Numerical Simulation Investigations Of Combustion And Heat Transfer Of Dual-Operation LOX/Hydrogen Engine

An integrated physical model and numerical method are developed to simulate the spray combustion and heat transfer of liquid rocket engine. Three-dimension full N-S equations and two-phase flow model, which consideres the liquid fuel spray as discrete particles, are employed to describe the combustion processes in the liquid engine. The mass and energy transfer between the two phases are calculated by the droplet evaporation model, and the Arrehnius model is used to obtain the gas chemical reaction rate. The distribution of temperature and heat flux on the wall is obtained by coupling the calculation of heat transfer between the burning gas, chamber wall and coolant water. The spray two-phase model is verifid by comparing the computational result of atomization and penetration of spray droplets in supersonic cold flow with the experimental result.The spray combustion flow and heat transfer progresses of dual-operation LOX/Hydrogen engine are simulated with the models and method founded in this paper. To reduce computing time, a global reaction model , which is verified with eight-step reaction model to obtain the reasonable result in this paper, is used. After the details of flow fields and combustion efficiency and heat flux of dual operations of coaxial swirl injector are compared, it is found that the distribution of produces of oxygen-rich operation or fuel-rich operation is considerable nonuniform, the tempture and heat flux in the wall of fuel-rich operation is obviously decreased. The effect of different injections on combustion efficiency and heat transfer are analysed. The results show that the mixture and combustion efficiency of coaxial swirl injector are better than that of coaxial shear injector, while the temperature and heat flux in the wall is reduced with shear injector. The effect of injectors array on combustion flow and heat transfer is analysed with axial symmetry model. The results show that the injectors array has complex effects on combustion efficiency and heat transfer of rich-oxygen operation and rich-fuel operation.