Heat Transfer Characteristics of Cooling High Temperature Steel Plate by Single Round Jet Impingement

The heat transfer characteristics of a single round air jet impingement on a high temperature steel plate were examined experimentally using a single-point temperature measurement method, incorporated with solving the inverse heat conduction problem. During the experiments, the temperature of the steel plate varied from 1073 K to 373 K, the Reynolds number was set to 27,000, the nozzle to plate spacing was set to 4. The results indicated that the radial distribution of the local Nusselt number is bell-shaped at the initial stage of the transient cooling process. As the cooling process continues, the local Nusselt numbers decrease and a second peak occurs at r/D = 2. The area averaged Nusselt number are in accordance with the correlation proposed by Hofmann and Martin at first and then decrease significantly, but this trend is not obvious at r/D > 10. (C) 2014 Wiley Periodicals, Inc. Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj).