STUDY OF DEPENDENCE OF BURN RATE PARAMETERS OF GUN PROPELLANT ON PRESSURE AND ITS EFFECT ON PERFORMANCE PREDICTION

Abstract

 Tank gun performance prediction is highly sensitive to the ballistic properties of propellants, particularly how their burn rates respond to changing pressures. Traditional models assume static burn rate parameters, but modern nitramine-based propellants exhibit dynamic combustion behaviour. This study investigates the pressure dependence of burn rate parameters, pressure exponent (α) and burn rate coefficient (β), using closed vessel experiments at loading densities of 0.2, 0.3, and 0.4 g/cc for a nitramine-based propellant. Results reveal that both the parameters evolve dynamically with respect to pressure. A novel pressure-dependent burn rate model, a modified Vieille Law (r = β(P).P^α(P)), is constructed and integrated into a Lumped Parameter Model (LPM) for Internal Ballistics prediction. Application of this model in 120mm tank gun Internal Ballistic simulations has reduced the error range in muzzle velocity (MV) prediction from 2.88%-4.32% to 0.14%-1.14% and reduced the error range in maximum chamber pressure (Pmax) prediction from 32.43%-62.43% to 0.60%-6.63%. These advancements enhance safety by mitigating catastrophic pressure spikes and improve precision for military applications.