关键词: 液体火箭发动机;单组元推进剂;低温;试验研究;起活时间

Abstract: In order to explore the working characteristics of the mono-propellant 300N engine in the low temperature environment and to reveal the main influencing factors， the low temperature environment experiments simulating flight environment were carried out taking the mono-propellant 300N engine as the experimental object. The research methods of low temperature experiments of 300N engine were given. The results of low temperature experiment were summarized from the effect of temperature difference on engine performance， catalyst activity difference on engine starting characteristics and low temperature on electromagnetic valve response characteristics. The results show that low temperature is the main factor on the performance of the 300N engine， the catalyst at -48°C cannot complete the catalytic decomposition of the propellant， and the engine works abnormally. The activation time at -30°C is 80.5~87.5ms， the engine can start normally， and there is an exponential relationship between starting temperature and activation time. The difference of catalyst batches also has a certain impact on the low-temperature performance of the engine. The activation time between different batches of catalysts can vary up to 91ms at low temperature. During the low temperature test， the closing time of the electromagnetic valve was affected by the viscosity of the low temperature propellant and the back pressure， resulting in obvious hysteresis. The delay time of control was about 100ms， which had a certain impact on the precise control of the engine.

Key words: Liquid rocket engine;Mono-propellant;Low temperature;Experiment;Activation time