单组元推力器毛细管两相流影响分析

Study of Two-phase Flow in Injector Tube of Monopropellant Thruster

单组元推力器在工作过程中产生的高温向毛细管处传递,使毛细管内产生气液两相流动。随着推进剂流量的减小,气相组分将不断增加,并会产生明显的气阻。文章就气阻对推力器的影响进行了专题研究,采用FLUENT软件,基于体积分数模型和多相流控制方程,对84种条件下毛细管内两相流的分布情况和两相流对推力器毛细管压差的影响情况进行了数值模拟,并通过两种推力器热试车开展了毛细管内两相流对推力器燃压影响的专项试验。数值模拟结果和试验结果表明,在毛细管内径足够小时,毛细管内的两相流引起的气阻均会导致毛细管内部压降的突然变化,从而引起推力器燃压阶跃,燃压逐渐降低,并进一步影响推力,使推力逐渐下降。

During the application of satellite propulsion systems, the high temperature raised in the process of monopropellant thruster is transferred to the injector tube, leading to the two-phase flow phenomenon. As the massflow of propellant decreases, the pneumatic resistance will increase accordingly. By using the FLUENT software, the influence of pneumatic resistance on the thruster performance was studied. Based on the proportion fraction model and government equations of multiphase flow, the flow and pressure distribution in the injector tube under 84 operating conditions were presented. Furthermore, special tests on multiphase flow-combustion pressure relationship were also performed. Experimental and numerical results show that the pneumatic resistance can result in the sudden variety of pressure drop when the inner diameter of injector tube is small enough, and which cause the decreased thrust ultimately.