Characteristics of Gas Flow Within a Micro Diffuser/Nozzle Pump

英文摘要: The gas flow characteristics for various shapes of micro diffuser/nozzles have been experimentally investigated. The micro diffuser/nozzles with the lengths of 70 mu m, 90 mu m, 125 mu m and the taper angles of 7 degrees, 10 degrees, 14 degrees are designed and fabricated based on silicon micromachining technology for optimizing and comparing. The flat-wall diffuser/nozzle is 40 mu m x 5 mu m in depth and width. An experimental setup is designed to measure the gas flow rates under controlled temperature and pressure condition. Optimized values for the taper angle and the length of the diffuser/nozzle are experimentally obtained.

无缓冲气COIL扩压器流场数值模拟

以无缓冲气化学氧碘激光器（COIL）实验器件的数据计算得到的混合喷管出口参数平均值作为光腔入口条件，对6种不同构型的扩压器从光腔入口至扩压器出口的流场进行了数值模拟，得出了各流场参数分布；对不同构型扩压器的流场特点、总压恢复性能进行了分析；研究了扩压器出口背压对流场参数的影响。结果表明：对于主流无缓冲气的COIL，等截面扩压器具有较好的压力恢复性能；增大扩压器出口背压可以使扩压器的压力恢复性能提高，然而，较高的背压使激波串向光腔方向移动，从而使光腔流场受到干扰，影响光腔的光束质量。