中文摘要：

基于连续介质模型模拟研究了喉部宽度为37μm的二维Laval型微喷管内气体流动特性.计算分析了落压比变化对流场结构的影响;研究了前人文献中提到的'超声速环'现象,发现其本质就是过膨胀状态下微喷管内形成的'马赫盘',并利用激波理论分析讨论了在微尺度下该现象的形成机理及产生条件;在出口压力不变的情况下,采用落压比界定出'超声速环'可能存在的范围;讨论了落压比与激波对微喷管总压降的影响.

英文摘要：

Characteristics of gas flow in a 2-D Laval micro-nozzle with 37 μm throat-width were studied through numerical simulation based on continuum theory in this paper.Influences of pressure ratio on the configuration of the flow field were investigated in detail.The formation mechanism and requirement of supersonic annular phenomenon,whose essence is 'Mach disk' formed in micro-nozzle under over-dilation condition,were analyzed in micro-scale by shock wave theory.While the exit pressure remained unchanged,the po...