Special spoon-shaped wing section with ultra-low Reynolds number, high lift-drag ratio and low speed

Abstract

The invention provides a special spoon-shaped wing section with ultra-low Reynolds number, high lift-drag ratio and low speed. The thickness of the wing section before 60% of a chord is smaller and the thickness of the wing section after 60% of the chord is larger, so as to form a spoon shape geometry characteristic; the maximum relative thickness of the wing section before 60% of the chord is about 66% that of the wing section after 60% of the chord; the position of the maximum relative thickness of the wing section is at about 77% of the chord; the wing section has an area with reducing thickness at about 40% of the chord and the minimum relative thickness of the area of the wing section is about 35% of the maximum relative thickness of the wing section; the front part of the wing section is smaller in thickness and the rear part of the wing section is larger in thickness, so that the wing section has a good torque characteristic; under the Reynolds number of not greater than 10<4>, layer separation bubbles are small; the resistance of the wing section is greatly reduced, so that the wing section has a high lift-drag ratio and excellent pneumatic performance.

Description

technical field [0001] The invention belongs to the technical field of aerodynamics, and in particular relates to a special scoop-shaped airfoil with extremely low Reynolds number, high lift-to-drag ratio and low speed. Background technique [0002] The high-altitude aircraft uses electric energy converted from solar energy as the main energy source, mostly uses electric-driven propellers, and works within the altitude range of 20-30km. Its design goal is to achieve long-term fixed-point hovering or low-speed maneuvering flight. Due to the low air density in the adjacent space, the forward speed of the propeller is relatively small, so the propeller airfoil is basically in the special working condition of extremely low Reynolds number and Mach number 0-0.6; among them, the extremely low Reynolds number refers to ~10 4 magnitude Reynolds number. It can be seen from this that how to improve ~10 4 It is of great practical significance and application value to lower the lift-t...

AI Technical Summary

Problems solved by technology

[0003] Conventional low Reynolds number airfoils are mainly for Reynolds numbers greater than 10 5 Design, adopt conventional airfoil, when it is in extremely low Reynolds number, have the following problems: conventional airfoil surface laminar flow separation phenomenon is serious, airfoil lift-drag performance deterioration is severe, namely: when low Reynolds number, airfoil surface flow The laminar flow is dominant, and the laminar boundary layer is unstable. When it cannot overcome the reverse pressure gradient on the airfoil surface, the flow will separate and turn into turbulent flow, and then the turbulent flow will reattach to form a laminar flow separation bubble.

[0005] It can be seen that the current research on low Reynolds number airfoils focuses more on the flow separation phenomenon of conventional airfoils at low Reynolds numbers, and has not proposed a new wing with excellent aerodynamic performance at low Reynolds numbers. type, that is, it is impossible to fundamentally solve how to improve ~10 4 Reynolds number lower airfoil lift-to-drag ratio, thereby improving the aerodynamic performance of the airfoil

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