Resistance reduction design method after helicopter stub wing is additionally provided with detection equipment
After the detection equipment is installed on the helicopter short wing, the rectifier and rectification cover of the front of the design can be used to reduce the pneumatic resistance, solving the pneumatic resistance problem of the increase in detection equipment, and the improvement of the helicopter flight speed and the reduction of fuel consumption.
Patent Information
- Application Number
- CN202411434274.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-15
- Publication Date
- 2025-01-21
AI Technical Summary
After the detection equipment is installed on the short wing of the helicopter, the aerodynamic drag of the entire aircraft increases and the flight speed decreases, and the drag reduction design of the detection equipment is required.
Design a drag reduction design method by arranging front fairings and rear fairings on the windward and leeward sides of the detection equipment, combined with the aerodynamic shape of the short wings, to optimize the aerodynamic resistance of the detection equipment.
It effectively reduces aerodynamic resistance, increases the flight speed of the helicopter, and reduces fuel consumption. The drag coefficient is significantly reduced at different fuselage pitch angles.
Smart Images
Figure CN119329771A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of helicopter aerodynamics, and in particular relates to a drag reduction design method after a detection device is installed on a helicopter short wing. Background Art
[0002] In order to improve the capability of the helicopter, detection equipment is installed on the short wing. Since the detection equipment is completely exposed outside the fuselage and the detection equipment itself is large in size, the aerodynamic resistance of the entire aircraft increases and the flight speed decreases. In order to ensure the flight speed, the detection equipment on the short wing needs to be designed to reduce drag. Summary of the invention
[0003] The present invention proposes a drag reduction design method after a detection device is added to a helicopter short wing. The aerodynamic shape of the drag reduction design scheme of the detection device is integrated with the short wing. Compared with the state without drag reduction, the drag reduction design scheme has obvious drag reduction effect, which effectively improves the flight speed of the helicopter and reduces the fuel consumption rate.
[0004] In order to achieve the above object, the present invention adopts the following technical solution to achieve it.
[0005] A method for designing drag reduction after a detection device is installed on a helicopter short wing, the method comprising:
[0006] S1, perform aerodynamic drag analysis on the short wing with detection equipment installed to determine that a high pressure area is formed on the windward side of the detection equipment and a low pressure area is formed on the leeward side of the detection equipment;
[0007] S2, designing a front fairing, and setting the front fairing on the windward side of the detection device; both sides of the front fairing are tangentially connected to the detection device;
[0008] S3, design a rear fairing, and arrange the rear fairing on the leeward side of the detection device; both sides of the rear fairing are tangentially connected to the detection device.
[0009] Furthermore, the lower end surface of the front fairing is connected to the leading edge of the short wing.
[0010] Furthermore, in S2, the design parameters of the front fairing are specifically:
[0011] The extension length a of the front fairing at the front end of the detection device, the downward deflection angle θ of the upper end surface of the front fairing, the front fairing leading edge height c, and the angle γq between the two tangent lines of the front fairing leading edge surface;
[0012] Aerodynamic drag analysis is performed on the short wing, detection equipment and front fairing, and the design parameters of the front fairing with the smallest drag coefficient are selected.
[0013] Furthermore, the extension length a of the front fairing is the same as the front end height b of the detection device, and the front edge height c of the front fairing is b / 3.
[0014] Furthermore, the downward deflection angle θ of the upper end surface of the front fairing is 20°±2°, and the front fairing leading edge angle γq is 140°±2°.
[0015] Furthermore, in S3, the design parameters of the rear fairing are specifically:
[0016] The extension length d of the rear end of the rear fairing, the angle α between the upper and lower planes of the rear fairing, and the angle γh between the two tangent lines on the trailing edge of the rear fairing;
[0017] Aerodynamic drag analysis is performed on the short wing, detection equipment, front fairing and rear fairing, and the design parameters of the rear fairing with the smallest drag coefficient are selected.
[0018] Furthermore, the extension length d of the rear fairing is equal to the height h from the upper surface of the rear end of the detection device to the short wing surface.
[0019] Furthermore, the upper and lower angles α of the rear fairing are 25° to 30°, and the trailing edge angle γh of the rear fairing is 75°±2°.
[0020] The present invention proposes a method for designing drag reduction of helicopter stub-wing mounted equipment, which integrates the aerodynamic shape of the equipment with the stub wing, effectively reducing aerodynamic drag, wherein when the fuselage pitch angle is 0°, the drag coefficient is reduced by 5.5%; when the fuselage pitch angle is 2°, the drag coefficient is reduced by 5.3%; when the fuselage pitch angle is -2°, the drag coefficient is reduced by 5.9%; the drag reduction design scheme is installed and applied on a helicopter. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 A schematic diagram of installing a device above the short wing of a helicopter involved in the present invention;
[0022] Figure 2 It is a schematic diagram of the pressure coefficient distribution of the central section of the initial aerodynamic shape of the equipment involved in the present invention;
[0023] Figure 3 A schematic diagram of the velocity vector distribution of the central section of the initial aerodynamic shape of the device involved in the present invention;
[0024] Figure 4 It is a schematic diagram of a drag reduction design scheme for equipment involved in the present invention;
[0025] Figure 5 It is a schematic diagram of the pressure coefficient distribution of the central section of the equipment involved in the present invention after drag reduction;
[0026] Figure 6 It is a schematic diagram of the velocity vector distribution of the central section of the device after drag reduction according to the present invention;
[0027] Figure 7 It is a schematic diagram of a comparison curve of drag coefficients before and after drag reduction of the equipment involved in the present invention. DETAILED DESCRIPTION
[0028] The technical solution of the present invention is described in detail below with reference to the accompanying drawings.
[0029] An embodiment of the present invention provides a method for designing drag reduction after a detection device is installed on a helicopter short wing, the method comprising:
[0030] S1, perform aerodynamic drag analysis on the short wing with detection equipment installed to determine that a high pressure area is formed on the windward side of the detection equipment and a low pressure area is formed on the leeward side of the detection equipment;
[0031] S2, designing a front fairing, and setting the front fairing on the windward side of the detection device; both sides of the front fairing are tangentially connected to the detection device;
[0032] S3, design a rear fairing, and arrange the rear fairing on the leeward side of the detection device; both sides of the rear fairing are tangentially connected to the detection device.
[0033] The lower end surface of the front fairing is connected to the leading edge of the short wing.
[0034] In S2, the design parameters of the front fairing are as follows:
[0035] The extension length a of the front fairing at the front end of the detection device, the downward deflection angle θ of the upper end surface of the front fairing, the front fairing leading edge height c, and the angle γq between the two tangent lines of the front fairing leading edge surface;
[0036] Aerodynamic drag analysis is performed on the short wing, detection equipment and front fairing, and the design parameters of the front fairing with the smallest drag coefficient are selected.
[0037] The extended length a of the front fairing is the same as the front end height b of the detection equipment, and the leading edge height c of the front fairing is b / 3.
[0038] The downward deflection angle θ of the upper end surface of the front fairing is 20°±2°, and the leading edge angle γq of the front fairing is 140°±2°.
[0039] In S3, the design parameters of the rear fairing are as follows:
[0040] The extension length d of the rear end of the rear fairing, the angle α between the upper and lower planes of the rear fairing, and the angle γh between the two tangent lines on the trailing edge of the rear fairing;
[0041] Aerodynamic drag analysis is performed on the short wing, detection equipment, front fairing and rear fairing, and the design parameters of the rear fairing with the smallest drag coefficient are selected.
[0042] The extended length d of the rear fairing is equal to the height h from the upper surface of the rear end of the detection equipment to the short wing surface.
[0043] The upper and lower angles α of the rear fairing are 25°~30°, and the trailing edge angle γh of the rear fairing is 75°±2°.
[0044] Specifically,
[0045] Install detection equipment above the helicopter short wing, such as Figure 1 As shown, the basic shape of the device is a cube, and its aerodynamic resistance is very large, which leads to an increase in the aerodynamic resistance of the entire aircraft, thereby affecting the flight speed of the helicopter.
[0046] The calculation formula of aerodynamic resistance F and pressure coefficient distribution is as follows:
[0047]
[0048] Where: Cx is the drag coefficient, S is the windward area, ρ is the air density, V is the flight speed, P is the surface static pressure, P ∞ The static pressure of the incoming flow.
[0049] The aerodynamic shape of the equipment is designed to reduce drag. The steps of the drag reduction design are as follows:
[0050] 1. Determine the direction of drag reduction design
[0051] In order to obtain the drag coefficient of the initial aerodynamic shape of the equipment and determine the design direction of drag reduction, the aerodynamic drag analysis of the initial aerodynamic shape of the equipment was carried out, and the pressure coefficient distribution of the central section of the equipment was extracted, such as Figure 2 As shown. An obvious high-pressure area is formed on the windward side, and a low-pressure area is formed on the leeward side. At the same time, the upper part is affected by the windward side, resulting in a serious separation of the airflow above, such as Figure 3 As shown, a low-pressure area is also formed. Therefore, the drag reduction design direction is to reduce the high pressure at the front end of the device, increase the low pressure at the rear side, and reduce the airflow separation above.
[0052] 2. Reduce the design of high-voltage area at the front end of the equipment
[0053] Add a front fairing to the windward side of the front end of the device, such as Figure 4 As shown in the figure, a comparative analysis is conducted on the extension length a of the front fairing at the front end of the equipment, the downward deflection angle θ of the upper end surface of the front fairing, the height c of the leading edge of the front fairing, and the angle γq of the two tangents of the leading edge surface of the front fairing. The lower end surface of the front fairing is connected to the leading edge of the short wing (to ensure a smooth transition between the front fairing and the short wing to prevent the occurrence of step separation vortex), and both sides of the front fairing are tangently connected to the equipment body, and the scheme with the smallest drag coefficient is selected.
[0054] 3. Increase the low-voltage design on the rear side of the equipment
[0055] Add a rear fairing on the leeward side of the rear end of the device, such as Figure 4As shown, a comparative analysis of multiple schemes is conducted on the extension length d of the rear end of the rear fairing, the angle α between the upper and lower planes of the rear fairing, and the angle γh between the two tangents of the trailing edge of the rear fairing. The two sides of the rear fairing are tangentially connected to the equipment body, and the scheme with the smallest drag coefficient is selected.
[0056] 4. Drag reduction design
[0057] The equipment drag reduction design scheme involved in the present invention comprises the following steps: the extension length a of the front fairing is substantially equal to the height b of the front end of the equipment, the downward deflection angle θ of the upper end surface of the front fairing is approximately 20°, the height c of the leading edge of the front fairing is approximately b / 3, and the leading edge angle γq of the front fairing is approximately 140°; the extension length d of the rear fairing is equal to the height h from the upper surface of the rear end of the equipment to the short wing surface, the upper and lower angles α of the rear fairing can be 25°-30°, and the trailing edge angle γh of the rear fairing is approximately 75°.
[0058] 5. Drag reduction effect
[0059] The present invention proposes a method for designing a drag reduction device for adding equipment to a helicopter short wing, which integrates the aerodynamic shape of the drag reduction design scheme of the equipment with the short wing. The pressure distribution and velocity vector distribution of the central cross section of the drag reduction design scheme are as follows: Figure 5 , Figure 6 As shown in the figure, the high pressure area at the front is significantly reduced, the low pressure area at the rear is basically eliminated, and there is no airflow separation phenomenon above, which significantly reduces the aerodynamic resistance. Figure 7 As shown, compared with the original scheme, the drag reduction design scheme reduces the drag coefficient by 5.5% when the fuselage pitch angle is 0°; the drag coefficient is reduced by 5.3% when the fuselage pitch angle is 2°; and the drag coefficient is reduced by 5.9% when the fuselage pitch angle is -2°.
Claims
1. A method for designing drag reduction after installing a detection device on a helicopter short wing, characterized in that: The method comprises: S1, perform aerodynamic drag analysis on the short wing with detection equipment installed to determine that a high pressure area is formed on the windward side of the detection equipment and a low pressure area is formed on the leeward side of the detection equipment; S2, designing a front fairing, and setting the front fairing on the windward side of the detection device; both sides of the front fairing are tangentially connected to the detection device; S3, design a rear fairing, and arrange the rear fairing on the leeward side of the detection device; both sides of the rear fairing are tangentially connected to the detection device.
2. The method for designing drag reduction after adding detection equipment to a helicopter short wing according to claim 1, characterized in that: The lower end surface of the front fairing is connected to the leading edge of the short wing.
3. The method for designing drag reduction after adding detection equipment to a helicopter short wing according to claim 1, characterized in that: In S2, the design parameters of the front fairing are as follows: The extension length a of the front fairing at the front end of the detection device, the downward deflection angle θ of the upper end surface of the front fairing, the front fairing leading edge height c, and the angle γq between the two tangent lines of the front fairing leading edge surface; Aerodynamic drag analysis is performed on the short wing, detection equipment and front fairing, and the design parameters of the front fairing with the smallest drag coefficient are selected.
4. The method for designing drag reduction after installing detection equipment on a helicopter short wing according to claim 3, characterized in that: The extended length a of the front fairing is the same as the front end height b of the detection equipment, and the leading edge height c of the front fairing is b / 3.
5. The method for designing drag reduction after adding detection equipment to a helicopter short wing according to claim 3, characterized in that: The downward deflection angle θ of the upper end surface of the front fairing is 20°±2°, and the leading edge angle γq of the front fairing is 140°±2°.
6. The method for designing drag reduction after installing detection equipment on a helicopter short wing according to claim 1, characterized in that: In S3, the design parameters of the rear fairing are as follows: The extension length d of the rear end of the rear fairing, the angle α between the upper and lower planes of the rear fairing, and the angle γh between the two tangent lines on the trailing edge of the rear fairing; Aerodynamic drag analysis is performed on the short wing, detection equipment, front fairing and rear fairing, and the design parameters of the rear fairing with the smallest drag coefficient are selected.
7. The method for designing drag reduction after adding detection equipment to a helicopter stub wing according to claim 6, characterized in that: The extended length d of the rear fairing is equal to the height h from the upper surface of the rear end of the detection equipment to the short wing surface.
8. The method for designing drag reduction after adding detection equipment to a helicopter stub wing according to claim 6, characterized in that: The upper and lower angles α of the rear fairing are 25°~30°, and the trailing edge angle γh of the rear fairing is 75°±2°.