Transient Combustion in Solid Propellant Cracks.

A one-dimensional theoretical model, incorporating the Noble-Abel dense gas law, has been developed to describe the transient model combustion phenomena inside a propellant crack. The theoretical model can be used to predict wave phenomena, heat transfer from the gas to the propellant surface and associated thermal penetration, flame propagation, and resultant pressurization at various locations along the propellant cavity. Calculations made with the current theoretical model revealed that the internal pressurization rate, pressure gradient, and flame velocity in propellant cracks (for which gases can penetrate) decrease as: the gap width increases, the rocket chamber pressurization rate decreases, and the propellant gasification temperature increases. Additionally, the predicted flame spreading was found to decelerate in a region near the crack tip; this phenomena has been experimentally observed by others.