Numerical modelling and simulation of heat transfer for micro-sized spherical Al-4.5 wt% Cu alloy particles

Pulsated Orifice Ejection Method (POEM) is a typical containerless heat transfer and solidification process for the preparation of micron-sized spherical particles. The heat transfer mechanism dominated by convection and radiation plays crucial roles. In the context of the preparation process, heat transfer, and solidification characteristics of micrometer-sized spherical metal particles using the POEM , this paper established a numerical calculation model for particle heat transfer and solidification in a three-dimensional polar coordinate system. The model is used to simulate the temperature variations and distribution characteristics at different stages of the solidification process of Al-4.5 wt% Cu alloy particles. The temperature gradient, cooling rate, advancement of the liquid–solid interface, and solidification rate during the particle solidification process were investigated. Additionally, the dominant mechanism of heat transfer in the particle solidification process was discussed, subsequently allowing for the calculation and analysis of the convective and radiative heat transfer characteristics as well as their respective contributions. On this basis, the influence of two different cooling gases on the particle solidification process was explored. The results of this paper demonstrated that convective heat transfer is the main mechanism of heat transfer during particle solidification. Besides, He gas has a stronger effect on the heat transfer of particles than Ar gas. It will benefit the optimization of the preparation process and the regulation of the solidification process for micrometer-sized spherical particles using the POEM.