Heat transfer in a 155 mm compound gun barrel with full length integral midwall cooling channels

When firing, large amounts of heat flow into the gun bore surfaces and result in wear and erosion of the gun bore. Moreover, the chamber surface temperature will reach the cook-off temperature of propellant during long sustained firing, which will impact on user safety and facilities. For large-caliber gun, a serious limitation on the weapon’s availability for action is imposed with high-energy propellants used and firing rates increasing. An effective method for solving this problem is to adopt barrel liquid-cooling technique. In this paper, heat transfer in a 155 mm midwall cooled compound gun barrel was analyzed theoretically. For the reference, heat transfer in a naturally cooled monobloc gun barrel was also discussed. Finite element analysis (FEA) method was employed to validate the results obtained by theoretical analyses. The present study showed: (1) natural air cooling is ineffective for transferring the heat out of the barrel because the combined convection and radiation heat transfer coefficient is relatively small; (2) forced midwall cooling has great heat extraction capability and is able to keep the chamber temperature below the cook-off temperature by increasing the heat transfer coefficient; (3) an optimal flow rate should be selected to balance the cooling efficiency and the pressure loss.