左行运动激波主导的管内流动特性研究

Flow Characteristics of Pipe Dominated by Leftward Moving Shock

关键词:  运动激波  流动特征  流动分离  激波/边界层干扰  数值模拟

Key words:  Moving shock  Flow characteristics  Flow separation  Shock/boundary layer interaction  Numerical simulation

摘要:

为了分析左行运动激波主导的管内流动特征，本文采用非定常数值仿真方法，对亚声速进口条件下等直管道内左行运动激波传播与演化特性、左行运动激波/边界层干扰特征开展研究。研究结果表明：在出口周期性强压力脉动干扰下管内存在连续的左行运动激波，该左行运动激波传播特征具有相似性，激波强度、传播速度按幂函数规律衰减。气流经过左行运动激波后总压、总温、静压阶跃式升高，随后受膨胀波影响气流总压、总温、静压下降；左行运动激波/边界层干扰诱发形成翼型回流区，该回流区随运动激波强度衰减逐渐减小。理论与数值分析表明存在左行运动激波后速度为零和运动激波两侧总压相等的两个临界状态。波前马赫数低于临界值或左行运动激波强度高于临界值时，左行运动激波后为倒流、波后总压高于波前。

Abstract:

In order to analyze the flow characteristics in pipe dominated by leftward moving shock， the propagation and evolution characteristics of the leftward moving shock， and the flow characteristics of leftward moving shock/boundary layer interactions in a straight pipe under subsonic conditions were studied with unsteady numerical simulation in this paper. The results indicate that continuous leftward moving shocks are generated in the pipe under periodic pressure perturbation at outlet. The propagation characteristics of the leftward moving shocks are similar， and the attenuation law of intensity and propagation velocity of moving shock presents power function. The total pressure， total temperature and static pressure rise suddenly passing through the moving shock， and then drop gradually under the disturbances of downstream expansion wave. The airfoil recirculation region that induced by leftward moving shock/boundary layer interaction decreases gradually with the leftward moving shock weakens. The theoretical and numerical analyses indicate that there are two critical states： the flow velocity behind the leftward moving shock is zero and the total pressure of flow on both sides of the leftward moving shock are equal. When the Mach number of the flow before the moving shock is lower than the critical value or the leftward moving shock intensity is higher than the critical value， the reversed flow occurs downstream of the moving shock， and the total pressure of the flow behind the moving shock are higher than that before the moving shock.