Ultrafast cooling processes with surfactant additive for hot moving steel plate

The study of ultrafast cooling of a hot moving surface is very important, as it is applicable in many industries, such as cooling of a hot steel strip on the run out table in steel industry. In general, the run out table is fitted with laminar water jets where the achieved cooling rate is very less because of the Leidenfrost phenomenon. The current research is focused on the comparative study of the cooling processes; by using water jet and air atomized spray cooling techniques on the hot stationary and moving surface. The coolant used in both the cases is surfactant added water with varying concentration of surfactants. In case of stationary bed, the maximum cooling rates achieved for both jet and air atomized spray cooling are at a surfactant concentration of 225 ppm, the values being 167 and 224 °C/s, respectively. On the contrary, for moving surface, highest cooling rates of 163 and 127 °C/s are obtained at a low surfactant concentration of 75 ppm for jet and spray cooling respectively. It is interesting to observe that addition of surfactant has a negative effect on cooling rate for a hot moving surface.