凝胶推进剂雾化特性研究进展

Research Progress on Spray Characteristics of Gelled Propellants

关键词:  凝胶推进剂  火箭发动机  雾化特性  液膜  撞击流

Key words:  Gelled propellant  Rocket engine  Spray characteristic  Liquid sheet  Impinging jets

摘要:

为了进一步认识凝胶推进剂雾化过程，促进凝胶发动机的设计和优化，综述了射流撞击式、离心式、气泡式以及燃烧条件下凝胶推进剂雾化特性的研究进展。综述结果表明，凝胶推进剂雾化性能明显差于牛顿流体推进剂，凝胶液膜尺寸显著增大，液丝较难破碎为小粒径液滴；射流撞击式喷嘴对凝胶推进剂的雾化效果优于离心式喷嘴；随着射流雷诺数和韦伯数增大，撞击式凝胶液膜的雾化模式依次为边缘闭合模式、边缘开放模式、无边缘射线模式、液丝分离模式和充分发展模式；采用锥形结构、减小喷嘴出口长径比、方形和椭圆形喷嘴出口皆有利于凝胶液膜破裂，且增大喷注压力、撞击角、温度、室压和减小撞击距离均能改善液膜雾化效果。燃烧条件下MMH/NTO凝胶推进剂撞击液膜破裂雾化机制在宏观上与冷模条件下凝胶推进剂模拟液撞击液膜较好地吻合。此外，对凝胶推进剂雾化特性的进一步研究工作提出了建议。

Abstract:

To further understand the spray process of gelled propellants and promote the design and optimization of the gelled engine， the research progresses on the atomization characteristics of gelled propellants from impinging jets， swirl， bubble injectors and under combustion condition are reviewed. The review results show that， the atomization performance of gelled propellants is significantly worse than that of Newtonian fluid propellant. The size of the gelled sheet increases obviously， and the ligament is difficult to break into small droplets. The spray quality of impinging jets injector on gelled propellants is better than that of swirl injector. As the jet Reynolds number and Weber number increase， the spray patterns of gelled impinging sheets display the closed rim， open rim， rimless ray， ligament separation and fully developed patterns in turns. The uses of the conical structure， decreasing the ratio of the length to diameter at nozzle exit， square and elliptic nozzle exit are all beneficial to the breakup of gelled sheets， and increasing the injection pressure， impinging angle， temperature and chamber pressure， as well as reducing the impinging distance can also improve the spray quality of gelled sheets. The breakup and spray regimes of MMH/NTO gelled propellants impinging sheet under combustion condition macroscopically agree with those of gelled propellant simulants under cold model. In addition， suggestions for further researches on the spray characteristics of gelled propellants are put forward.