Non-linear analysis of solid propellant burning rate behavior

The parametric analysis of the thermal wave model of the non-steady combustion of solid propellants is carried out under a sudden compression. First, to observe non-linear effects, solutions are obtained using a computer under prescribed pressure variations. Then, the effects of rearranging the spatial mesh, additional points, and the time step on numerical solutions are evaluated. Finally, the behavior of the thermal wave combustion model is examined under large heat releases (H) and a dynamic factor (β). The numerical predictions show that (1) the effect of a dynamic factor (β), related to the magnitude of dp/dt, on the peak burning rate increases as the value of β increases. However, unsteady burning rate 'runaway' does not appear and will return asymptotically to ap(n), when β ≥ 10.0. The burning rate 'runaway' is a numerical difficulty, not a solution to the models. (2) At constant β and m, the amplitude of the burning rate increases with increasing H. However, the increase in the burning rate amplitude is stepwise, and there is no apparent intrinsic instability limit. A damped oscillation of burning rate occurs when the value of H is less. However, when H > 1.0, the state of an intrinsically unstable model is composed of repeated, amplitude spikes, i.e. an undamped oscillation occurs. (3) The effect of the time step on the peak burning rate increases as H increases. Copyright (C) 2000 John Wiley and Sons, Ltd.