The Thermal Analysis In Tail-pipe Nozzle Of A SRM

Tail-pipe nozzle is one of the key components of the solid rocket motor, it runs at terrible condition with high pressure, high speed and high temperature. In the work, the high temperature gas delivering large amounts of heat to nozzle shell, seriously affecting the nozzle structural strength, the increase of nozzle shell temperature will affect the normal work of nozzle external electronic device, at the same time, the heat loss will affect the overall performance of solid rocket motor. On the other hand, with the development of solid propellant technology, a high-energy propellant which is added metal powder has been widely used, but the metal powder combustion will produce a large amount of solid or liquid particles, which makes a complex two-phase flow in the nozzle. The particle existence makes the heat transfer conditions worse, so it is necessary to analyze details about heat transfer and gas particle two-phase flow.About this research, the main contents can be listed as follows:A model of nozzle thermal protection was presented, the model of this flow field was simulation calculated and analyzed by using the software of FLUENT, then combining the method of numerical simulation and engineering calculation to design the tail pipe nozzle thermal protection layer. The method of combining numerical simulation and engineering calculation has more advantages than the traditional method to design the tail pipe nozzle thermal protection layer;The simulation calculation of pure gas phase is exerted to the overall model of nozzle thermal protection, and it verify the reliability of the design method. The results show that the throat section and contraction section are the most serious areas in temperature field. These places are where we should give more attention in the thermal protection layer;The two-phase flow field of the tail pipe nozzle is calculated with the Eulerian model. Simulated result indicated that the Mach number will be lower and the temperature will be higher with the increase of particle concentration and the decrease of particle diameter. The influence will be greater on nozzle throat and expansion period.Simulation calculation is exerted to the overall model of nozzle thermal protection. The results show that the temperature of nozzle thermal protection is higher when the particle phase is added. Especially in the throat and expansion period, the temperature has affected the normal work of the nozzle. So the particle phase is not to be ignored when design the nozzle thermal protection.