Effect of chemical reactions on the fluidic thrust vectoring of an axisymmetric nozzle

During the last years, several thrust control systems of aerospace rocket engines have been developed. The fluidic thrust vectoring is one of them; it is simple in design and offers a substantial gain in weight and in performance. Most of studies related to this device were carried out with cold gas. It’s quite legitimate to expect that the thermophysical properties of the gases may affect considerably the flow behavior. Besides, the effects of reacting gases at high temperatures, under their effects all flow parameters like to vary. This study aims to develop a new methodology that allows studying and analyzing the fluidic thrust vectoring for a perfect gas, by taking into account the effects chemical reactions on the flow parameters, such as separation point, reattachment point downstream and pressure distribution upstream the injection port. In this study, the thrust vectorization implying frozen reacting hot gases was carried out by considering a chemical reaction mechanism. The thermodynamic parameters of the flow are calculated within the combustion chamber and different sections of the supersonic part of the nozzle. The results show a good agreement for cold gas, and as expected à slight difference for hot reacting gases. Performance analysis are conducted and basic conclusions are drawn in terms of thermodynamic gas properties effect on the fluidic thrust vector system. The primary effect was related to the gas molecular weight and its specific heat ratio. It is observed that for fixed injection conditions, the vectoring angle is different when the injected gas molecular weight and specific heat ratio are different. For a given mission of the launcher, it can be concluded that the mass of the embedded gas, used for the fluidic vectorization system, can be significantly reduced, depending on its molecular weight and specific heat ratio.