微型涡喷发动机离心压气机的性能计算及分析

Performance calculation and analysis of a micro-turbojet centrifugal compressor

文中对微型涡喷发动机的离心压气机进行了气动分析。采用商业仿真软件NUMECA对某微型涡喷发动机的离心压气机进行70%、80%、90%、100%转速的数值计算及流场分析。计算结果显示:不同转速下随着流量的减小,效率先增大后减小,压比逐渐增大。通过对流场分析得出:100%转速时,压气机的损失主要来源是叶轮主流叶片前缘的激波、叶轮叶顶吸力面附近的流动分离与堵塞、轴向扩压器前的轮毂侧和叶背的分离;对比其他转速,由于压气机前后级间存在匹配关系的变化,在离心压气机各部件流场恶劣趋势不同的情况下,90%转速相对于其他转速的流场损失较小,因此其效率更高。

In this paper,the aerodynamic results of a centrifugal compressor applied to a micro-turbojet engine are analyzed.The commercial software NUMECA is used to carry out the numerical calculation and flow field analysis of the centrifugal compressor of a micro-turbojet engine at 70%,80%,90% and 100% speed.The calculation results show that with the decrease of flow rate at different speeds,the efficiency first increases and then decreases,and the pressure ratio increases gradually.Through the analysis of the convective flow field,it is concluded that at 100% speed,the main sources of compressor losses are the shock wave at the leading edge of the impeller mainstream blades,the flow separation and blockage near the suction surface of the impeller tip,and the separation of the hub side before the axial diffuser and the axial diffuser blade back.Compared with other speeds,due to the change in the matching relationship between the front and rear stages of the compressor,under the condition that the flow field of each component of the centrifugal compressor has different trends,the flow field loss at 90% speed relative to other speeds is smaller,so the efficiency is higher at 90% speed.