激波/泄漏涡相互干扰对跨声压气机流动稳定性的影响

对单级跨声压气机Stage 35进行了单通道全三维定常数值模拟,开展了网格密度对计算结果影响的研究,从而确定了一套最佳网格配置,该套网格配置预测的总性能和基元性能与试验结果符合得最好.以此为基础对Stage 35的内部流场进行分析,发现其流动失稳最有可能是由动叶近叶顶靠近压力面侧的低能堵塞团引发的.随着流量的减小,间隙泄漏涡的强度和旋拧度随着叶片载荷的增加而增加,激波与泄漏涡相互干扰使得近失速条件下间隙泄漏涡破碎,涡破碎极有可能是动叶近叶顶靠近压力面侧低能流体产生的主要原因. 

Influence of shock/tip leakage vortex interaction on flow stability in a single-stage transonic axial compressor

Three-dimensional numerical simulations were conducted to analyze the flow field in a single-stage transonic compressor Stage35. First, three kinds of gridding were modeled to investigate their prediction accuracy on overall performance and blade-element curves. The criterion for choosing the optimum gridding was that its prediction matched best with the experimental data. Then, the internal flow filed of the optimum gridding was analyzed to find out the most probable factor influencing the flow stability, and it is found that low-energy fluid near pressure surface at rotor tip most likely induced flow instability. As the mass flow rate reduces, the intensity and swirl ratio of the tip leakage vortex (TLV) increase with the blade loading. The breakdown of the TLV happens due to the interaction of shock/TLV at the near-stall condition, thus mainly leading to low-energy fluid accumulating near the pressure side of rotor tip passage.