高超声速主流中横向喷流干扰非定常特性研究

脉冲发动机产生的横向喷流往往伴随着非定常效应,由于其持续时间非常短,给流场模拟和测量带来很大的困难.目前在地面设备中难以进行精确的试验,本文采用数值模拟方法对横向喷流的非定常效应进行了研究.重点对发动机启动和关车过程中典型时刻的流场进行了细致的刻画,分析了流动参数和模型气动力系数的动态变化过程,并给出了喷流压比和攻角变化所带来的影响.研究表明,喷流启动和关闭过程中,飞行器所呈现出的动态气动特性与稳态喷流时有着明显的差异,尤其是压心位置和法向力系数将发生显著的变化.在飞行器设计中,必须从安全控制的角度出发,考虑这一非定常效应的影响.

Unsteady characteristic research of lateral jet in hypersonic external flow

Impulsive lateral jet produced by attitude control engine is often combined with unsteady phenomenon. As an instant process, it is difficult to simulate and measure this unsteady flow in wind tunnel, so CFD analyze technique is applied. The unsteady characteristic of lateral jet interaction produced by impulsive engine is researched, startup and cutoff process of impulsive engine is emphatically simulated, the instant flow structure is described carefully, the dynamic process of flow parameters and aerodynamic coefficients of the model are analyzed, the effect of jet pressure ratio and attack angle are also discussed. It's indicated that during the process of jet startup and cutoff, difference on aerodynamic performance of the aerocraft is displayed, compared with the situation of steady jet. Especially pressure center and normal force coefficient is changed remarkably. So the effect of unsteady jet should be paid attention in aerocraft design.