Research on stall deceleration for nacelle strake design of engine propeller aircraft

The effect of nacelle strake on stall was studied by numerical simulation. Numerical simulation and wind tunnel test showed that in the state of zero thrust, after a large four engine propeller aircraft exceeded the stall angle of attack, the wings between the internal and external engines first separated and quickly advanced to the leading edge of the wing, and the lift loss reached about 30%. In order to limit the separation speed of the wing, a nacelle strake was installed inside the outboard engine nacelle. The simulation results showed that the stall characteristics were significantly improved at the optimal design position, the lift loss after stall was reduced by about 50% compared with the state without nacelle strake, and the stall angle of attack did not change significantly. Different installation positions of nacelle strakes had obvious differences in improving stall; movement from the best position to the circumferential direction and propeller direction caused the failure of nacelle strake. Movement to the wing direction wa effective to improve the wing separation speed, but it significantly reduced the stall angle of attack. After moving to the wing direction, the influence of circumferential position was reduced. A wind tunnel test was carried out to verify the landing configuration in zero-thrust condition according to the optimal design position. After adding the nacelle strake, the lift loss of the airfoil after stall was reduced from 0.92 to about 0.42, and the lift loss was reduced by 54%, which was basically consistent with the numerical simulation conclusion.