Numerical investigation on the unsteady spray cooling of high temperature steel plate.

• The accuracy of three locations temperature was verified by comparing with available experimental data. • The wall-jet model is a necessary mathematical model for the simulation of the high temperature spray cooling. • The surface temperature exhibited spatial non-uniformity cooling characteristics in the nucleate boiling regime. • The increase of the droplet velocity is beneficial to the cooling efficiency. In order to enhance the intensity and other mechanical properties of the steel, fast cooling technique is generally employed in the metallurgical industry. In the present paper the spray cooling characteristics during steel making process were numerically studied by CFD. A two-phase flow model was established based on the Euler-Lagrangian method. The Lagrangian method was applied to account for the behavior of the discrete droplets while the Eulerian scheme was employed to describe the continuous phase. The wall-jet and Lagrangian wall-film models were applied according to the surface temperature. The accuracy of the model was verified by comparing the temperature with available experimental data. The heat transfer characteristics and metal cooling characteristics during spray cooling were studied and the heat transfer mechanisms during film boiling, transition boiling, nucleate boiling and forced convection regimes were analyzed. The surface temperature exhibits spatially non-uniformity due to the cooling characteristics relating to the flow field of the spray. The influence of the droplet velocity was investigated and the results show that the cooling speed is accelerated with the increase of the droplet velocity and the peak of the heat flux is also corresponding with higher surface temperature. [ABSTRACT FROM AUTHOR]