喷管旋涡相互作用的数值研究

Numerical study on vortex-nozzle interactions

本文针对喷管与旋涡相互作用问题,建立了由Taylor涡和Ludwieg管构成的数值模型,采用VAS2D方法模拟了旋涡通过喷管的完整过程,着重考察了不同的旋涡强度下,喷管内流动参数(喷管轴线压力、波系结构等)和旋涡特征参数(旋涡形状、涡心轨迹、涡心迁移速度、旋涡面积等)随时间的演变规律.设计了跟随旋涡移动的网格加密方法,可精细地捕捉旋涡演化的细节.研究结果表明在喷管前部旋涡产生明显的压力扰动;在喉道前后的膨胀区旋涡向外扩散,面积增大但总环量基本维持不变,压力扰动逐步降低.当旋涡较强时,旋涡内部上下位置产生激波,并于涡核处中断.逆时针旋涡接近喉道后,涡心轨迹开始向上壁面偏转,迁移速度受到抑制;旋涡越强,轨迹上抬程度越明显,迁移速度越小.

A numerical configuration consisting of Taylor vortex and Ludwieg tube is established to study the interaction between nozzle flow and vortex. The VAS2D method is used to simulate the complete process of the vortex through the nozzle and a grid refinement method that follows the vortex movement is designed to finely capture the details of the vortex evolution. The flow parameters （nozzle axis pressure, wave system structure, etc.） in the nozzle and vortex characteristic parameters （vortex shape, center trajectory, migration velocity, vortex area, etc.） evolved over time are investigated under different vortex intensities. The results show that the vortex in the front of the nozzle has caused a pressure disturbance in the nozzle flow. In the expansion area before and after the throat, the vortex expands outwards, the area increases but the total circulation remains basically unchanged, and the pressure disturbance gradually decreases. If the vortex is strong enough, two shock waves are generated in the upper and lower positions of the vortex. When the anticlockwise vortex approached the throat, the orbit of the vortex begins to deflect toward the upper wall, and the migration speed is suppressed; the stronger the vortex, the larger deflected distance of the vortex center and the smaller the migration speed.