结构参数对单组元高室压脉冲推力器的性能影响

高室压脉冲火箭发动机由于使用差动式可移动喷注器,能够得到比供给压强高得多的燃烧室压强.为了分析其工作特性,建立了单组元脉冲火箭发动机挤压喷注、燃烧、排气过程的集总参数模型,以硝酸羟铵(HAN)基作为单组元推进剂,采用四阶龙格-库塔法对模型进行求解.分别从喷注器喷孔面积、喷注器差动面积比、喷管喉部面积、喷注器行程等方面分析并总结了结构参数对单组元高室压脉冲发动机性能的影响规律及影响程度.结果表明:计算模型能反映发动机的实际工作过程,其中,喷注器行程对燃烧室平均压强和平均比冲的影响最大,平均推力则对喷管喉部面积的变化最为敏感,上述两个结构参数是发动机优化设计时的首要考虑因素;其他结构参数对发动机也存在不同程度的影响,可以作为次要因素来考虑. 

Influence of structural parameters on performance of monopropellant pulse thruster with high chamber pressure

Due to the movable injector which can be regarded as a differential piston with some spray holes,the pulse thruster can provide much higher chamber pressure than the supply pressure of propellant.In order to analyze the operating characteristics of this type of pulse thruster adopting the monopropellant of HAN(hydroxylammonium nitrate),a lumped parameter model was established and the fourth-order Runge-Kutta method was applied to get its numerical solution which reflected the unique pulsating characteristics.The influence of the structural parameters on the thruster performance such as the area of injection holes,nozzle throat area,displacement and differential area ratio of the movable injector was analyzed and summarized.Though the pulsating operation would come to change when any of the above parameters is altered,the displacement and the nozzle throat area are the most influential and should be optimized firstly in the design progress of the new type of pulse thruster.The average pressure in the combustion chamber and the average specific impulse of the thruster are sensitive to the injector displacement,and the average thrust is sensitive to the nozzle throat area.