低レイノルズ数領域において背景圧力がノズル効率に及ぼす効果

抄録

Today, the need for micropropulsion systems for micro- and nanospacecraft is growing. Micro-nozzles generally lead to low Reynolds numbers nozzle flow. It has been reported that nozzle efficiency was decreased at low Reynolds numbers region. However, there were gaps of nozzle efficiencies at same Reynolds number in previous researches, and ambient pressure was suggested as one possible cause of the gaps. In this study, nozzle performance was measured by changing the ambient pressure at throat Reynolds number ranged from 50 to 800. As a result, it was shown that low ambient pressure leads high nozzle efficiency only at throat Reynolds numbers under 200. It suggested that nozzle efficiency was affected by both throat Reynolds numbers and ambient pressure.