Two-Phase Flow Interior Ballistics Model of Naval Large caliber Guided Projectile Gun System

The two-phase flow mathematical model for the solid granular propellant and its products of combustion inside large caliber naval gun guided projectile system (NGGPS) during interior ballistic cycle is presented. The model includes the governing equations of mass, momentum and energy for both phases as well as the constitutive laws. The discharged combustion products from the igniter vent-holes into the chamber are acquired by incorporation in the model the two-phase flow model of the bayonet igniter. The system of equations of the two-phase flow model is solved using the second order accurate Maccromack's technique. A one dimensional model introduced by G.A. Sod (shock tube) is utilized to test the ability of Maccromack's algorithm in solving the initial boundary value problem (IBVP) for the system of equations with shock wave behavior. The numerical method is verified by using an exact solution of a test problem. The moving control volume conservation method (MCVC) is used to handle the moving boundary as well as a self-adapting method was used to expand the computational domain in order to follow the movement of the projectile down the gun bore. The numerical results are validated with experimental data. The interior ballistics performance of a 130 mm naval guided projectile gun system is closely predicted using the presented two-phase flow model and the numerical code.