Research On Barrel Temperature Field Calculation And Barrel Cooling Technology For Gatling Weapons

With the rapid development of modern science and technology,the rotary barrel weapon has gradually become an indispensable part of the air defense system.As the rotary barrel weapon develops in the direction of high RF,high stability and high fire density,its firing process is subjected to more heat load from the gunpowder gas,which makes the barrel face problems of ablation,wear and tear,and projectile spontaneous combustion,etc.,and the thermal factor is the key to study these problems.In this paper,the heat transfer law of a 30 mm gatling weapon barrel is studied and the thermal stress of the barrel during firing is investigated as follows:a)Establishing a heat transfer model of the barrel coupled with classical internal ballistics and analyzing the heat transfer law during projectile firing.The Lagrange assumption is used to obtain the flow field parameters in the post-bullet space at any time of the barrel,and the third type of boundary conditions for the heat transfer problem of the barrel are solved.The finite difference method in ADI iterative format is used to derive and establish the set of controlling equations for the thermal conductivity of the barrel.The mesh of different wall thicknesses of the barrel is divided by the method of variable section step,and the temperature field of the barrel is calculated according to the model for single shot and multiple shots.During the firing process of the projectile,the temperature of the inner wall reaches up to 1426 K,and then decreases gradually.After firing,the overall temperature distribution shows a pattern of lower temperature nearer to the muzzle and higher temperature at the outer wall,except for the lower temperature at the bottom of the chamber.(b)Based on the cross-sectional model of the barrel,the characteristics of the convective heat transfer coefficient of the outer wall of the rotating tube weapon are given,and the finite element method is applied to establish the heat transfer model of the barrel under different cooling methods on this basis.The flow field characteristics of the outer wall of the rotating barrel and the effects of interlayer cooling and chromium plating layer on the heat transfer of the barrel are studied.The results show that the chrome plating layer will reduce the inner wall maximum temperature during the firing process,but will accelerate the heat transfer,and the interlayer cooling is beneficial to the temperature reduction of the barrel,but the effect is not significant in a short period of time.c)The temperature field of the whole barrel during the launch is solved by writing the heat load on the inner wall of the barrel with the movement of the projectile and defining the third type of boundary conditions on the inner wall of the barrel.The thermal stresses of the barrel with different inner wall materials at different moments are analyzed.The results show that the barrel containing plating can reduce the maximum value of thermal stress inside the barrel at the same position.