中文摘要：

针对国际标准规定的几何形状下微小尺寸音速喷嘴加工的困难，探讨应用MEMS技术加工的方形截面喷嘴进行微小流量测试的可能性，重点考察几何形状的差异所造成喷嘴流动特性的改变和相关测试技术的特性。论文具体对微米、毫米量级不同截面形状喷嘴内流场进行系统的数值模拟计算，发现方形截面微小喷嘴流出系数明显小于对应圆形截面，主要原因在于方形截面微小喷嘴喉部流动特性的差异，即喉部截面内只能是小范围能达到当地声速，而不是圆形截面喷嘴喉部界面大部分区域能达到声速，从而使其流出系数较后者明显减小。

英文摘要：

The flow characteristics in mini/micro rectangular cross-section nozzles manufactured using MEMS technology was studied in this paper. The fluid flow was different greatly from that in circular nozzles with identical cross-section area, and the discharge coefficients of mini/micro rectangular nozzles are much smaller than that of the equivalent circular ones. The Mach number can only reach 1 at throat cross-section of mini/micro rectangular nozzles, while in most zone for circular nozzles. This can be the most important reason for the significantly decrease of the discharge coefficient.