1994 Volume 60 Issue 572 Pages 1401-1407
Two-dimensional jet impingement onto a circular cylinder of 50 mm diameter was studied. Particular attention was paid to a case when the cylinder was located in the converging flow field formed between the two flat plates mounted symmetrically near the cylinder. Nozzle-to-cylinder distance was changed in three steps, mainly 3, 7 and 10 times the nozzle width (15 mm), and the jet velocity was changed in the range of 8∼15 m/s. The effects of the narrower end of the converging flow space between the two plates and of the space between the cylinder and the plates on the flow-field and the heat transfer from cylinder were examined. In the case of relatively small cylinder-to-plate spacings, reattachment of the separated flow onto the cylinder surface was observed and the local Nusselt number was found to take a maximum near the reattachment point. Then, an increase by about 9∼12% of mean Nusselt number was obtained.