The Optimization of Base Bleed Grain Parameters for Maximum Ballistic Performance

Abstract

Solid propellant Base bleed unit is one of the effective methods to increase the range of artillery projectiles. As far as we search, no published study focuses on the optimal dimensions of the base bleed grain. However, few studies focus on the effect of base bleed grain parameters on its ballistic performance in which each parameter was studied separately. The present optimization study is performed on base bleed grain which performed as longitudinally slotted tubular cylinder. Different case studies have been introduced according to the number of design variables which are: grain outer, inner radius, length, burn rate, base bleed grain unit orifice diameter. Moreover, the study is extended to demonstrate the effect of these parameters on the innovative multi-burn rate base bleed grain. In this new idea, the grain is splitted into two horizontal parts one with higher burn rate than the other part. The idea is to have a grain that provides high mass flow rate in the first seconds of projectile flight, while keeping long bleeding time. The optimization constrains are the upper and lower limits of each design variable. An analytical model has been developed in C++ environment to accurately evaluate the range of the projectile. This model is then utilized in combination with design of experiment (DOE) and the response surface method (RSM) to develop a smooth response function which can be effectively used in the design optimization formulation as the objective function. The objective of the optimization is to find the design variables which contribute the maximum range. Paper: ASAT-16-171-AE The results show the importance of applying optimization and provided the optimized values of the studied parameters at each case. Also it shows that the application of the new idea of multi-burn rate base bleed increases the range in all cases with percentage up to 12 % with respect to the range increase for the original base bleed grain.