针栓喷注式MMH/NTO推力室燃烧及传热数值仿真

Numerical Simulation of Pintle Thruster Combustion and Heat Transfer for MMH/NTO Hypergolic Bipropellant

关键词:  针栓式喷注器  自燃推进剂  液体火箭发动机  燃烧流动与传热  数值仿真

Key words:  Pintle injector  Hypergolic propellant  Liquid rocket engine  Combustion flow and heat transfer  Numerical simulation

摘要:

为了研究针栓喷注器不同压降、动量比和雾化细度对燃烧室流场结构和推力室性能的影响，采用Euler-Lagrange方法对针栓喷注式双组元MMH/NTO自燃推进剂液体火箭发动机进行了燃烧流动与耦合传热数值仿真。燃料液滴喷射的初始条件由VOF方法计算获得，流场计算采用Realizable k-ε湍流模型及11组分4步反应化学动力学模型，流固耦合区域对流换热为耦合换热边界。结果显示，采用VOF方法获得的液滴初始喷射角度与实验值相差1.8%～3.5%；仿真计算室压与热试车结果相差2.73%。仿真研究表明:针栓喷注器的压降对燃烧室流场特性的影响要比动量比的影响更显著；对于内路为燃料外路为氧化剂的针栓喷注器而言，改善燃料路的雾化效果所获得的推力室性能比改善氧化剂路的雾化效果所获得的性能更敏感。

Abstract:

In order to investigate the effects of pintle injector pressure drop，momentum ratio and particle size on combustor flow field structure and thruster performances，numerical simulation of combustion and conjugate heat transfer for a MMH/NTO hypergolic bipropellant pintle engine was performed by Euler-Lagrange method. The initial condition of injecting liquid droplets was obtained by VOF model. Realizable k-ε turbulence model and 4-step with 11 species chemical reaction model were utilized to simulate the flow fields. The heat transfer of Fluid-Structure Interaction(FSI)region was conjugate heat transfer boundary. The results show that，there is a difference of 1.8% to 3.5% between initial injecting angle obtained by VOF and test data. The difference of chamber pressure between simulation and test is about 2.73%. As the simulation results shown，the pintle injector’s pressure drop has salient effect on combustor performance than momentum ratio. For the pintle configuration with inner fuel and outer oxidizer，the thruster performance obtained by improving the atomization of fuel is more sensitive than by improving the atomization of oxidizer.