Research on coupled heat transfer of film cooling in LOX/GH2 thrust chambers

To better understand the performance of gaseous film cooling near the injector region in the LOX/GH 2 thrust chambers, a methodology is employed to simulate the coupled heat transfer of the film cooling in thrust chambers with regenerative cooling.The conjugated flow and heat transfer behaviors of film coolant, hot gas, cooling channels and regenerative coolant are numerically investigated.A three-dimensional non-adiabatic flamelet model using real gas equation of state is developed to solve the combustion and validated against the experimental data.Film cooling performance is predicted for the conditions with different geometrical parameters and mass flow rates of the film coolant.The result shows that the reverse flow zones are formed and developed in the region near the injectors The occurrence of those zones is responsible for the significant reduction of the hot-gas-side wall temperature near the head plate of the injector.The coolant mass flow rate has a great influence on the film cooling performance due to the variety of coolant momentum in the exit of orifices and vorticity in the near-injector region.An optimum mass flow rate for maximizing the averaged effectiveness exists for a given film orifice geometric configuration.The high averaged effectiveness and the uniform flux distribution of hot-gas-side wall are observed at small orifices spacing.The film cooling effectiveness in the orifice exit region is obviously enhanced when the diameter of the orifice increased in the front part of the combustion chamber.The results would be useful for the analysis and optimization design of the straight cylindrical coolant orifices in the LOX/GH 2 thrust chamber.