Numerical simulation of a 3D unsteady two-phase flow in the filling cavity in oxygen of a cryogenic rocket-engine

Abstract

The feeding of the LOX dome of a cryogenic rocket-engine is a decisive stage of the transient engine ignition. However flight conditions are difficult to reproduce by experimental ground tests. The work reported here is part of an ongoing research effort to develop a robust method for prediction and understanding the LOX dome feeding. In the framework of this project, experiments with substition fluids (air and water) are conducted, without mass and energy transfer. This work presented here intends to reproduce these experiments through incompressible two-phase flow CFD simulations, in an industrial geometry equivalent to the experimental mock-up, made up of a feeding piper, a dome and 122 injectors. More precisely, the aim is to compare the numerical results obtained with NEPTUNE CFD code with the experimental results, through the dome pressure and the mass flow rate of water at the outlet. An important work was made to obtain the same inlet conditions in NEPTUNE CFD code as the experimenters, in order to compare the numerical results with the experimental results for the best. The influence of the interfacial momentum transfer modeling and turbulence modeling are also studied here. The turbulence modeling plays no macroscopic or local role on the mass flow rate of water, on the mass of water in dome and on the dome pressure. The drag model has a major impact on our results as well globally as locally, unlike the turbulence modeling. The Simmer-like model is prefered in comparison to the Large Interface called LIM, because it is in better agreement with experimental data. Moreover, it has to be highlighted that the Simmer-like model is very sensitive to its parameter d, the inclusion diameter.