Heat Transfer Characteristics from Single Group Slot Jet Impingement on the Strip Surface for the Hot Rolling Ultra-Fast Cooling

Abstract

As for the impinging jets of single group slot nozzles, the heat transfer of the top and bottom strip surface is uneven which is mainly caused by the various jet distances of the top and bottom nozzle to the strip surface and the effect of gravity. In this study, the convective heat transfer process of the top and bottom strip surface due to single group slot nozzles in the ultra-fast cooling (UFC) system was studied by the fluid-structure interaction finite element method. The distributions of the flow field and heat transfer for the top and bottom strip surfaces were obtained under the various parameters. The results showed that, the difference value of the average Nusselt numbe for the top and bottom strip surface was decreased with the increase of the jet velocity, but when the jet velocity was up to 5m/s it remained almost the same. The uniformity of the top and bottom surface was improved by the jet impingement height (h) for the h<45mm. It was found that for h=25mm, the heat transfers of the top and down surfaces were more evenly, and the different value of average Nusselt number for the decreased by about 12.6%-28% as the jet impingement height increased from 25mm to 45mm when the slot width was 5mm.