Lee Kyun Ho
Department of Aerospace Engineering, Sejong University, Seoul, Republic of Korea.
PLoS One. 2017 Jun 21;12(6):e0179351. doi: 10.1371/journal.pone.0179351. eCollection 2017.
A space propulsion system is important for the normal mission operations of a spacecraft by adjusting its attitude and maneuver. Generally, a mono- and a bipropellant thruster have been mainly used for low thrust liquid rocket engines. But as the plume gas expelled from these small thrusters diffuses freely in a vacuum space along all directions, unwanted effects due to the plume collision onto the spacecraft surfaces can dramatically cause a deterioration of the function and performance of a spacecraft. Thus, aim of the present study is to investigate and compare the major differences of the plume gas impingement effects quantitatively between the small mono- and bipropellant thrusters using the computational fluid dynamics (CFD). For an efficiency of the numerical calculations, the whole calculation domain is divided into two different flow regimes depending on the flow characteristics, and then Navier-Stokes equations and parallelized Direct Simulation Monte Carlo (DSMC) method are adopted for each flow regime. From the present analysis, thermal and mass influences of the plume gas impingements on the spacecraft were analyzed for the mono- and the bipropellant thrusters. As a result, it is concluded that a careful understanding on the plume impingement effects depending on the chemical characteristics of different propellants are necessary for the efficient design of the spacecraft.
空间推进系统对于航天器通过调整其姿态和机动进行正常任务操作至关重要。一般来说，单组元和双组元推进器主要用于低推力液体火箭发动机。但是，由于这些小型推进器喷出的羽流气体在真空空间中沿各个方向自由扩散，羽流碰撞到航天器表面产生的不良影响会极大地导致航天器功能和性能的恶化。因此，本研究的目的是使用计算流体动力学（CFD）定量研究和比较小型单组元和双组元推进器之间羽流气体冲击效应的主要差异。为了提高数值计算的效率，根据流动特性将整个计算域划分为两种不同的流动状态，然后针对每种流动状态采用纳维 - 斯托克斯方程和并行化直接模拟蒙特卡罗（DSMC）方法。通过本分析，研究了单组元和双组元推进器羽流气体冲击对航天器的热和质量影响。结果表明，为了航天器的高效设计，有必要仔细了解取决于不同推进剂化学特性的羽流冲击效应。
