中文摘要：

采用连续介质方法和直接模拟Monte Carlo（DSMC）方法数值模拟研究了喉部宽度为34μm的二维Laval型微喷管内流场的流动状况.设计了三种不同喉部形状的微喷管：尖角型、圆角型和平角型.计算分析了喉部形状、扩张比等方面对流场结构及推进性能的影响.研究发现,圆角型微喷管的综合性能最优,平角型微喷管具有较大的比冲效率;适当增大扩张比能提高微喷管的性能.

英文摘要：

Characteristics of flow field in Laval micronozzles with 34 μm throat-width were studied numerically by using continuum and direct simulation Monte Carlo（DSMC） method.Three types of micronozzles with different throat shapes were designed,such as：sharp-corner,smooth-corner and flat-corner.Based on the geometric structure design,effects of throat shape and expansion ratio on flow field and propulsion performance were analyzed,respectively.It is discovered from the results that,the comprehensive propulsion performance of the micronozzle with smooth-corner throat is the best,while the micronozzle with flat-corner throat has much better specific impulse efficiency.When the expansion ratio becomes larger,both thrust and specific impulse will increase.