1974 Volume 6 Issue 5 Pages 409-414
This paper presents the characteristics of Newtonian heat transfer in an agitated vessel to or from (1) an impeller, (2) a doughnut plate, and (3) a draft tube. The heat transfer to the impeller is 2.5 to 3 times as large as that to the jacketed vessel wall over a wide range of Reynolds numbers. Doughnut plates appear to be useful as a heat exchanger in the region of low Reynolds number. The heating area maybe simply adjusted by changing the number of doughnut plates, and scraping of the plate surfaces is very easy. An agitator with propellers in a draft tube shows a slight decrease in heat transfer rate at high Reynolds numbers. However, it is a good heat exchanger in the range of low Reynolds numbers. For the agitation of highly viscous liquids, an agitator with a helical screw in a draft tube may be very favorable for industrial use.