Numerical Simulation of Heat Loss Model Based on Gas-solid Two-phase Flows in a Gun Bore

Abstract

The heat loss during the firing process of artillery will affect the performance of interior ballistics. In numerical simulation, it is difficult to calculate the heat loss directly, so the method of modifying the propellant force or the adiabatic index of the gas is usually used, but this way cannot accurately predict the performance of the interior ballistics. Therefore,a calculation method of heat loss based on gas-solid two-phase flow model was proposed in this paper. Starting from the heat exchange between high-temperature gas and the inner wall of the barrel,a heat loss model was established,and the heat loss model was coupled with the gas-solid two-phase flow model in the gun bore,and the heat loss would be considered in the source term of the gas phase energy conservation equation. Taking a 155 mm gun as the research object,the modified gas-solid two-phase flow model was solved using MacCormack difference scheme to obtain the change of the flow field in the bore. The flow-field parameters obtained were used as the input parameters of the heat loss model and the heat transfer model of the barrel,and the total heat loss in the internal ballistic process and the radial temperature distribution of the barrel was calculated. Through the simulation calculation of the two test conditions given in this paper, the comparison between the calculation results and the experimental results shows that the error of each index is significantly reduced while considering the heat loss;the maximum pressure error is less than 1.0%;the initial velocity error is less than 0.5%. The total heat loss accounts for 2% ~ 4% of the total energy generated by the powder after combustion. The feasibility and superiority of this method were proved. The study is useful to improve the accuracy of interior ballistic simulation.