Surface treatment optimization method suitable for aircraft cooling

Abstract

The invention provides a surface treatment optimization method suitable for cooling of an aircraft, and the surface roughness of the aircraft is changed by adopting an ultrasonic-assisted laser polishing mode so as to change the heat flow distribution of the surface of the aircraft; wherein the surface roughness of the aircraft is nanoscale. According to the method, the surface roughness of the aircraft is changed in an ultrasonic-assisted laser polishing mode, the surface heat flow is reduced under the condition that the structure of the high-speed aircraft is not changed, the technological operation is simple and feasible, and the risk is controllable.

Description

Technical Field

[0001] This invention belongs to the field of aircraft surface heat reduction optimization design technology, specifically, it relates to a surface treatment optimization method suitable for aircraft heat reduction. In particular, it relates to a surface ultrasonic-assisted laser polishing method suitable for heat reduction of high-speed aircraft. Background Technology

[0002] High-speed aircraft experience intense friction with the surrounding air during flight, generating enormous aerodynamic heat that severely impacts their flight performance. Therefore, reducing the aerodynamic heat hazards of high-speed aircraft is a crucial aspect that must be considered during their development.

[0003] On the one hand, conservatively designed thermal protection structures can reduce aerodynamic heat hazards, such as by thickening coatings and adding insulation layers. However, this also increases the weight of the thermal protection structure, resulting in a higher proportion of negative mass. On the other hand, changing the aircraft's shape can reduce surface heat flux; for example, a blunt conical structure has lower heat flux than a pointed conical structure, but this also reduces the aircraft's aerodynamic capabilities. Currently, the design of heat reduction structures for high-speed aircraft, both domestically and internationally, typically involves altering the aircraft's surface structure or controlling the flow field, such as by introducing wedge-shaped structures or controlling shock waves.

[0004] Patent document CN117326045A reduces heat transfer by introducing a wedge-shaped structure to alter the flow field near the wall and decrease shock wave interference. Patent document CN106184743A uses a high-pressure gas source jet device or a plasma synthesis jet device to control the shock wave flow field and reduce heat flux in critical areas. Patent document CN115384759A reduces boundary layer heat flux by generating an air film on the aircraft surface.

[0005] The aforementioned patent documents mostly introduce additional structures on the surface of aircraft to achieve heat reduction, and most of these methods have not been experimentally verified, so the potential risks they pose are still unknown. Currently, there are no reports in the existing technology regarding surface treatment of aircraft for heat reduction.

[0006] To address the shortcomings of existing technologies, this invention employs ultrasonic-assisted laser polishing surface treatment to achieve heat reduction in high-speed aircraft without altering the aircraft's surface structure.

[0007] Patent document CN119115669A provides a nano-smooth surface treatment method and system suitable for aircraft drag reduction, including: sandblasting the operation area of ​​the surface; dividing the operation area into strips; determining the scanning path according to the strips; determining the laser power, scanning rate and defocusing amount according to the strips and target roughness, and formulating a laser strategy; polishing according to the laser strategy; and cleaning the polished surface.

[0008] Patent document CN119115669A aims to reduce drag in aircraft, specifically for drag reduction during flight at no angle of attack. This invention, however, aims to reduce heat in aircraft at high angles of attack, i.e., reducing heat flux on the aircraft surface. The former focuses on drag reduction at no angle of attack, while the latter focuses on heat reduction at high angles of attack. Therefore, given their different objectives, the optimal polishing strip selection differs. The former uses an intermittent polishing strip strategy, while the latter uses a continuous arrangement on the rear half of the surface, avoiding an intermittent distribution. Furthermore, the laser polishing strategy used in patent document CN119115669A suffers from excessive spatter, a large heat-affected zone, excessive particle aggregation and deposition, and excessive material vapor condensation during actual operation, resulting in numerous and difficult cleaning steps after completion. To address this, this invention introduces an ultrasonic-assisted laser polishing strategy, which significantly reduces spatter, condensation, and deposits during processing, and facilitates cleaning after completion. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the purpose of this invention is to provide an optimized surface treatment method suitable for aircraft heat reduction.

[0010] According to the present invention, a surface treatment optimization method for aircraft heat reduction is provided, which uses ultrasonic-assisted laser polishing to change the surface roughness of the aircraft, thereby changing the heat flow distribution on the aircraft surface.

[0011] The surface roughness of the aircraft is at the nanometer level.

[0012] Preferably, ultrasonic-assisted laser polishing is used for the surface treatment of the nose cone, wings, leading edges of the control surfaces, fuselage, and flat areas of the aircraft.

[0013] Preferably, the surface of the aircraft is polished using a semi-surface polishing process to form polished strips and non-polished strips.

[0014] Preferably, the polishing strips are arranged continuously on the rear surface of the aircraft, avoiding an intermittent distribution.

[0015] Preferably, all polishing strips are arranged on the rear surface of the aircraft.

[0016] Preferably, the polishing strips are arranged on the rear surface of the aircraft.

[0017] Preferably, the polishing strips are mostly arranged on the rear surface of the aircraft.

[0018] Preferably, it includes:

[0019] Step S1: Surface sandblasting to remove oil and dirt;

[0020] Step S2: Divide the polishing strips;

[0021] Step S3: Determine the laser scanning path, laser power, scanning speed, defocusing amount, and ultrasonic frequency;

[0022] Step S4: Continuous laser polishing;

[0023] Step S5: Surface cleaning;

[0024] Step S6: Check if the surface roughness reaches the nanometer level; if yes, end the process; if no, proceed to step S3 to continue execution.

[0025] According to the present invention, the surface of an aircraft is processed by the aforementioned surface treatment optimization method suitable for aircraft heat reduction.

[0026] An aircraft according to the present invention is characterized by comprising the surface of the aircraft.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] This invention changes the surface roughness of an aircraft through ultrasonic-assisted laser polishing, solving the problem of reducing surface heat flux in high-speed aircraft without altering their structure. The process is simple, feasible, and the risks are controllable. Attached Figure Description

[0029] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0030] Figure 1 This is a schematic diagram illustrating the working principle of the present invention.

[0031] Figure 2 This is a schematic diagram of the surface heat flux coefficient distribution.

[0032] Figure 3 This is another schematic diagram of the surface heat flux coefficient distribution.

[0033] Figure 4 This is a schematic diagram illustrating the processing principle of the present invention.

[0034] Figure 5 Views of laser-processed surfaces with different ultrasonic ratios.

[0035] Figure 6 This is a flowchart of the processing of the present invention. Detailed Implementation

[0036] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0037] This invention proposes a heat reduction optimization method suitable for high-speed aircraft flying at high angles of attack. This heat reduction method is a surface treatment method, specifically using ultrasonic-assisted laser polishing to alter the surface roughness of the aircraft, thereby achieving heat reduction. The surface roughness is at the nanometer level; by changing the roughness, the heat flux distribution on the surface is altered, and the heat reduction effect is related to the distribution and size of the polishing strips. Under high angles of attack, this invention can reduce the surface heat flux of high-speed aircraft by more than 30%.

[0038] The surface nanopolishing provided by this invention involves ultrasonic-assisted laser polishing of the aircraft surface to achieve a roughness at the nanometer scale, thereby reducing near-wall viscous drag. For example, nanopolishing surface treatment can reduce the effects of aerodynamic heating on the nose cone, wings, leading edges of control surfaces, fuselage, and flat areas of high-speed aircraft.

[0039] The working principle of this invention will be explained below.

[0040] Technical Principle: For high-altitude, high-speed aircraft, when high-speed airflow passes over the nano-roughness surface of the aircraft, the surface viscosity is very low, reducing viscous drag near the near-wall boundary layer and thus lowering heat flux. Theoretically, full-surface nano-polishing would minimize wall heat flux; however, due to limitations in laser polishing spot size, achieving a completely smooth surface is difficult and the processing efficiency is very low, resulting in minimal benefits. Considering both processing efficiency and heat reduction effect, a semi-surface processing method is adopted. The smaller the surface roughness, the smaller the surface heat flux coefficient, and the better the heat reduction effect. Please refer to [link to relevant documentation]. Figure 1 In the transition zone between polished and unpolished strips, compression waves or shock waves can be induced, causing an increase in heat flux. Therefore, the strips should be continuously arranged on the rear surface of the aircraft and intermittent distribution should be avoided. Please refer to [link to relevant documentation]. Figure 3 .

[0041] The present invention will be further described below through preferred examples.

[0042] When the polishing strips meet certain arrangement and size requirements, they can achieve optimal heat reduction on the surface of high-speed aircraft. The polishing strips are prepared through ultrasonic-assisted laser polishing, including the following steps:

[0043] Step S1: Surface sandblasting to remove oil stains

[0044] Step S2: Divide the polishing strips

[0045] Step S3: Determine the laser scanning path, laser power, scanning speed, defocusing amount, and ultrasonic frequency.

[0046] Step S4: Continuous laser polishing

[0047] Step S5: Surface cleaning

[0048] Step S6: Check if the surface roughness reaches the nanometer level; if yes, end the process; if no, proceed to step S3 to continue execution.

[0049] The processing requires a surface roughness at the nanometer level; the smaller the roughness, the more significant the heat reduction effect. Furthermore, the polishing strips should preferably be arranged as far as possible on the rear surface of the aircraft; for example, all the polishing strips can be arranged on the rear surface, or most of the polishing strips can be arranged on the rear surface. The size of the polishing strips should be as large and continuous as possible, avoiding small strip distributions. Under high angles of attack, this arrangement of nano-polishing treatment has been proven through wind tunnel tests to reduce the aircraft's heat by more than 30%.

[0050] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0051] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A surface treatment optimization method suitable for aircraft heat reduction, characterized in that, Ultrasonic-assisted laser polishing is used to change the surface roughness of an aircraft, thereby altering the heat flow distribution on the aircraft surface. The surface roughness of the aircraft is at the nanometer level.

2. The surface treatment optimization method for aircraft heat reduction according to claim 1, characterized in that, Ultrasonic-assisted laser polishing is used to treat the surface of the aircraft's nose cone, wings, rudder leading edges, fuselage, and flat areas.

3. The surface treatment optimization method for aircraft heat reduction according to claim 1, characterized in that, The aircraft surface is processed using a semi-surface polishing method to form polished strips and non-polished strips.

4. The surface treatment optimization method for aircraft heat reduction according to claim 3, characterized in that, Polishing strips are arranged continuously on the rear surface of the aircraft, avoiding intermittent distribution.

5. The surface treatment optimization method for aircraft heat reduction according to claim 4, characterized in that, Polishing strips are arranged on the rear surface of the aircraft.

6. The surface treatment optimization method for aircraft heat reduction according to claim 5, characterized in that, Polishing strips are arranged on the rear surface of the aircraft.

7. The surface treatment optimization method for aircraft heat reduction according to claim 6, characterized in that, The polishing strips are mostly arranged on the rear surface of the aircraft.

8. The surface treatment optimization method for aircraft heat reduction according to claim 1, characterized in that, include: Step S1: Surface sandblasting to remove oil and dirt; Step S2: Divide the polishing strips; Step S3: Determine the laser scanning path, laser power, scanning speed, defocusing amount, and ultrasonic frequency; Step S4: Continuous laser polishing; Step S5: Surface cleaning; Step S6: Check if the surface roughness reaches the nanometer level; if yes, end the process; if no, proceed to step S3 to continue execution.

9. The surface of an aircraft, characterized in that, The surface of the aircraft is processed using any one of the surface treatment optimization methods for aircraft heat reduction as described in any one of claims 1 to 8.

10. An aircraft, characterized in that, Includes the surface of the aircraft as described in claim 9.

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