High-lift-force laminar flow aerofoil profile with low-resistance and high-drag-divergence Mach number

Abstract

The invention discloses a high-lift-force laminar flow aerofoil profile with a low-resistance and high-drag-divergence Mach number. The radius of a leading edge is 0.025, a maximum camber of 0.031 exists at a 52.8% chord-length position of the airfoil profile, and a maximum thickness of 0.150 exists at a 40.5% chord-length position of the airfoil profile. Because the radius of the leading edge of the aerofoil profile is large, a large favorable pressure gradient is ensured, and the favorable pressure gradient is kept at about 10% of that of the leading edge; the upper surface of the aerofoil profile is in a suitable small-curvature shape, thereby avoiding the rapid recovery of pressure; after the pressure of the leading edge is minimum, in a 20% chord length range, a situation that the pressure distribution pattern has a small adverse pressure gradient is allowed, and the remarkable weak inverse pressure in the section both keeps the stable development of a laminar flow area and facilitates the pressure recovery of a trailing edge, so that an airflow, after being slowed down slowly, enters a stable and linear smooth accelerating process again. The maximum camber position and maximum thickness position of the aerofoil profile relatively stand backwards, so that a situation that a small section of smooth favorable pressure gradient exists behind the weak adverse pressure is ensured, thereby facilitating the continued development of a laminar region, and increasing the lift force.

Description

technical field [0001] The invention relates to the technical field of laminar flow airfoils, in particular to a high-lift laminar flow airfoil with low resistance and high resistance divergent Mach number. Background technique [0002] With the continuous improvement of modern aircraft design technology, future fighter jets must have the ability to strike quickly while having good cruise performance. The U.S. Defense Advanced Research Projects Agency (DARPA) believes that the next generation of stealth aircraft can fly for intelligence, surveillance and reconnaissance missions at an altitude of 18,000 meters to 25,000 meters close to enemy territory at a subsonic speed for a long time, which can avoid most artillery or missiles blow. Therefore, high-altitude and long-endurance unmanned aerial vehicles (UAVs) emerged as the times require. This type of aircraft can perform high-subsonic cruise at medium and high altitudes with a large aspect ratio and small back-sweep shape,...

AI Technical Summary

Problems solved by technology

At the same time, the low design Reynolds number can ensure that the airfoil can maintain laminar flow in most areas, but for high-lift airfoils, shock waves are likely to occur if the cruise speed is too high, inducing airflow separation, resulting in loss of lift coefficient

In addition, if the airfoil has a larger chord-wise range of pressure gradient on the upper surface that is conducive to the development of laminar flow, the reverse pressure gradient at the rear of the upper surface of the airfoil will become larger, so that airflow separation and stall are more likely to occur. All these factors mentioned above bring great challenges to airfoil design.

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