异形发射药结构设计与计算验证

Structural Design and Calculation Verification of Special-shaped Gun Propellant

针对内弹道性能模拟对发射药燃烧表面积计算的需求,提出了一种异形发射药药形计算与设计方法;设计了三角形柱状、梯形柱状和四边形柱状发射药,利用切分-独立计算-整体加和的计算原理,对其面积及体积随燃烧深度变化规律进行了计算;根据几何燃烧定律,推导了燃气生成猛度与发射药已燃百分数之间的函数关系,并讨论了内孔径对发射药燃烧渐增性的影响;对12孔梯形柱状发射药进行了试验验证。结果表明:异形发射药在内外弧厚保持一致、长宽比保持不变基础上,其理论燃烧过程呈增面燃烧的趋势,且随着孔径减小燃烧分裂点后移,但孔径变化对发射药燃烧过程影响有限。12孔梯形发射药的实际燃烧过程具有燃烧渐增性,但由于实际发射药尺寸以及点火一致性的偏差,测试结果与理论计算结果有一定误差。

A method for calculating and designing the shape of special-shaped propellants was proposed to calculate the burning surface area of propellants in the simulation of interior ballistic performance.The triangular,trapezoidal and quadrangular cylindrical propellants were designed.The change of surface area and volume with the burn depth was calculated using the principle of splitting-calculation-integration.The functional relationship between the generation intensity of gas and the combustion percentage of the propellant was deduced based on the geometric combustion law.Meanwhile,the effect of the inner-hole diameter on the incremental combustion performance of propellants was analyzed.The 12-hole trapezoidal cylindrical propellant was prepared to verify the accuracy of theoretical calculation.The results show that on the basis that the inner and outer web thickness remains the same and the length-to-diameter ratio unchanged,all the special shaped propellant possesses a progressive combustion characteristics.The splitting point moves backwards as the pore size decreases.However,the inner-hole diameter has a limited impact on the combustion process.The theoretical and experimental results of 12-hole trapezoidal cylindrical propellant deviate with each other resulted from size deviation and the ignition inconsistency.But,the 12-hole propellant still presents a combustion progressivity.