Transient heat transfer characteristics of air-array-jet impingement with different nozzle arrangements on high-temperature flat plate in small jet-to-plate distance

Numerical studies on transient heat transfer characteristics of air-array-jet impingement with a small jet-to-plate distance and a large temperature difference between nozzles and plate were presented. The dimensionless jet-to-plate distance( H/D) was 0. 2,and non-dimensional nozzle-to-nozzle spacing( S/D) was 3,4,5 and 6,respectively. It is found that the quenching time is shortened at a constant total mass flow at air jet inlet ■( ■= 218.21 kg/h),and the heat transfer uniformity is deteriorated as S/D increases. However,the adding reversed-flow nozzles can shorten the quenching time of the glass plate considerably with a modest change in the heat transfer uniformity. The results at variable ■ are the same as those at a fixed ■. Furthermore,the parity and arrangement of nozzles are also discussed,It is found that an odd number of nozzles is more beneficial for transient heat transfer. Based on these results,an appropriate proposal for ultra-thin glass tempering process is presented.