Heat Transfer Characteristics of Various Gun Barrels Under Different Operating Conditions

Abstract

Abstract The thermal stability parameter is an important parameter for predicting the lifespan of structures. In this paper, a two-dimensional transient heat transfer model of machine gun barrels undergoing continuous firing developed and analyzed for different geometries and thermal properties. The model for the transient thermal analysis is based on the forced convection heat transfer at the inner surface of the gun barrel. Finite element simulations were performed to predict the interior and exterior barrel temperature profiles and temperature contours after continuous firing process. The incomplete Cholesky Conjugate Gradient (ICCG) solver was adopted in solving unsymmetrical thermal transient analyses. The material thermal behavior studied for the basic circular cross section of gun barrels showed that the lowest inner wall temperature was for high rounds was achieved in steel barrels due to the rapid conducted and convective heat transfer to the environment. While the highest inner wall temperature was recorded for ceramic STK4 barrels and an increase of inner wall temperature by 17% was observed as compared to the typical case of circular cross section steel barrel. In general, a higher inner temperature in the gun barrel is undesirable and harm due to the possibility of reaching the cook-off scenario at earlier rounds. Results concluded that non-circular geometries with constrained cross section areas of typical case improve thermal management and the hexagonal geometry had the best thermal management and could provide more rounds for users. In addition, titanium barrels would have a weight drop of 41% while the overall barrel’s temperature increases by 49%.