高速进气道抛罩过程内流场演化特性研究

为探究进气道整流罩打开过程中内流场的演化规律,针对下颌式进气道及其配套整流罩,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,堵罩时,整流罩前端发展出V形激波,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,开罩过程中,整流罩前端的V形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且大于稳定状态。对于开罩过程流动准定常且内流道无大分离区的流场,进气道在V形激波打在唇口时完成起动且整流罩在此后不影响内流场流动。假设的匀加速转动与重构出的真实转动吻合较好,对于更精确的运动过程模拟可采用三次函数的角速度变化律。

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

To explore internal flow field on the inlet cover separation process, the separation process simulation was based on overset method. The evolution process of internal flow field and characteristic flow field structure were analyzed in detail. 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. On the separation process, the V-swept shock wave and the backward facing step both affect the internal flow, and the mass flow rate at throat reaches its peak at intermediate moment and is greater than that at a stable moment. 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. The assumed constant acceleration rotation was consistent with the reconstructed real rotation, and a more accurate motion simulation suggests the cubic angular velocity function.