水分解微推力器脉冲燃烧过程实验研究 *

Experimental Study on Pulse Combustion Process in Micro-Thruster Using Electrolysis ofWater

关键词:  微推进  水分解推力器  氢氧混合气体  定容燃烧

Key words:  Micro propulsion system  Water electrolysis propulsion  Hydrogen-oxygen mixture  Constant-volume combustion

摘要:

水分解推进系统是一种特别适用于微小卫星应用需求的技术方案，其性能与推力器燃烧过程和工作时序的匹配密切相关。为了优化设计、提高性能，使用快速响应的压力传感器对水分解推力器燃烧室内的定容预混燃烧过程进行了测量。典型信号显示，典型燃烧过程包括缓燃、爆燃及爆燃波反射、未烧完气体缓燃、燃气冷却及吸附等五个阶段。在氢氧混合气体的初始压力从30kPa逐渐升高到90kPa时，爆燃导致的压力最大值出现的时间从355μs缩短到172.5μs，爆燃强度逐渐增大，缓燃完成的时间基本不变，缓燃导致的最大压力逐渐增大，但是明显低于绝热定容燃烧，燃烧过程受散热和表面吸附的影响显著。燃烧和冷却的特征时间均为毫秒量级，推力器的排气时间精度应优于亚毫秒量级，以保证工作时序与燃烧及冷却吸附过程相匹配。

Abstract:

Micro-propulsion system using electrolysis of water is a promising option for microsatellites，and the matching of operation timing sequence and combustion process in thruster plays a key role in its performance. To optimize design and improve performance，a blast pressure sensor was employed to determine the combustion process of stoichiometric mixture of hydrogen and oxygen in the chamber. According to typical experimental results，the combustion process includes laminar combustion，deflagration，reflection of deflagration wave，laminar combustion of residue fuel，cooling and adsorption. As the initial pressure of gas mixture gradually increased from 30kPa to 90kPa，the time required for complete deflagration decreased from 355μs to 172.5μs，the intensity of the deflagration increased，while the time required for completing the combustion process did not show obvious difference. Pressure increment caused by deflagration is far below which caused by adiabatic combustion，which indicates the cooling and adsorption process obviously infect the combustion process. The combustion time and cooling time are both in millisecond level. To optimize the thruster performance，the accuracy of operation timing sequence should be better than 1 millisecond.