As the development of space technology and the increasing of environment protection requirement, it is an inevitable trend for the green propellant to be used in the space system in the future. The propellant combinations of hydrogen peroxide and kerosene have many advantages, but they are rarely applied in the practical rocket engine in our country. So the low-thrust H2O2/kerosene rocket engine is investigated and is found that the injector plays a key part role. In this thesis, gas-gas coaxial swirl injectors, gas-liquid coaxial swirl injectors and gas-liquid coaxial jet injector are designed and tested aiming at different state kerosene. Besides, the numerical simulations are performed with CFD code to analyze the mixing and combustion characteristics of the H2O2/kerosene propellants in the chamber for the above three different injectors. The numerical results were compared with the experimental results. Based on the design theory of injectors, gas-gas coaxial swirl injectors are designed for the supercritical kerosene because it can be assumed as gas. Gas-liquid coaxial swirl injectors and gas-liquid coaxial jet injectors are designed for cold kerosene. H2O2 is injected tangentially through the outer tube while the kerosene is injected through the inner tube for the coaxial swirl injectors. The experimental and simulated results of the gas-gas coaxial swirl injectors indicate that the injector panels endure greater heat flux and the temperature is 300~400℃ higher than that of the gas-liquid coaxial swirl injectors. As a result, the swirl intensity or swirl flow of H2O2 must be reduced in order to avoid the ablation of the gas-gas coaxial swirl injector panels. The experimental and simulated results of the gas-liquid coaxial swirl injectors show that no ablation occurs in the injector panels and the key parameters such as pressures or thrusts can meet design requirements well. The designed gas-liquid coaxial swirl injectors are more proficient than the gas-gas coaxial swirl injectors. We also found that the greater the swirl intensity, the closer the flame from the injector panels, and the higher the temperature of the panels. On the contrary, the smaller the swirl intensity, the longer the combustion chamber, and this do not meet the weight reduction requirement. In conclusion, the b3 (A=3) injector may perform best among the gas-liquid coaxial swirl injectors, in order to meet the requirement of the weight deduction. Simulated results of the gas-liquid coaxial jet injectors show that there are three factors that influence the combustion length, including the thickness of the inner nozzle which is most important, the indentation of the inner nozzle and the pressure drop of the outer nozzle which are lesser factors. Also, it is carried out that the combustion length of these injectors (30-50mm) is much longer than that of gas-liquid coaxial swirl injectors (5-15mm). So the longer combustion chamber is needed. Generally, the gas-liquid coaxial swirl injectors are better than the jet injectors.
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