Simulation And Experiment Research On The High Efficient Combustion Chamber For Space Orbit Maneuvering Rocket Engine

With the increase of the new generation’s capacity and life, higher performance of the orbit control engine is required. Optimum design of the injector, combustion chamber and nozzle are the three aspects to improve the engine’s performance. The low combustion efficiency of liquid film has become the main factor which cause the specific impulse loss, meanwhile, the improvement of the combustion temperature brings out the higher demand for high temperature materials, and high efficient combustion chamber technology has become the bottle neck in the development of high performance orbit control engine.The key technologies of high efficient combustion chamber are liquid film cooling, combustion chamber construction and high temperature material. Reasonable design of liquid film cooling can assure to meet the requirement of material and satellite. Optimum design of combustion chamber construction can improve the reaction of liquid film and decrease the performance loss of the engine. The ability to withstand high temperatures of the material determines the combustion temperature level and is the basic requirement for optimum design of liquid film cooling and combustion chamber. Materials of high strength, good oxidation resistance and excellent erosion protection at higher temperature should be achieved.Focused on the three key technologies, the high efficient combustion chamber was studied by experiment and numerical simulation. The paper is divided into seven chapters, and the main content of every chapter is presented as follow. Focused on liquid film cooling design, the film formed by free injection on wall surface is studied by experiment and numerical simulation. The effects of nozzle pressure drop, nozzle diameter, incident angle and surface curvature radius on film flow and film thickness are analyzed.The combustion and heat transfer simulations of engines with cylindric chamber, stepped chamber and secondary combustion chamber in rating condition are conducted with the same models. The results indicate higher combustion efficiency may achieve with longer chamber, but the engine temperature rises too. With reasonable characteristical length of the chamber, the engine temperature may drop off by liquid film with different incident angle. With stepped chamber, the mixing of fuel and main gas is not enchanced and the combustion efficiency is not higher than those of cylindric chamber. With secondary combustion chamber, the entraining of the liquid film to central gas helps the fuel evaporation, mixing and combustion, so higher performance and temperature are achieved, while the high temperature of the disturb ring and chamber wall is not useful for long life of the engine. If the material’s ability to resist high temperature is not high enough, engines with cylindrical combustion chamber is a better choice.Engines with cylindrical chamber, stepped chamber and secondary combustion chamber are tested by hot fire test, the results indicate that high performance and low temperature engine may achieved by increasing the chamber length and optimizing the cooling film design. With stepped chamber or secondary combustion chamber, the engine’s combustion efficiency may be improved, but the material can hardly stand the high temperature. The consistant between tests and simulation verifies the VOF model for liquid film simulation.High temperature material research is conducted, including CVD Ir/Re, Ta10 W coat and C/Si C composite material. Several combustion chambers are made up with those materials and tested by hot fire testing. The results indicate that CVD Ir/Re and C/Si C composite material can not meet the requirement of engineering applications. The working life of Ir/Re is above 300 s, but the protection technology of Ir in low temperature should be solved first. As to the composite material, the matrices of composite material and high temperature oxidization should be improved. The coat of Ta10 W alloy has passed the 3600 s hot fire testing, the thermal shock resistance and working life should be improved for practical applications.Based on the simulation and test study, the design rule of high efficient combustion chamber was established and the full size space orbit control engine was designed. The chamber with longer characteristical length and two incident-angle jet cooling is made of T10 W alloy, the maximum temperature of the engine is about 1600 ℃, the specific impulse is 323.6 s, the during time is above 3600 s and the feasibility of high efficient combustion chamber technology was verified.