丁英涛, 姚朝晖, 何枫. 微喷管内气体流动特性研究[J]. 工程力学, 2004, 21(3): 190-195.
引用本文: 丁英涛, 姚朝晖, 何枫. 微喷管内气体流动特性研究[J]. 工程力学, 2004, 21(3): 190-195.
DING Ying-tao, YAO Zhao-hui, HE Feng. GAS FLOW CHARACTERISTICS IN MICRO-NOZZLE[J]. Engineering Mechanics, 2004, 21(3): 190-195.
Citation: DING Ying-tao, YAO Zhao-hui, HE Feng. GAS FLOW CHARACTERISTICS IN MICRO-NOZZLE[J]. Engineering Mechanics, 2004, 21(3): 190-195.

微喷管内气体流动特性研究

GAS FLOW CHARACTERISTICS IN MICRO-NOZZLE

  • 摘要: 研究旨在提高微型空间推进器和微型气体涡轮机等微器件的性能.采用硅微加工技术在硅片上制作出矩形截面三维收缩-扩张微喷管,喉部宽度为16?,深度为20?,收缩比为1.25:1.实验测量了不同进出口压比条件下微喷管内氮气流量特性.实验设定进出口压比范围为1.0~5.0,由此出口体积流量范围为0~0.2mL/s,出口截面特征雷诺数小于500.基于两种数值模拟方法(有限体积法和Boltzmann气体动力学方法)对微喷管内部流动特性进行了数值模拟.数值模拟结果与实验结果相吻合.数值模拟结果发现几点不同于宏观流动的异常现象:随着压比的提高,声速截面逐渐偏离喉部,向下游区移动,并且下游区的流动不断加速.当压比达到5.0时,出口截面中心区域的马赫数达到1.2.沿程压力分布呈现非线性下降的趋势.这些现象主要是由于相比于常规尺度管道,微小尺度下表面效应引起的粘性附面层效应和三维效应更显著.

     

    Abstract: This research is aimed at improving the performance of micro-space propulsions and micro-gas turbine generators. Based on the micro-fabrication technology, 3D rectangular cross section micro-convergent-divergent-nozzle was fabricated in silicon wafer. Its width in the throat was 16?, the depth was 20? and the contraction ratio was 1.625:1. For different inlet/outlet pressure ratio, the volume flow rate characteristics of nitrogen were measured experimentally. The pressure ratio ranged from 1.0 to 5.0, outlet volume flow rate ranged from 0 to 0.2mL/s and outlet Reynolds number was lower than 500. The gas flow characteristics were analyzed by two numerical simulation methods (finite volume method and Boltzmann Gas Kinetic method). Good agreement between computational results and experimental data was found. The simulation results indicate that the sonic cross section gradually moves to downstream of the throat with the increase of pressure ratio. The flow is accelerated in the downstream of the throat. A Mach number is up to 1.26 near the outlet center cross-section when the pressure ratio is 5.0. The pressure distribution is non-linear. It demonstrates that viscous boundary layer and 3D effects are more predominant in micro-nozzle than those in macro-nozzle.

     

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