高速进气道抛罩过程内流场演化特性研究

Internal Flow Field Evolution Characteristics for Inlet Cover Separation of High Speed Inlet

关键词:  进气道整流罩  重叠网格法  内流场  扫掠激波  后向台阶

Key words:  Inlet cover  Overset method  Internal flow field  Swept shock wave  Backward facing step

摘要:

为探究进气道整流罩打开过程中内流场的演化规律，基于重叠网格法求解N-S方程详细分析了抛罩过程中内流场演化过程与特征流场结构。研究表明，在进气道封堵时，整流罩前端发展出V型激波，整流罩尾部形成后向台阶且产生一对涡矢量方向相反的流向涡；在整流罩打开过程中，整流罩前端的V型激波与尾部的后向台阶均会对内流场流动产生影响，捕获流量在中间某时刻达到峰值后下降至稳定状态。若开罩过程中的流场满足流动准定常且内流道无大分离区的条件，进气道在V型激波与唇口恰好相交时完成起动且整流罩的运动在此后不影响内流场流动。假设的整流罩匀加速转动过程与真实运动吻合较好，模拟更精确的整流罩运动可采用三次函数的角速度变化律。

Abstract:

To explore internal flow field on the inlet cover separation process， based on overset method to solve N-S equation， the evolution process of internal flow field and characteristic flow field structure were analyzed in detail during inlet cover separation. Numerical simulations show that a V- swept shock wave is formed at the front of the inlet cover， and a backward facing step that induces a pair of streamwise vortexes with the opposite vectors is formed at the rear of inlet cover when the inlet is blocked. On the separation process， the V-swept shock wave and the backward facing step both affect the internal flow. The mass flow rate at throat reaches its peak at intermediate moment then drops to a stable value. If the flow is quasi-steady and no large separation zone exists in the inner inlet during the separation process， inlet starts when the V-swept shock wave meets the lip line， and the motion of inlet cover no longer affects the internal flow field afterwards. The assumed constant acceleration rotation was consistent with the real rotation， and a more accurate motion simulation suggests the cubic angular velocity function.