Numerical simulation of pintle thruster combustion and heat transfer for MMH/NTO hypergolic bipropellant

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.