带螺旋桨平流层飞艇气动性能的数值分析

Numerical Analysis of Aerodynamic Performance for Stratospheric Airship with a Propeller

本文在CFD软件FLUENT6.3的计算平台上采用了Realizableκ-ε湍流模型和MRF技术数值模拟了带螺旋桨平流层飞艇的绕流场。着重分析了来流攻角为30°,厚度比为1:5的飞艇所受气动力系数以及艇体轴向和周向壁面的压力系数随螺旋桨推力系数的变化规律。结果表明,飞艇所受到的气动力系数总体随螺旋桨推力系数的增大而增大,飞艇表面摩擦阻力的变化量相对于形状阻力的变化量较小;螺旋桨与飞艇尾端的距离对飞艇气动特性也有很大的影响,该距离越小则影响越大;螺旋桨的抽吸和扰动作用主要集中在靠近螺旋桨的前方区域,随着螺旋桨推力系数的增大,螺旋桨对其前方区域的影响范围越广,飞艇尾部壁面压力系数的变化量也越大;螺旋桨的作用并没有很大程度的改变飞艇周向壁面压力分布规律,而是改变了周向壁面的压力系数大小。

The numerical simulation was carried out with FLUENT 6.3 by using Realizable k-ε turbulent model and MRF technology to analyze the flow field of a stratospheric airship with a propeller. The influence of thrust coefficients on the aerodynamic forces coefficients and pressure coefficients on the axial and circumferential surfaces was presented for a 1 ： 5 airship body under an angle of attack of 30 . The results show that the aerodynamic force coefficients increase with increasing thrust coefficients of the propeller. The variation of friction coefficient on the airship surface is relatively small comparing that of profile drag coefficient. The distance between the propeller and the tail of the airship has a great impact on the aerodynamic forces for the airship body. The smaller the distance is, the greater the effect is. The effects of propeller suction and disturbance are obvious mainly near the front of the propeller. With the increase of propeller thrust coefficient, the effective region of propeller is more extensive and the variation of pres- sure coefficient is greater. The pressure distribution profile in airship circumferential surface is not changed a lot, but the magnitude of pressure coefficient changes obviously with the increasing thrust coefficient.