双层管状变燃速发射药的燃气生成规律

Gas Generation Rule about Tubular Gun Propellant with Two Different Burning Rate Layers

为建立气体生成猛度Γ与已燃发射药质量分数Ψ的理论表达式,对双层管状变燃速发射药的燃气生成规律进行了理论分析。在服从几何燃烧定律的条件下,以双层管状药的初始药形尺寸及内外层药的燃速比、密度比为基本变量,推导出变燃速发射药的Γ-Ψ表达式,得出发挥双层变燃速管状药渐增性燃烧特点所需的临界长径比。通过Γ-Ψ计算曲线,说明这种发射药的内径、长径比及燃速比影响其燃气生成规律。结果表明,当双层管状发射药的初始药形尺寸及内外层药的燃速比取值适当时,会出现前期为渐增性燃烧、中后期有一个Γ值的阶跃情况。

To establish the Г vs. ψ expression, the gas generation rule about tubular gun propellant with two different burning rate layers was theoretically analyzed. Under the precondition of following the geometric combustion law, the equations describing Г vs. ψ relation of this kind of variable burning rate gun propellant were derived by using its initial geometric size, burning-rate ratio and density ratio of internal and external layer as the basic variables. The critical length-to-diameter ratio needed for elaborating the characteristics of progressive combustion of this gun propellant was obtained. The influences of inner diameter, length-to diameter ratio and burning-rate ratio of this gun propellant on its gas generation rule were discussed through calculated Г-ψ curve examples. The calculated results showed that this tubular gun propellants with two layers can present progressive combustion in early stage while a step of F in intermediate or late stage when the initial geometric size and burning rate ratio have proper values.