A pair of pore formation affected by convection during unidirectional solidification

The effects of convection on the shapes of pores resulting from entrapped double bubbles during unidirectional solidification are numerically and theoretically investigated. Bubble formation results from supersaturation of a dissolved gas in water ahead of the solidification front. Pore formation and its shape in solid influence not only microstructure of materials, but also biology, engineering, foods, geophysics and climate change, etc. In this study, conservation equations of fluid flow, heat transfer and solute concentration are solved by using commercial COMSOL computer code to simulate development of two bubbles entrapped as pores in ice. It is found that convection results in deviation of the leading pore and bigger size of the second pore. The associated transport variables are also presented. This work is critical to understand and control different types and sizes of pore shapes and their distributions in the solid in advance.