Selection of suitable sub-models for improved confidence in lumped parameter internal ballistic codes

Abstract

Gun systems manufacturers, propellant manufacturers, ballisticians, and the users of gun systems heavily rely on interior ballistic simulations to describe projectile behavior from the initial point of propellant ignition until the projectile leaves the gun muzzle. The simulation of interior ballistics plays a significant role in optimizing the overall ballistic system, control changes, associated cost, and the minimization of related risks. One of the most commonly used models to simulate the interior ballistic cycle is the lumped parameter model for interior ballistics. The North Atlantic Treaty Organization (NATO) has standardized a lumped parameter model that is known as STANAG 4367 (Moreno, 2009). However, during work routines, it is noticed that when the lumped parameter model of STANAG 4367 is used to simulate a 155 mm artillery system, it predicts the muzzle velocity and maximum chamber pressure of 155 mm artillery system with relatively high deviation. The problem is found to be with the heat transfer model of STANAG 4367. The primary aim of this research is to find a better alternative to the heat transfer model of STANAG 4367 that is more suitable for simulating a 155 mm artillery system. This research also aims to develop a practical interior ballistic simulation program to be used in different applications of interior ballistics. It also aims to provide guidelines for interior ballistic simulation procedures when the ballistic system has a constant or variable gun wall thickness.