Analyse of acoustic property with complicated grain shape in combustion chamber of solid rocket motor

Analyzing acoustic properties of combustion chamber is important part of acoustic instability of solid rocket motor. In this paper a numerical model about acoustic properties of combustion chamber in solid rocket motor with complicated grain shape has been established. Using small amplitude three-dimensional wave equation and finite-element method, acoustic wave frequency, shape and the response frequency property of perturbed field were obtained in the cavity of finocyl grain with and without submerged nozzle. It shows that acoustic pressure response present in inherent frequency sect when the position of microseism is different, but the amplitude of acoustic pressure response is different, cavity with submerged nozzle is as a damp to first frequency.