卫星姿控发动机高空羽流场工程分析

发展卫星姿控小推力发动机高空羽流场的工程估算方法,计算分析其主要燃气组分的分布特征.采用网格技术将发动机喷管出口截面剖分形成多独立点源,建立了非均匀出口流动条件下的分析模型.与自由分子单一点源模型相比,该模型的计算结果更接近实验值.对MBB 10 N双组元发动机多组分羽流场的研究表明,压强场和内能场的变化较剧烈;不同于轻分子组分,重分子组分主要集中于轴线附近,其密度场呈较强方向性. 

Engineering Analysis on a Satellite Attitude Control Thruster Plume at High Altitudes

An engineering estimation method has been developed to calculate satellite attitude control thruster plumes at high altitudes, and the main exhaust gas species distributions are analyzed numerically. The grid generation technique is introduced to split the thruster nozzle exit section into cells, each of which is considered an independent point source, respectively. Hence, a modified free molecule model suitable for the nozzle exit local conditions is obtained. It consists of four primary formulae for density, mass flux, normal pressure and transitional energy flux, and three formulae for velocity, transitional temperature and internal energy flux. A nitrogen plume exhausted from a axisymmetric nozzle is firstly calculated. Numerical outlet conditions obviously influence upon analysis results for flow variables, especially, dynamic and thermodynamic variables. Then, an MBB 10N bipropellant thruster multi-species plume is investigated numerically. Comparisons are presented between the modified model and experiment, and good agreement is found for density distributions. Moreover, the levels of agreement are superior to those using the original single point source free molecule model. Pressure and internal energy vary more rapidly in the plume. It is unlike light molecule species that heavy molecule species mainly focus along the plume axis and their density distributions show a more dominant direction, i.e. axial direction.