Calculation of convection heat losses in interior ballistic processes

Gas dynamic calculation models were developed for interior ballistics. The flow equations in the form of partial differential equations are numerically solved. Convective heat losses occurring during one shot are calculated. In a one dimensional model they are calculated using a heat transfer coefficient obtained by the empirical Colburn formula. In a two dimensional model the gas flow behind the projectile is assumed to consist of a nonviscous main flow to which a turbulent boundary layer is coupled. The convective heat transfer is calculated from empirical profiles of average axial velocity component and temperature, or from two dimensional flow equations in the turbulent boundary layer.