Non-uniform melting of a spherical ice particle in free ascending

In order to achieve a thorough understanding of the flow and heat transfer characteristics of phase change slurry, melting process of a spherical ice particle during free ascending in resting water can provide fundamental knowledge. The motion of the ice particle is depicted by the momentum equation while the flow and heat transfer are described using the enthalpy-porosity model to take the phase change into account. The ascending and melting characteristics at different superheating degrees of water as well as supercooling degrees of the ice particle are investigated. The results show that the spherical ice particle first accelerates to the maximum velocity of approximately 0.04 m s(-1) under the effect of buoyancy, and then gradually decelerates as the ice particle melts. The superheating degree of water has a significant influence on the movement and melting characteristics of the ice particle while the supercooling degree imposes negligible effect. The variations in morphology and the local heat transfer coefficient of the ice particle are obtained and analyzed. It is found that the local heat transfer coefficient on the surface of the ice particle significantly influences the morphology of the ice particle during melting, which appears as sphere, ellipsoid, barrel shape and oval shape, sequentially. (C) 2019 Elsevier Ltd. All rights reserved.