(517b) Numerical Modeling and Simulation Analysis of Casting of Energetic Material in a Projectile Controlled by the Active Cooling/Heating Solidification and Mechanical Vibration Technologies

This paper investigates the solidification shrinkage problem in casting of energetic material in a projectile. Special challenges that arise in casting highly viscous energetic materials in projectiles of complex geometries are addressed. An active cooling and heating (ACH) control solidification technology and mechanical vibration technology are applied to achieve unidirectional solidification during casting and to reduce shrinkage porosities.  Comprehensive numerical model is developed to simulate the heat and mass transfer processes during melt casting of energetic materials, as well as the resulting thermal stresses induced.  The design parameters of the proposed technologies are developed via numerical modeling.  In particular for the first technology, the media heating and cooling temperatures as well as the number of cooling/heating sections and their time sequences are optimized based on the mold diameter, thermo-physical properties of the energetic material, and mold thickness and type.  For the second technology, a resonant frequency of mechanical vibration was determined that helps to remove air entrapped during pouring process. It is demonstrated that the proposed technologies can successfully be applied to significantly minimize the solidification related defects (including macro-shrinkage and shrinkage porosities) in cast energetic materials.