Abstract:

An equivalent actuator disk model of airplane propeller is presented, which takes into consideration such factors as the pressure jump across the disk, swirl velocity of slipstream, variablepitch propeller, and rotating speed of rotor, etc. The model is placed in the NavierStokes program NAPA and the flow field around the actuator disk is calculated. The flow characteristics are discussed and the validation shows that the computational results of thrust and torque are in good agreement with the testing data. It can be concluded that the actuator disk model can correctly predict the thrust, torque and the pressure and swirl velocity changes of the propeller. The model can be used as a simplified but realistic one in the analysis of propeller slipstream interference effects. Then the three dimensional flow field around a fourengine turboprop airplane is simulated using the actuator disk model. The effects of propeller slipstream on the characteristics of the flow field are analyzed and the increments of lift and drag coefficients caused by slipstream are presented. The results show that the vortices caused by propellers can change the flow field and produce deflection of streamlines on wing surface. The propeller slipstream can alter the pressure distributions on wing surface evidently, which will increase the lift and drag coefficients of the airplane, and the greater the slipstream intensity, the greater the increment.

Key words: propeller , slipstream,  , equivalent , actuator , disk,  , turboprop , airplane,  , boundary , condition,  , numerical , simulation,  , computational , fluid , dynamics , (CFD)