微喷管数值模拟

本文数值模拟喉部半高为34μm的二维微喷管,分别分析了固定进口及固定喉部尺度下扩张角、扩张比以及滑移边界条件对微喷管性能的影响,发现最佳半扩张角在20°-22°之间,而最佳扩张比为7。为了比较壁面滑移条件对计算结果影响,分别数值模拟了喉部尺寸为68μm和6.8μm的微喷管,发现Kn<0.001时,滑移边界条件对数值模拟结果较小;而0.002

NUMERICAL STUDY ON MICRONOZZLES

The effects of half expansion angle, expansion ratio and boundary conditions on performance of 2D micronozzle with half throat heitht 34 were numerically studied. To keep micronozzle work effectively, the best half expansion angle ranges from 20 to 22 degrees, while best expansion ration is 7. To study effect of boundary conditions on numerical results, two micronozzles with half throat height 68 and 6.8 were simulated using N-S equations, with no-slip and slip boundary condition. It was found when Knudsen number is smaller than 0.001, no need to consider slip boundary condition. However, when Knudsen is between 0.002 and 0.045, the slip boundary condition should be applied to study flow field and performance of micro-nozzles.