Abstract: The first and second generation 490N bipropellant apogee engine uses nitrogen tetroxide oxidizer and monomethydrazine fuels,which are radiations and fuel-film cooled thrusters with impinging unlike doublets.By now,more than eighty engines have been hot fire tested,and the results show that the specific impulse varies as a quadratic function of propellant temperature.And the second generation 490N engine hot fire tests also show the same relation.This paper summarizes the results of theory and experiment research on propellant temperature effect of specific impulse.

Key words: Liquid apogee engine;Specific impulse;Propellant temperature

摘要： 用于卫星变轨的第一、二代液体双组元490N发动机均采用了四氧化二氮(N2O4)/甲基肼(MMH)推进剂组合,直流互击式喷嘴以及液膜辐射冷却身部。迄今为止,第一代490N发动机共进行了80多台次的高空热试车。统计结果表明:真空比冲与推进剂温度存在负二次方的关联关系;另外,第二代490N发动机的多台热试车结果也表明两者有一定的联系,就此进行了理论分析与试验研究,阐述了其中的关联关系。

关键词: 远地点发动机;真空比冲;推进剂温度