Thermal diagnostics of highly heated surfaces using water-spray cooling

Spray cooling of heated surfaces is common in many industrial applications, notably steelmaking, because of its high heat dissipating ability. Control of the surface heat flux rate contributes to better products; it is shown that the heat transfer rate depends on the mass fraction of liquid. Quantitative information regarding the parameters affecting spray cooling is relatively scarce. The rate of heat transfer from a plate due to impinging of an array of water jets was investigated numerically through the solution of heat conduction equation. The simulation is carried out for eight different sprayers, in the range of ejected fluid pressure between 1 bar and 3 bars. Experimental data are used to study the influence of the function g(x, y), of dispersed water, on heat transfer variations across the surface at the temperature of 600°C. Curves were generated showing time histories of the steel temperature for the removal of high heat fluxes of the order of 300 W/cm². It was also observed that for lower temperatures, the predicted local heat transfer coefficient increased significantly. In memory of H. Mzad’s father Mebrouk.