异形发射药结构设计与计算验证

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.