顺序凝固工艺对大长径比装药缩松的影响研究

A study on the effect of sequential solidification process on microporosity in large aspect ratio charge

针对顺序凝固工艺对大长径比装药易形成缩松的问题,分别以受控生长期、自由凝固期的相界面形貌特征参数为中间量,建立了工艺参数到缩松体积的4层关联路径,选择TNT/RDX(33.8/65)炸药、长径比5∶1的装药模具,进行了正交仿真、极差分析以及Spearman相关系数计算,结果表明,降低水温、入水速度以及提高环境换热系数可提高受控生长期的相界面高度、开口角,从而降低自由凝固期的凝固区间最大厚度,最终减少缩松体积;工艺参数影响强弱为:水温、入水速度、环境换热系数;降低入水速度、提高环境换热系数可减少对低水温的依赖。本研究探明了顺序凝固工艺参数对大长径比装药相界面演化及缩松的影响机理,可为相关工艺设计提供理论支撑。

Aiming at the microporosity in large aspect ratio charge by sequential solidification process,the interface morphology characteristics in controlled growth period and free solidification period was used as intermediate variable to establish a four-layer correlation path from process parameters to shrinkage volume.TNT/RDX(33.8/65)and charge mold with aspect ratio of 5∶1 were selected for orthogonal simulation,range analysis and Spearman correlation coefficient calculation.The results show that:reducing water temperature,water entry speed and improving environmental heat transfer coefficient can increase the phase interface height and opening angle in the controlled growth period,thereby reducing the maximum solidification interval thickness in the free solidification period and ultimately reducing the shrinkage volume.The process parameter influence ranking is:water temperature,water entry speed,environmental heat transfer coefficient.Reducing water entry speed and improving environmental heat transfer coefficient can reduce the dependence on low water temperature.This study has revealed the influence mechanism of process parameters on the phase interface evolution and shrinkage of large aspect ratio charge in sequential solidification process,which can provide theoretical support for relevant process design.