Effect of Inclination Angle and Flow Rate on the Heat Transfer During Bottom Jet Cooling of a Steel Plate

The heat transfer that occurs during bottom water jet impingement on a hot steel plate has been investigated in terms of the effect inclination angle and flow rate. This research was carried out to develop quantitative knowledge of the heat transfer, which occurs on the runout table, a crucial component in the hot rolling production of advanced high strength steels. Industrially produced hot-rolled steel samples were instrumented with numerous subsurface thermocouples installed close to the quench surface. The experimental measurements were used in conjunction with an inverse heat conduction (IHC) model to quantify boiling characteristics as well as heat extraction histories for the different nozzle inclination angles and flow rates. It was found that, as nozzle inclination angle increased, the degree of asymmetry of the cooled region on the surface of the sample was increased and the overall rate of heat extraction decreased. The angle of inclination had a significant effect on overall heat extraction; a vertical nozzle was the most efficient from a perspective of heat transfer under the nozzle. As expected, as flow rates increased, the amount of heat energy extracted increased for all the conditions studied, regardless of the nozzle inclination.