Computing flow, combustion, heat transfer and thrust in a micro-rocket via hierarchical problem decomposition

This work describes the methodology developed to optimize the design of the combustion chamber, the thrust generating nozzle and the cooling system of a micro-rocket using numerical simulations. The coupling between combustion, subsonic/sonic/supersonic flow transition and heat transfer inside the micro-rocket is analysed using a problem decomposition strategy and state-of-the-art numerical techniques. First, the design of the thrust-generating nozzle is optimized, then, the mixing performances and the combustion efficiency are evaluated, finally, the design of the cooling system is verified calculating the heat transfer from the hot gases to the solid shell and to the cooling fluid. Results show that sub-optimal micro-rocket design alternatives can be easily identified through self-validated numerical analyses. In this way, the number of time consuming and costly experiments required for prototypes qualification in the lab can be reduced, focusing the tests on the limited set of sub-optimal alternatives identified by numerical simulations, thus speeding up the development of new devices.