翼身融合背撑发动机反推绕流流场数值研究

Numerical investigation on thrust reverse flow field of podded engines on blended wing body

基于RANS(Reynolds averaged Navier-Stokes)方法,采用SST(shear stress transport)湍流模型和进排气边界条件,对翼身融合背撑发动机反推绕流流场进行了数值模拟,探究得到反推气流动力影响下机体气动载荷的变化规律,并评估了不同发动机功率下反推的增阻效果,以及对进气道流场畸变特性进行了初步的分析。结果表明:反推气流会显著影响机体气动载荷的分布状况,发动机前方的机体表面压力逐渐增大,经过反推出流带后,表面压力急剧减小,沿展向其影响逐渐减弱;在一定范围内,反推气流的轴向折流角越大,对气动载荷分布的影响越剧烈,增阻效果也越好;轴向折流角和来流马赫数的变化会影响进气道流场畸变特性。

Reverse thrust is an efficient deceleration braking method to shorten the taxiing distance.Based on RANS(Reynolds averaged Navier-Stokes)method,SST(shear stress transport)turbulence model and inlet/exhaust boundary conditions were used to simulate the flow field around the thrust reverser.The variation law of aerodynamic load under the influence of the thrust reverser was explored, the drag increasing effect of the thrust reverser under different engine power was evaluated, and the distortion characteristics of the inlet flow field were preliminarily analyzed.The results showed that the thrust reverser flow can significantly affect the distribution of aerodynamic load, and the surface pressure in front of the engine increased gradually.Behind the thrust reverser flow belt, the surface pressure decreased sharply, and the influence weakened along spanwise direction.In a certain range,the larger axial deflection angle of the thrust reverser flow indicated the stronger influence of thrust reverser flow on the distribution of aerodynamic load, and the better drag increasing effect.The distortion characteristics of the inlet flow field would be affected by the changes of the axial deflection angle of reverse flow and the Mach number of freestream.