Rapid drainage aircraft wheel design method for aviation aircraft wheel

Abstract

The invention relates to the technical field of aviation aircraft wheel design, in particular to a rapid drainage aircraft wheel of an aviation aircraft wheel and a design method thereof, and the design method comprises the steps that the inner surface of a hub is a divergent flow guide surface, and a drainage gap is formed between the inner surface of the hub and a heat screen. According to the invention, through the design of the divergent flow guide surface and the drainage gap, the accumulated water of the airplane wheel in a special environment can be rapidly and actively drained.

Description

Technical Field

[0001] This invention relates to the field of aircraft wheel design technology, specifically to an aircraft wheel with rapid drainage and its design method. Background Technology

[0002] Aircraft landing gear plays a crucial role in takeoff and landing operations, facing harsh conditions such as seawater splash and rainwater leakage. Water accumulation in the landing gear structure can lead to reduced braking performance of the landing gear brakes and accelerated corrosion of metal components, seriously impacting aircraft flight safety and the service life of the landing gear. However, existing technologies for drainage in conventional aircraft landing gear structures have the following shortcomings: 1. Insufficient fluid guidance: The inclination angle of the drainage channel is not matched with the speed of the impeller, resulting in low utilization of centrifugal force.

[0003] 2. Obstructed drainage path: Traditional wheel hub cavity drainage channels are structurally blocked, reducing drainage efficiency.

[0004] 3. Significant capillary effect: If the gap between the heat insulation screen and the hub is too small, the surface tension will cause water to accumulate, affecting the heat insulation performance and aggravating the electrochemical corrosion of metal parts.

[0005] 4. Risk of thermal plug failure: Conventional thermal plug installation structures are easily covered by water accumulation, causing a delay in temperature response.

[0006] Therefore, there is a need to provide a design method for aircraft wheels with rapid drainage to solve the above problems. Summary of the Invention

[0007] To address the problem of insufficient fluid guidance in existing aircraft wheel structures during drainage, this invention provides a design method for a fast drainage aircraft wheel to solve the existing problems.

[0008] The first aspect of the present invention provides a rapid drainage wheel for aircraft wheels, used for draining water accumulated inside the wheel in high humidity and high salt spray environments. The technical solution includes: making the inner surface of the wheel hub a gradually expanding guide surface, and providing a drainage gap between the inner surface of the wheel hub and the heat insulation screen.

[0009] A further technical solution of the present invention is that the hot melt plug of the wheel is set on the inner surface of the wheel.

[0010] A further technical solution of the present invention is that the angle between the gradually expanding guide surface and the hub axis is the expansion angle of the gradually expanding guide surface, and the expansion angle is 3~5°.

[0011] A further technical solution of the present invention is that a hydrophobic coating or an oxide layer is provided on the inner surface of the wheel hub.

[0012] A second aspect of the present invention provides a method for designing a fast-drainage aircraft wheel, comprising: The relationship between the drainage gap and the discharge flow rate of the accumulated water is obtained based on the minimum radius of the gradually expanding guide surface in the hub. The drainage gap is designed based on the relationship between the drainage gap and the flow rate of accumulated water. The water discharge velocity is obtained based on the minimum radius of the gradually expanding guide surface in the hub, the designed drainage gap, and the corresponding water discharge flow rate. The hydraulic diameter is obtained based on the minimum radius of the gradually expanding guide surface in the hub and the designed drainage gap. The Reynolds number is obtained based on the hydraulic diameter and the discharge velocity of the accumulated water, and the friction coefficient of the discharged water is obtained based on the Reynolds number. The expansion angle of the gradually expanding guide surface is designed based on the friction coefficient of the water discharge, the water discharge velocity, the hydraulic diameter, the turbine speed, and the minimum radius of the gradually expanding guide surface in the hub. The hub of the drainage impeller is designed based on the drainage gap and the expansion angle of the gradually expanding guide surface.

[0013] A further technical solution of the present invention is that the relationship between the drainage gap and the flow rate of the accumulated water is expressed as follows:

[0014] In the formula, Represents the Weber number; Indicates the flow rate of the accumulated water; This indicates the minimum radius of the gradually expanding guide surface in the wheel hub; Indicates the drainage gap; This represents the surface tension coefficient of water.

[0015] A further technical solution of the present invention is that the expression for the drainage velocity of the accumulated water is:

[0016] In the formula, Indicates the flow rate of the drained water; Indicates the flow rate of the accumulated water; This indicates the minimum radius of the gradually expanding guide surface in the wheel hub; Indicates the drainage gap.

[0017] A further technical solution of the present invention is that the expression for the hydraulic diameter is:

[0018] In the formula, Indicates the hydraulic diameter; This indicates the minimum radius of the gradually expanding guide surface in the wheel hub; Indicates the drainage gap.

[0019] A further technical solution of the present invention is that the expressions for the Reynolds number and the friction coefficient are as follows:

[0020]

[0021] In the formula, Represents the Reynolds number; Indicates the flow rate of the drained water; Indicates the hydraulic diameter; ν Indicates the kinematic viscosity of water; This represents the friction coefficient.

[0022] A further technical solution of the present invention is the expression for the expansion angle of the gradually expanding guide surface:

[0023]

[0024] In the formula, ω Indicates the rotational speed of the rotor; θ Indicates the expansion angle of the gradually expanding guide surface; f This represents the acceleration caused by resistance during the drainage process of accumulated water; Indicates the friction coefficient; Indicates the flow rate of the drained water; Indicates the hydraulic diameter.

[0025] The beneficial effects of this invention are: 1. This invention significantly improves the drainage efficiency of aircraft wheels by designing the inner surface of the wheel hub as a gradually expanding guide surface and setting a gap between the heat shield and the inner surface of the wheel hub. It can remove accumulated water in a short time through centrifugal action, reducing the negative impact of accumulated water on the braking performance and components of the wheels.

[0026] 2. While improving the drainage function, the present invention also takes into account the heat insulation and structural strength of the wheel by setting the gap between the heat insulation screen and the inner surface of the hub, the low-resistance drainage channel system and the protruding design of the hot melt plug, thus ensuring the stable operation of the wheel in complex environments.

[0027] 3. This design method has high operability and adaptability, and can be applied to the design of aircraft wheels of different models and specifications, and has broad application prospects. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the overall structure of an embodiment of a fast drainage aircraft wheel according to the present invention; Figure 2 for Figure 1 A partially enlarged schematic diagram of the gradually expanding guide surface on the inner side of the wheel hub; Figure 3 for Figure 1 Schematic diagram of the drainage gap between the inner surface of the wheel hub and the heat shield; Figure 4 A comparative diagram of drainage channels before and after reducing structural resistance; Figure 5 A schematic diagram of the protruding design of the hot melt plug. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] An embodiment of the present invention is a fast drainage aircraft wheel, such as... Figure 1 As shown, it includes: a gradually expanding guide surface on the inner surface of the hub, a drainage gap between the inner surface of the hub and the heat shield, and a hot plug protruding from the inner surface of the wheel.

[0032] For example, in one specific embodiment, the angle between the gradually expanding guide surface and the hub axis is the expansion angle of the gradually expanding guide surface, which is 3~5°.

[0033] For example, in one specific implementation, the drainage channel is optimized: the inner surface of the hub minimizes drive keys that cause abrupt changes in the drainage channel cross-section. The grooves on the inner wall of the aircraft wheel hub are prone to water accumulation. The drive keys on the inner wall of the aircraft wheel hub transmit braking torque. Grooves are designed to reduce weight while ensuring functional performance. When designing weight-reducing grooves on the inner wall of the hub, a drainage slope is usually designed to guide water flow towards the hub opening. The hub cylinder wall is flared towards the hub opening to ensure that water is thrown out under the action of centrifugal force during the wheel's rotation. Figure 4 As shown in b, in this embodiment, the grooves at the ends of the web and drive key on the inner wall of the hub are removed. Even though the drive key and web are continuous, this design reduces water accumulation and allows for rapid drainage while the wheel is rotating. Simultaneously, the surface roughness of the inner wall of the wheel is reduced, and a hydrophobic coating process is used to reduce friction resistance during water drainage. That is, all inner wall surfaces of the hub should be smooth to prevent water from adhering to burrs or gaps due to surface tension, thereby ensuring that water entering the inner cavity of the hub is drained as quickly as possible. Specifically, a hydrophobic coating or oxide layer is provided on the inner surface of the hub. In this embodiment, the hydrophobic coating is generated on the inner surface of the hub using a spraying method or a vapor deposition method. When the hub material is aluminum or magnesium alloy, surface anodizing is used to form an oxide layer on the inner surface of the hub, controlling the thickness of the oxide layer to be 50±5nm.

[0034] For example, in one specific implementation, such as Figure 5 As shown, the design ensures that the fusible plug is higher than the inner surface of the hub after assembly. The fusible plug is accurately installed on the wheel surface, ensuring its height meets design requirements and that it is securely and reliably installed. The design of the fusible plug being 1-2mm higher than the inner surface of the hub prevents water accumulation around it and ensures its proper function during wheel operation. The protruding fusible plug does not negatively impact the overall structure and operation of the wheel, avoiding factors that hinder rapid drainage, such as localized water accumulation. The core function of the aircraft wheel hub fusible plug is to ensure tire pressure relief at high temperatures; while ensuring this core function, it is necessary to prevent water accumulation and blockage. The aircraft wheel hub structure typically includes multiple fusible plugs (3-6 are acceptable) evenly distributed along the circumference, ensuring that regardless of the wheel's angle, at least one fusible plug is always located at or near the lowest point. This allows water that has entered the hub to naturally flow to the lowest point under gravity. The edges of the fusible plug holes are usually chamfered to facilitate drainage.

[0035] An embodiment of the present invention provides a design method for a fast-drainage aircraft landing gear, comprising: S1. Design drainage gap: Specifically, based on the minimum radius of the gradually expanding guide surface in the hub, the relationship between the drainage gap and the water discharge flow rate is obtained; based on the relationship between the drainage gap and the water discharge flow rate, the drainage gap is designed.

[0036] For example, in one specific embodiment, the relationship between the drainage gap and the water discharge flow rate is obtained based on the minimum radius of the gradually expanding guide surface in the hub; the steps for designing the drainage gap based on this relationship are as follows: like Figure 3 As shown, during the design phase, the drainage gap between the heat shield and the inner surface of the wheel hub is controlled. To reduce the impact of surface tension on drainage, the parameters of this drainage channel section must meet the following requirements: (1) In the formula, Let represent the Weber number; where the formula for calculating the Weber number is: (2) In the formula, Indicates the flow rate of the drained water; Indicates the hydraulic diameter; In this embodiment, the surface tension coefficient of water is represented. .

[0037] The expression for the drainage velocity is: (3) In the formula, Indicates the flow rate of the drained water; Indicates the flow rate of the accumulated water; This indicates the minimum radius of the gradually expanding guide surface in the wheel hub; Indicates the drainage gap.

[0038] The expression for the hydraulic diameter is: (4) In the formula, Indicates the hydraulic diameter; This indicates the minimum radius of the gradually expanding guide surface in the wheel hub; Indicates the drainage gap.

[0039] The relationship between the drainage gap and the flow rate of the accumulated water can then be derived as follows: (5) In the formula, Represents the Weber number; Indicates the flow rate of the accumulated water; This indicates the minimum radius of the gradually expanding guide surface in the wheel hub; Indicates the drainage gap; This represents the surface tension coefficient of water.

[0040] In this embodiment, the water discharge flow rate It is 0.0265 m 3 / s, the minimum radius of the gradually expanding guide surface in the hub If the value is 0.233m, then the calculated value is... ≥0.0022m=2.2mm.

[0041] S2, Design the expansion angle of the gradually expanding guide surface; Specifically, the discharge velocity of the accumulated water is obtained based on the minimum radius of the gradually expanding guide surface in the hub, the designed drainage gap, and the corresponding discharge flow rate; the hydraulic diameter is obtained based on the minimum radius of the gradually expanding guide surface in the hub and the designed drainage gap; the Reynolds number is obtained based on the hydraulic diameter and the discharge velocity of the accumulated water, and the friction coefficient of the discharged water is obtained based on the Reynolds number; the expansion angle of the gradually expanding guide surface is designed based on the friction coefficient of the discharged water, the discharge velocity of the accumulated water, the hydraulic diameter, the wheel speed, and the minimum radius of the gradually expanding guide surface in the hub.

[0042] First, during the manufacturing and assembly process, high-precision measurement and positioning technologies are used to strictly control the clearance tolerance within ±0.5.

[0043] For example, in one specific embodiment, the step of obtaining the water discharge velocity based on the minimum radius of the gradually expanding guide surface in the hub, the designed drainage gap, and the corresponding water discharge flow rate is as follows: Substitute the drainage gap designed in step S1 into formula (3) to obtain the water discharge velocity. .

[0044] For example, in one specific embodiment, the step of obtaining the hydraulic diameter based on the minimum radius of the gradually expanding guide surface in the hub and the designed drainage gap is as follows: Substitute the drainage gap designed in step S1 into formula (4) to obtain the hydraulic diameter. .

[0045] For example, in one specific embodiment, the steps for obtaining the Reynolds number based on the hydraulic diameter and the discharge velocity of the accumulated water are as follows: (6) In the formula, ν Indicates the kinematic viscosity of water; the obtained flow rate of discharged water. and hydraulic diameter Substituting into formula (6) yields the Reynolds number. .

[0046] For example, in one specific embodiment, the step of obtaining the friction coefficient of water discharge based on the Reynolds number is as follows: (7) In the formula, This represents the friction coefficient along which water is drained.

[0047] For example, in one specific embodiment, the steps for designing the expansion angle of the gradually expanding guide surface based on the friction coefficient of the discharged water, the discharged water velocity, the hydraulic diameter, the turbine speed, and the minimum radius of the gradually expanding guide surface in the hub are as follows: like Figure 2 As shown, during the design, the angle between the tapered wall of the gradually expanding structure and the axis is controlled. θFor water to drain smoothly from the turbine, the following conditions must be met: (8) (9) In the formula, ω Indicates the rotational speed of the rotor; θ Indicates the expansion angle of the gradually expanding guide surface; f This represents the acceleration caused by resistance during the drainage process of accumulated water; Indicates the friction coefficient; Indicates the flow rate of the drained water; Indicates the hydraulic diameter.

[0048] The expression for the rotor speed is: (10) In the formula, This indicates the braking speed, which is 300 km / h in this embodiment. This indicates the rolling radius of the wheel after the tires are installed; in this embodiment, it is 0.5m. This embodiment should ensure... θ ≥3°, but taking into account other factors such as wheel strength, the included angle is... θ It should generally not be too large.

[0049] S3. Design the hub of the drainage impeller; Specifically, based on the drainage gap and the expansion angle of the gradually expanding guide surface, the hub of the drainage wheel can be obtained by using high-precision machining equipment to manufacture the gradually expanding centrifugal guide structure inside the hub according to the design requirements of angle and size.

[0050] It should be noted that designing the inner side of the wheel hub as a gradually expanding guide surface (i.e., a "trumpet mouth") utilizes the centrifugal force generated during wheel rotation to quickly guide accumulated water to the wheel edge for discharge. By optimizing the angle, accumulated water can be removed from the wheel in the shortest possible time, preventing water residue inside the wheel hub. By designing the size of this drainage gap, local water accumulation caused by capillary action can be effectively reduced, preventing water from obstructing the drainage channel and reducing the heat insulation efficiency of the heat shield. By reducing unnecessary protrusions and depressions, and optimizing the shape and layout of the drainage channel, the local resistance when water is discharged from the wheel under centrifugal force is reduced. In this embodiment, a protrusion refers to a surface higher than the end face of the drive key on the inner wall of the aircraft wheel hub, while a depression refers to a surface lower than the end face of the drive key on the inner wall of the aircraft wheel hub. Both protrusions and depressions are detrimental to the rapid drainage of the aircraft wheel. While ensuring structural performance, the slotting of the drive key should be minimized. Furthermore, guide rails need to be installed on the drive key via screw connections. The screws fixing the guide rails should not be higher than the end face of the drive key on the inner wall of the hub. While ensuring the fixing function, the number of guide rail screws should be reduced, generally not exceeding three. Simultaneously, a hydrophobic coating is used to reduce the surface roughness of the inner wall of the wheel, thereby reducing the frictional resistance during water drainage. The fusible plug is designed to protrude from the inner surface of the wheel. This protrusion prevents water from accumulating around the fusible plug and ensures that it functions properly during wheel operation.

[0051] 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 rapid drainage aircraft wheel, characterized in that, include: The inner surface of the hub is a gradually expanding guide surface, and a drainage gap is provided between the inner surface of the hub and the heat shield.

2. The aircraft wheel with rapid drainage according to claim 1, characterized in that, The hot melt plug of the wheel is set on the inner surface of the wheel.

3. The aircraft wheel with rapid drainage according to claim 1, characterized in that, The angle between the gradually expanding guide surface and the hub axis is the expansion angle of the gradually expanding guide surface, which is 3~5°.

4. The aircraft wheel with rapid drainage according to claim 1, characterized in that, The inner surface of the wheel hub is coated with a hydrophobic coating or an oxide layer.

5. A design method for a fast-drainage aircraft wheel as described in claims 1-4, characterized in that, include: The relationship between the drainage gap and the discharge flow rate of the accumulated water is obtained based on the minimum radius of the gradually expanding guide surface in the hub. The drainage gap is designed based on the relationship between the drainage gap and the flow rate of accumulated water. The water discharge velocity is obtained based on the minimum radius of the gradually expanding guide surface in the hub, the designed drainage gap, and the corresponding water discharge flow rate. The hydraulic diameter is obtained based on the minimum radius of the gradually expanding guide surface in the hub and the designed drainage gap. The Reynolds number is obtained based on the hydraulic diameter and the discharge velocity of the accumulated water, and the friction coefficient of the discharged water is obtained based on the Reynolds number. The expansion angle of the gradually expanding guide surface is designed based on the friction coefficient of the water discharge, the water discharge velocity, the hydraulic diameter, the turbine speed, and the minimum radius of the gradually expanding guide surface in the hub. The hub of the drainage impeller is designed based on the drainage gap and the expansion angle of the gradually expanding guide surface.

6. The design method for a fast-drainage aircraft landing gear according to claim 5, characterized in that, The relationship between the drainage gap and the flow rate of accumulated water is as follows: In the formula, Represents the Weber number; Indicates the flow rate of the accumulated water; This indicates the minimum radius of the gradually expanding guide surface in the wheel hub; Indicates the drainage gap; This represents the surface tension coefficient of water.

7. The design method for a fast-drainage aircraft landing gear according to claim 5, characterized in that, The expression for the drainage velocity of the accumulated water is: In the formula, Indicates the flow rate of the drained water; Indicates the flow rate of the accumulated water; This indicates the minimum radius of the gradually expanding guide surface in the wheel hub; Indicates the drainage gap.

8. The design method for a fast-drainage aircraft landing gear according to claim 5, characterized in that, The expression for the hydraulic diameter is: In the formula, Indicates the hydraulic diameter; This indicates the minimum radius of the gradually expanding guide surface in the wheel hub; Indicates the drainage gap.

9. The design method for a fast-drainage aircraft landing gear according to claim 5, characterized in that, The expressions for the Reynolds number and the friction coefficient are: In the formula, Represents the Reynolds number; Indicates the flow rate of the drained water; Indicates the hydraulic diameter; ν Indicates the kinematic viscosity of water; This represents the friction coefficient.

10. A method for designing a fast-drainage aircraft landing gear according to claim 5, characterized in that, The expression for the expansion angle of the gradually expanding guide surface: In the formula, ω Indicates the rotational speed of the rotor; θ Indicates the expansion angle of the gradually expanding guide surface; f This represents the acceleration caused by resistance during the drainage process of accumulated water; Indicates the friction coefficient; Indicates the flow rate of the drained water; Indicates the hydraulic diameter.

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