Numerical study on the thermal stability of modular charge in chambers considering heat transfer

Investigating the heat transfer and cook-off behavior of modular charge (MC) during continuous firing is crucial for ensuring the thermal reliability of large-caliber artillery under high-frequency firing conditions. At an ambient temperature of 15 °C, a heat transfer model coupled with an interior ballistic model is developed to analyze chamber temperature distribution under varying firing conditions. This distribution is utilized as the initial condition for a two-dimensional unsteady cook-off model to numerically analyze the cook-off reaction of loaded MC. Results show that the thermal stability of MC is influenced by firing rate, number of rounds fired, and the number of modules loaded in the chamber. Cook-off initiates at the top-right corner of the far-right module, forming a ring-shaped ignition zone. Increasing the number of modules shifts the ignition point axially leftward and extends the cook-off time. Across all conditions, the cook-off temperature range is 451–463 K. The maximum safe number of rounds to maintain module stability in the chamber is determined to be 44, 43, and 42 at firing rates of 6, 10, and 15 rounds/min, respectively.