Aircraft air inlet lip and cooling and heat insulation method

Abstract

The present invention discloses an aircraft air inlet lip and a method for cooling and insulating the air inlet lip. The air inlet lip is mainly composed of a mounting plate, an inlet pipe, a lip structure, a lip front end, and an outlet pipe. The leading edge of the aircraft air inlet lip forms a high-temperature surface due to aerodynamic heating. Aircraft fuel is used as a cooling medium and flows into the upper and lower independent flow channels in the heat dissipation core through the inlet pipe, exchanges heat with the lip structure, and finally flows out through the outlet pipe, taking away the heat, so that the temperature of the lip structure is reduced to within the temperature range allowed by the material. The present invention reduces the temperature of the lip structure by adopting a functional integration design concept. The lip heat insulation and cooling structure, form, and flow channel layout of the present invention are reasonable. Aircraft fuel is used as a cooling medium to actively reduce the temperature of the lip structure and improve the surface temperature distribution of the lip structure.

Description

Technical Field

[0001] The invention relates to an aircraft air inlet lip and a temperature reduction and heat insulation method, belonging to the field of cold plate radiator design. Background Art

[0002] During flight, aerodynamic heating of the airframe surface can cause surface temperatures in areas such as the leading edge of the inlet lip to reach over 600°C, often for extended periods. The lip is a thin, sharp structure with a low profile, resulting in a small design envelope and significant design challenges. Currently, a common approach is to add high-temperature ceramics or spray high-temperature-resistant coatings onto the surface. When the aircraft's flight speed is relatively low (less than 4 Ma), the airflow temperature rise is not significant, and the use of high-temperature-resistant materials or spraying of high-temperature-resistant coatings can meet these requirements. However, as the aircraft's flight speed continues to increase, the airflow temperature rise increases significantly, and these aforementioned methods are unable to effectively address the problem of elevated temperatures at the lip-to-airframe connection.

[0003] As another approach, the Chinese patent "Active Cooling System for Spaceplanes Based on Magnetic Fluid Energy Bypass" (CN110318878A, October 11, 2019) uses alkali metal high-temperature heat pipes to actively cool high-temperature areas such as the leading edge and lip of the aircraft's inlet. When the flight speed exceeds 8 Ma, the control valve on the supersonic inlet active cooling high-temperature heat pipe is opened, and fuel containing alkali metals is injected into the inlet. However, this implementation is relatively complex and costly. Summary of the Invention

[0004] The present invention aims to provide an aircraft air inlet lip and a cooling and heat insulation method. This method replaces traditional cooling and heat insulation methods such as coatings or paints, adopts a functionally integrated design, combines the lip structure with a cold plate radiator, and uses the fuel on the aircraft as a cooling medium to cool the lip structure, remove heat, and bring the lip structure temperature within the temperature range allowed by the material, thereby solving the problem of high temperature at the connection between the lip structure and the fuselage.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] An aircraft air inlet lip, wherein the lip edge of the lip is a pointed and thin structure, and the end of the lip away from the lip edge is connected to the aircraft body, and the lip includes:

[0007] a lip structure, wherein the lip structure is a hollow structure, a heat dissipation core is disposed in the hollow structure, and a first end of the lip structure is connected to the aircraft body;

[0008] The front end of the lip is a solid, pointed, and thin structure, and the front end of the lip is connected to the second end of the lip structure, and the front end of the lip is not connected to the heat dissipation core;

[0009] A cooling medium flows in the heat dissipation core, and the cooling medium is fuel carried by the aircraft itself.

[0010] Furthermore, the aircraft air inlet lip also includes,

[0011] an inlet pipe connected to the first side of the lip structure;

[0012] an outlet pipe connected to the second side of the lip structure;

[0013] The first side surface and the second side surface are two opposite surfaces on the lip structure, and the cooling medium flows into the heat dissipation core in the lip structure through the inlet pipe and flows out of the heat dissipation core through the outlet pipe.

[0014] Furthermore, the aircraft air inlet lip also includes two mounting plates.

[0015] One of the mounting plates is connected to the inlet end of the inlet pipe, which is a circular pipe with a constant cross-section;

[0016] The other mounting plate is connected to the outlet end of the outlet pipe, and the outlet pipe is a circular pipe with a constant cross-section.

[0017] Furthermore, the heat dissipation core includes a plurality of independent flow channels, the inlet ends of the flow channels are connected to the inlet pipe, and the outlet ends of the flow channels are connected to the outlet pipe.

[0018] Furthermore, the heat dissipation core includes an upper layer flow channel and a lower layer flow channel connected in parallel with each other, wherein the inlet of the upper layer flow channel is connected to the inlet of the lower layer flow channel, the outlet of the upper layer flow channel is connected to the outlet of the lower layer flow channel, the upper layer flow channel is close to the upper surface of the lip structure, and the lower layer flow channel is close to the lower surface of the lip structure.

[0019] Furthermore, both the upper and lower flow channels are ribbed, and each contains four flows. Currently, heat dissipation structures are mainly divided into ribbed, plate-fin, and tube-in-tube types. The ribbed type is used here, in which the flow channels are formed on the substrate through machining, which can be referred to as the structure of a harmonica pipe.

[0020] Furthermore, the ribs of the upper and lower flow channels are provided with holes, and the holes are located close to the same side of the upper and lower wing surfaces.

[0021] Furthermore, there is an arc-shaped transition between the flow channels of adjacent processes in the upper flow channel and the lower flow channel.

[0022] As an option, the mounting plate, inlet pipe, outlet pipe and lip structure are integrally formed by 3D printing and are finally connected to the front end of the lip by welding.

[0023] A method for cooling and insulating an aircraft air inlet lip comprises: providing a heat exchange structure within the lip, and splitting the lip into a first portion with the heat exchange structure and a second portion without the heat exchange structure. The first portion is connected to the fuselage, and the second portion serves as the lip edge. The medium flowing in the heat exchange structure is fuel carried by the aircraft itself. The first portion is cooled through fuel heat exchange. Both the first and second portions are made of high-temperature resistant materials, and the second portion has better high-temperature resistance than the first portion.

[0024] In the present invention, the cooling medium flows into the heat dissipation core in the lip structure through the inlet pipe. When the heat dissipation core includes a flow channel, the cooling medium undergoes heat exchange through the flow channel of the heat dissipation core and flows out from the outlet pipe, taking away heat and ultimately reducing the temperature of the lip structure.

[0025] The present invention utilizes the fuel carried by the aircraft itself as a cooling medium to reduce the temperature of the lip structure so that the temperature of the lip structure reaches the temperature range allowed by the material. The lip structure becomes a heat insulating structure between the front end of the lip and the fuselage.

[0026] The design of the flow channel in the heat dissipation core of the present invention has been carefully calculated and verified. By controlling the inlet temperature and flow rate of the cooling medium, the temperature of the lip structure can be effectively reduced, the temperature distribution is uniform, and the temperature of the lip structure reaches the temperature range allowed by the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the aircraft air inlet lip structure of the present invention;

[0028] Figure 2 for Figure 1 Right view;

[0029] Figure 3 This is a schematic diagram of the structure of the mounting plate, inlet pipe, lip structure, and outlet pipe of the present invention formed in one piece by 3D printing;

[0030] Figure 4 for Figure 3 Top view and AA and BB cross-sectional views;

[0031] Figure 5 Schematic diagram of the ribbed plate flow channel (4 processes) in the heat dissipation core of the present invention;

[0032] Figure 6 This is a schematic diagram of the front end structure of the lip of the present invention;

[0033] In the figure: 1 - mounting plate, 2 - inlet pipe, 3 - outlet pipe, 4 - lip structure, 5 - front end of lip, 6 - small hole, 7 - groove. DETAILED DESCRIPTION

[0034] The present invention is further described below with reference to the accompanying drawings and specific embodiments. However, it should not be understood that the scope of the subject matter described in the present invention is limited to the following embodiments. Without departing from the above technical ideas of the present invention, various modifications, substitutions and changes made according to common technical knowledge and customary means in the field are included in the scope of the present invention.

[0035] like Figures 1 to 6 As shown, in this embodiment, the aircraft inlet lip comprises a mounting plate 1, an inlet duct 2, an outlet duct 3, a lip structure 4, and a lip front end 5. The mounting plate 1, inlet duct 2, outlet duct 3, and lip structure 4 are integrally formed via 3D printing and then welded to the solid, thin, pointed lip front end 5 to form the lip. The aircraft inlet lip is connected to the aircraft fuselage via a groove 7.

[0036] like Figure 3 As shown, the mounting plate 1, the inlet pipe 2, the outlet pipe 3 and the lip structure 4 are integrally formed by 3D printing;

[0037] like Figure 6 As shown, the solid, pointed and thin lip front end 5 is connected to the lip structure 4 by welding;

[0038] like Figure 4 、 Figure 5 As shown, the internal structure of the heat dissipation core formed by 3D printing, the flow channel is arranged in two layers in parallel, with four processes in each layer. The upper flow channel is close to the upper surface of the lip structure 4, and the lower flow channel is close to the lower surface of the lip structure 4. Both the upper and lower flow channels are plate-rib structures. Figure 5 A "W"-shaped flow channel is drawn in the figure, forming four processes. Adjacent processes are connected by arc-shaped flow channels when turning. Figure 5 The central rib plate structure includes a rib structure along the flow direction of the cooling medium ("W" shape), and a rib structure extending horizontally and vertically ( Figure 5 There are 3 horizontal and 3 vertical rib structures in the structure), and the 3 horizontal rib structures are all provided with small holes 6, which can be referred to Figure 4 Small holes 6 are provided on the transverse ribs of the upper and lower flow channels, and are located close to the same side of the upper and lower airfoils, i.e., either uniformly close to the upper or lower airfoil. These holes 6 are used for the flow of cooling fluid, and their proximity to the same side facilitates cleaning of internal support materials after integral molding (e.g., 3D printing).

[0039] like Figure 1As shown, the lip structure 4 and the lip front end 5 are connected by welding, and the temperature distribution of the lip shows a trend of gradually decreasing from the lip front end 5 to the lip structure 4. The material of the lip structure 4 is TC4 titanium alloy, and the material of the lip front end 5 is Ti60 titanium alloy which is more resistant to high temperatures.

[0040] like Figure 3 As shown, the mounting plate 1 is two flange-shaped flat plates with a circular hole in the middle. The lip structure 4, the inlet pipe 2, the outlet pipe 3 and the mounting plate 1 are integrally formed by 3D printing. The aircraft air inlet lip is installed on the aircraft through the groove 7.

[0041] like Figure 4 and Figure 5 As shown, the aircraft's fuel, acting as a coolant, flows through the heat dissipation core within the lip structure 4 via the inlet pipe 2. During this flow, the coolant comes into contact with the lip structure 4 over a large area, exchanging heat, removing heat from the lip structure 4 and exiting through the outlet pipe 3. The heat dissipation core is divided into upper and lower flow channels. Each channel consists of multiple independent flow paths, each with four parallel, linear channels, with adjacent channels flowing in opposite directions. Arc-shaped transitions between adjacent channels facilitate the flow of the coolant. The channels utilize an upper and lower parallel structure (i.e., the inlet of the upper channel connects to the inlet of the lower channel, and the outlet of the upper channel connects to the outlet of the lower channel). This maximizes the contact area between the coolant and the lip structure 4, improving heat exchange efficiency. The channel design is ribbed, ensuring sufficient strength and rigidity for the heat dissipation core and lip structure 4.

[0042] like Figure 6 As shown, the front end 5 of the lip is a thin plate with an airfoil curvature (pointed and thin structure). In order to withstand high temperatures, it is made of Ti60 titanium alloy and is connected to the lip structure 4 by welding.

[0043] The above embodiments are not intended to limit the protection scope of the present invention. Any variations, modifications or equivalent substitutions made on the basis of the technical solution of the present invention shall fall within the protection scope of the present invention.

Claims

1. An aircraft air inlet lip, wherein the lip edge is a pointed and thin structure, and the end of the lip away from the lip edge is connected to the aircraft body, characterized in that: Lips include, A lip structure (4), wherein the lip structure (4) is a hollow structure, a heat dissipation core is provided in the hollow structure, and a first end of the lip structure (4) is connected to the aircraft body; A lip front end (5), wherein the lip front end (5) is a solid, pointed, and thin structure, and the lip front end (5) is connected to the second end of the lip structure (4), and the lip front end (5) is not connected to the heat dissipation core; A cooling medium flows in the heat dissipation core, and the cooling medium is fuel carried by the aircraft itself; an inlet pipe (2), the inlet pipe (2) being connected to a first side surface of the lip structure (4); an outlet pipe (3), the outlet pipe (3) being connected to a second side surface of the lip structure (4); The first side surface and the second side surface are two opposite surfaces on the lip structure (4), and the cooling medium flows into the heat dissipation core in the lip structure (4) through the inlet pipe (2) and flows out of the heat dissipation core through the outlet pipe (3); The heat dissipation core comprises an upper flow channel and a lower flow channel connected in parallel to each other, wherein the inlet of the upper flow channel is connected to the inlet of the lower flow channel, the outlet of the upper flow channel is connected to the outlet of the lower flow channel, the upper flow channel is closely attached to the upper surface of the lip structure (4), and the lower flow channel is closely attached to the lower surface of the lip structure (4); Also included are two mounting plates (1), One of the mounting plates (1) is connected to the inlet end of the inlet pipe (2), and the inlet pipe (2) is a circular pipe with a uniform cross-section; Another mounting plate (1) is connected to the outlet end of the outlet pipe (3), and the outlet pipe (3) is a circular pipe with a constant cross-section.

2. The aircraft air inlet lip according to claim 1, characterized in that: The heat dissipation core comprises a plurality of independent flow channels, the inlet ends of the flow channels are connected to the inlet pipe (2), and the outlet ends of the flow channels are connected to the outlet pipe (3).

3. The aircraft air inlet lip according to claim 1, characterized in that: The upper flow channel and the lower flow channel are both ribbed type, and each of the upper flow channel and the lower flow channel includes four processes.

4. The aircraft air inlet lip according to claim 3, characterized in that: The ribs of the upper and lower flow channels are provided with openings, and the openings are located close to the same side of the upper and lower wing surfaces.

5. The aircraft air inlet lip according to claim 1, characterized in that: There is an arc-shaped transition between the flow channels of adjacent processes in the upper flow channel and the lower flow channel.

6. The aircraft air inlet lip according to claim 1, characterized in that: The mounting plate (1), the inlet pipe (2), the outlet pipe (3) and the lip structure (4) are integrally formed by 3D printing and are finally welded to the front end of the lip (5).

7. The method for cooling and insulating an aircraft air inlet lip according to any one of claims 1 to 6, characterized in that: A heat exchange structure is set in the lip, and the lip is divided into a first part with a heat exchange structure and a second part without a heat exchange structure. The first part is connected to the fuselage, and the second part serves as the lip edge. The medium flowing in the heat exchange structure is the fuel carried by the aircraft itself. The first part is cooled by fuel heat exchange. Both the first and second parts are made of high-temperature resistant materials, and the high-temperature resistance of the second part is better than that of the first part.

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