The fluid dynamics of multi-component alloy systems subjected to high energy density sources of heat largely determines the local composition, microstructure, and material properties. In this work a multi-component thermal fluid dynamics framework is presented for the prediction of alloy system development due to melting, vaporisation, condensation and solidification phenomena. A volume dilation term is introduced into the continuity equation to account for the density jump between liquid and vapour species, conserving mass through vaporisation and condensation state changes. Mass diffusion, surface tension, the temperature dependence of surface tension, buoyancy terms and latent heat effects are incorporated. The framework is applied to describe binary vapour collapse into a heterogeneous binary liquid, and a high energy density power beam joining application; where a rigorous mathematical description of preferential element evaporation is presented.

经受高能量密度热源的多组分合金系统的流体动力学在很大程度上决定了局部成分，微观结构和材料性能。在这项工作中，提出了一种多组分热流体动力学框架，用于预测由于熔化，汽化，冷凝和凝固现象而引起的合金系统的发展。体积膨胀项被引入到连续性方程中，以说明液体和蒸汽物质之间的密度跃变，并通过汽化和冷凝状态变化来节省质量。结合了质量扩散，表面张力，表面张力的温度依赖性，浮力项和潜热效应。该框架用于描述二元蒸气坍塌成非均质二元液体的过程，高能量密度功率束连接应用；给出了关于优先元素蒸发的严格数学描述。