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Modeling of ice crystal growth in laminar falling films for the production of pumpable ice slurries

2002; Elsevier BV; Volume: 44; Issue: 1 Linguagem: Inglês

10.1016/s0196-8904(02)00040-7

1879-2227

K.A.R. Ismail, Musa M. Radwan,

Freezing and Crystallization Processes

A generalized model has been developed to approximate the rate of ice crystal growth in a laminar developing falling film. In this model, the conservation equations of mass, momentum, energy and the transport equation governing ice crystal growth were solved numerically using finite differences based on the control volume method. The thermophysical properties of the mixture, such as density, specific heat, thermal conductivity and kinematic viscosity were allowed to vary in the flow field as a function of ice crystal concentration. The latent heat released by the ice crystals is considered as a source term in the energy equation. The results of the numerical simulations were analyzed based on the combined effects of the Reynolds (flow rate) and Stefan numbers on the ice crystal concentrations and the associated heat transfer parameters. The local Nusselt number at the solid surface and the overall heat transfer coefficient were primarily dependent on ice crystal concentration and, hence, the Stefan number. The overall heat transfer coefficient using ice slurry as a heat transfer fluid was compared to the case of a single phase chilled water system, illustrating the superiority of the ice slurry as a heat transfer and storage medium.