High Explosive Anti-Tank (HEAT) warheads and ammunitions are frequently produced by explosive casting inside an axis-symmetric mold with an inverted conical geometry in the basis. In order to prevent manufacturing defects, the solidification process must be controlled. In this study, a dimensionless solidification model has been proposed to investigate the heat transfer considering the natural convection inside the liquid explosive and the numerical simulations were performed by using COMSOL Multiphysics and Modeling Software, employing trinitrotoluene (TNT) thermophysical properties. The effect of three different boundary conditions on the top of the mold have been evaluated: convection, adiabatic and isothermal. It has been observed that solidification process was faster for convection case and slower for isothermal case, while an intermediary total solidification time value was found for adiabatic case. Moreover, liquid explosive was completely surrounded by solid explosive during the solidification process for convection case and also for adiabatic case through the end of the process. Otherwise, it was not observed for isothermal case. The natural convection effects promoted a vortex inside the liquid explosive, accelerating the heat transfer process. It has been concluded that isothermal mold top boundary condition should be preferred to prevent manufacturing defects, avoiding high thermal stress.

高爆反坦克 (HEAT) 弹头和弹药通常通过在具有倒锥形几何形状的轴对称模具内进行爆炸铸造来生产。为了防止制造缺陷，必须控制凝固过程。在这项研究中，提出了一个无量纲凝固模型来研究考虑液体炸药内部自然对流的热传递，并使用 COMSOL Multiphysics 和建模软件，利用三硝基甲苯 (TNT) 的热物理特性进行了数值模拟。已经评估了三种不同边界条件对模具顶部的影响：对流、绝热和等温。已经观察到，对流情况下的凝固过程更快，等温情况下的凝固过程更慢，而绝热情况下的中间总凝固时间值。此外，液体炸药在对流情况下的凝固过程中被固体炸药完全包围，在过程结束时绝热情况下也是如此。否则，在等温情况下没有观察到。自然对流作用促进了液体炸药内部的涡流，加速了传热过程。已经得出结论，应首选等温模具顶部边界条件，以防止制造缺陷，避免高热应力。在等温情况下没有观察到。自然对流作用促进了液体炸药内部的涡流，加速了传热过程。已经得出结论，应首选等温模具顶部边界条件，以防止制造缺陷，避免高热应力。在等温情况下没有观察到。自然对流作用促进了液体炸药内部的涡流，加速了传热过程。已经得出结论，应首选等温模具顶部边界条件，以防止制造缺陷，避免高热应力。