内弹道对自动步枪枪管瞬态温场影响计算分析

为了探究在2种不同的内弹道条件下自动步枪连发射击过程中枪管温度场的差异,建立了普通自动步枪身管三维传热模型,通过试验验证了模型的正确性。进行了瞬态温度场仿真计算,得到了“膛压缓和上升内弹道方案”和“膛压快速上升内弹道方案”2种内弹道条件下30发和150发连续射击后枪管温度场与位移场的空间分布及演化情况。计算结果表明:“膛压缓和上升内弹道方案”与“膛压快速上升内弹道方案”相比,瞬态温度和位移上升速率更大。第一个方案除枪管尾部区域略低外,其他大部分区域瞬态温度分布较高,且温度引起位移变形也变大。2种方案的差异在膛口处达到最大值。瞬时高温对内壁产生烧蚀作用,这对枪管寿命和冷热偏不利。因此自动步枪内弹道调整为膛压快速上升内弹道方案对步枪性能提升更有利。

Calculation and Analysis on Effects of Internal Trajectory on TransientTemperature Field of Automatic Rifle’s Barrel

In order to explore the difference of the temperature field and obtain the temperature field of the gun barrel under two different loading conditions during continuous firing,a 3D thermal-transfer model of a normal barrel was established and verified by a particular experiment.The model was used in a simulation,in which the time distribution and the space distribution of the displacement field and temperature field after 30 shots and 150 shots were calculated. Compared with the plan that gun pressure rises rapidly,the plan that the gun pressure rises moderately,has higher climbing speed of transient barrel temperature and displacement.Except the lower end of the barrel,most area of the barrel in the first plan shows higher transient temperature and larger displacement.The difference of two plans reaches the maximum at the muzzle. Instantaneous high temperature produces ablative action to inner wall of the barrel,which has a bad effect on barrels’life and accuracy. It is better for automatic rifles’performance to change the moderate-rise plan to rapid-rise plan.