基于等效盘模型的滑流对涡桨飞机气动性能的影响

 推导了螺旋桨等效盘模型的相关气动计算公式，建立了考虑螺旋桨桨盘前后压差和滑流旋转速度以及变桨距、螺旋桨转速等因素的较通用的等效盘模型。将等效盘边界条件应用于NAPA软件进行了三维流场计算,分析了流场计算结果和流场特征；并采用某螺旋桨的试验数据对等效盘模型进行了检验，推力和扭矩的计算值与试验结果吻合较好，表明该等效盘模型能较为准确地模拟螺旋桨的推力、扭矩、压力变化和旋转速度变化，能在一定程度上替代真实螺旋桨的气动效应。然后应用该等效盘模型对某四发涡桨飞机的全机三维流场进行了数值模拟研究，分析了螺旋桨滑流对全机流场特征的影响，给出了滑流对全机升、阻力系数的影响量。计算结果表明，螺旋桨后形成的涡能改变下游的流场并使机翼表面流线偏转，螺旋桨滑流能明显改变机翼表面的压力分布，使全机升、阻力系数增大，且滑流强度越大，效果越明显。

Propeller Slipstream Effects on Aerodynamic Performance of Turbo-prop Airplane Based on Equivalent Actuator Disk Model

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.