Analysis of the Effect of Propellant Temperature on Interior Ballistics Problem

Abstract

This study investigates the effect of conditioning temperature of double base propellants on the interiorballistic parameters such as burning gas temperature, barrel wall temperature, pressure and stresses generated inthe barrel. Interior ballistic problem was solved employing experimental, numerical and analytical methods witha thermo-mechanical approach. Double base propellants were conditioned at different temperatures (52, 35, 21, 0,-20, -35, -54oC). The maximum pressure in the barrel and projectile muzzle velocity were measured for all thepropellants by conducting shooting tests with a special test barrel using 7.62x51 mm NATO ammunition. Vallier-Heydenreich method was employed to determine the transient pressure distribution along the barrel. Thetemperature of burnt gases was calculated by using Noble-Abel equation. The heat transfer analysis was doneusing the commercial software ANSYS to get the transient temperature and stress distributions. Temperaturedistribution through the barrel wall thickness was validated using a FLIR thermal imager. Radial, circumferentialand axial stresses and corresponding equivalent Von Misses stresses were determined numerically andanalytically. The results of the analytical solution for stress analysis validated the finite element solution of interiorballistic problem. Increasing the initial temperature of the propellant resulted in higher temperature and pressureinside the barrel which in turn increased the stresses in the barrel.