Modeling, Simulation and Characterization of Complex Shaped Solid Propellant Combustion

A model to simulate propellant combustion in a closed bomb and a method for burn rate measurement are presented. The model incorporates the 2D ICT-Cellular-Combustion-Algorithm which numerically simulates the 2D form function of an arbitrary shaped propellant cross section. With the help of preprocessing algorithms to calculate initial surface and volume and a lumped parameter model, which also takes into account pressure dependent thermochemistry, pressure vs. time curves and the dynamic vivacity can be simulated. The model is then coupled with different optimization algorithms to minimize an objective function for burn rate measurement with either pressure or vivacity data. Four different optimization algorithms are compared in detail using synthetic pressure-time and dynamic vivacity data of a 7 perforated propellant with and without white noise. The testing shows that the so called Nelder-Mead-Downhill-Simplex algorithm with a vivacity based objective function allows the most precise, robust and computationally cost effective burn rate measurement. Experimental results for 7 perforated JA2 propellant from a 306 cm(3) closed bomb are used to determine Vieilles parameters and . The determined values of =0,9520 +/- 0,006319 and =0,1522 +/- 0,007592mm/s are in good agreement with previously reported values of =0.9517 and =0.1467mm/s. With the presented model and burn rate measurement method it is possible to determine the burning rates of solid propellants with a high degree of accuracy.