Computational Fluid Dynamics (CFD) has been increasingly applied to heat treating processes in order to provide better part uniformity and to reduce residual stress and distortion. These simulations have been used to develop improved processing equipment and to determine surface heat flux rates for subsequent FEM analysis of individual parts. To date, most simulations of quenching processes have focused on isothermal, single phase flow due to the complexity of modeling boiling phenomena and the lack of good boiling models for application to industrial scale simulations.

A method is under development for modeling flow situations that include boiling, with specific application to quenching processes. The key features of this approach are nucleate and film boiling models that are based on a “wall model” concept, along with a transition model that switches between these two boiling models based on a combination of parameters, including wall temperature, fluid temperature, and fluid velocity patterns. A review of the theoretical basis behind these models will be presented along with correlation test data for a simplified geometry.