快速烤燃条件下B炸药战斗部的临界泄压面积

Critical vent area of a Comp-B warhead under fast cook-off

为了确定战斗部装药在快速烤燃条件下能稳定燃烧的临界泄压面积,基于质量守恒定律和气体状态方程,建立了战斗部壳体内考虑炸药初始温度和排气孔排气的气体压力增长模型。以B炸药圆柱战斗部为研究对象,研究了炸药意外点火后能稳定燃烧的A_(V0)/S_(B)(临界泄压面积/炸药外表面积)确定方法,并与实验值进行了比较。结果表明,本文建立的模型能够很好地预测B炸药战斗部的临界泄压面积。研究了战斗部炸药装药表面积、炸药初始温度、空气体积占比和炸药燃速对A_(V0)/S_(B)的影响,并将不同温度的模型预测值与实验值进行了比较。结果表明:炸药装药表面积对A_(V0)/S_(B)基本没有影响;A_(V0)/S_(B)与温度和炸药燃速成正相关,与空气体积占比成负相关;不同温度的模型预测值A_(V0)/S_(B)与实验值吻合较好。

To determine the critical vent area over which a warhead can burn stably under the fast cook-off condition,the gas pressure rise inside the casing after the ignition of the warhead charge was studied under the fast cook-off stimulation based on the mass conservation law and state equation of gases.A gas pressure rise model was established in the current work by considering the initial temperature of the explosive and gas venting in a warhead.A composition B explosive(Comp-B)cylindrical warhead was used as the research object.The numerical calculation of the model was carried out to determine the A_(V0)/S_(B) ratio(critical vent area/external surface area of the explosive)at which the warhead could be in stable combustion after it was accidentally ignited.And the results were compared with experimental values.It is found that the change of pc(pressure inside the warhead casing)after the thermal stimulation and ignition of Comp-B occurred in four stages ofⅠ-Ⅳ:increased sharply,increased rapidly,decreased slowly,and finally,leveled off.The peak pressure of the warhead decreased linearly with the increase of A_(V)/S_(B).When A_(V)/S_(B) corresponding to the peak pressure(p_(cmax))of 10 MPa in the warhead was taken as the critical A_(V)/S_(B) ratio,A_(V)/S_(B) could better separate the stable combustion reaction from the explosion reaction inside the warhead.The effects of the warhead charge surface area,the explosive initial temperature,the air volume ratio,and the explosive burning rate on A_(V0)/S_(B) were investigated,and the model predictions at different temperatures were compared with the experimental results.The predicted values of A_(V0)/S_(B) agree well with the experimental results.It is found that the warhead charge surface area has little effect on A_(V0)/S_(B),andA_(V0)/S_(B) is positively correlated with the temperature and burning rate of the explosive and negatively correlated with the air volume ratio.The proposed model can well predict the critical vent area of the Comp-B warhead.Therefore,the findings of this study provide a theoretical basis for the design of thermally stimulated venting structures of ammunition.