Interior Ballistic Modeling and Simulation for Different Charge Zones in Modular Charge System

The modular charge is developed to replace the conventional bagged charge systems for many advantages. In the interior ballistic cycle of a modular charge system, the nonsimultaneous ignition of propellant in different cases results in an increasing pressure wave, and can cause a launch safety problem of the gun. Because the charge structure is complicated, it is hard to simulate the interior ballistics process for the modular charge system currently. To simulate the interior ballistic of the modular charge system more accurately, an improved interior ballistic one-dimensional two phase flow model for modular charge system is established. The improvement of this model lies in that it takes account of the discontinuity of the propelling charge bed, the block of the cartridge wall to the flame spreading in propelling charge bed, effects of modular cartridge movement to the interior ballistic performance, the nonsimultaneous breakup of the modular charge cartridges, the ignition of the propelling charge in different cartridges, and flame spreading through the cap of the core tubes. Simulation for a full charge and three lower charge cases with different charge position were carried out based on the model. The simulation results proved that the model is reliable, and can be used to study the effects of cartridge mechanical properties, charge position, different charge zones on interior ballistic performance of modular charges.