Effect of Loading Densities in Closed Vessel Tests on the Burning Rate of a Propelling Charge.

Closed vessel firing of gun propellant at different loading densities is conducted for evaluation of its ballistic parameters. Although in actual gun applications, loading densities are higher, but for closed vessel evaluation standard loading density is taken as 0.2 g/cc for interior ballistic calculations of guns. Closed vessel evaluation of standard triple-base propellant in hepta-tubular configuration with loading density varying in the range of 0.2 g/cc to 0.3 g/cc is conducted for the evaluation of salient ballistic parameters. It is observed that maximum pressure increases with increase in loading density of propellants. As loading density increases, rate of rise of pressure also increases. Accordingly, a rise in burning rate is also observed. However, the burning rate index (α) and coefficient (β) of the power law of burning (r = βP^α) is found independent of loading density. The average values of these burning rate parameters are calculated as (α =) 0.78 and (β =) 0.45 for the studied propellant. [ABSTRACT FROM AUTHOR]