3) through the pipeline (6), and finally flows out of the aircraft surface again and continues to flow downstream, thereby improving the spreading property of the sweating air film.

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