AC-1 Experimental Study of Air-Cooled Heat Exchanger Performance under Both Natural and Forced Draft Conditions
The HTRI air-cooled heat exchanger was operated under both forced and natural draft conditions, with steam inside the tubes. For the forced draft arrangement, despite the highly nonuniform air flow distribution, the results for both pressure drop and heat transfer were found to be very close to those previously obtained for an identical finned tube bundle in the wind tunnel.
For the natural draft arrangement, the heat duty of the exchanger was found to increase with increasing chimney height. Installation of a 4-ft (1.22-m) and an 8-ft (2.44-m) chimney increased the heat duties up to 1.8 times and 3 times respectively, as compared to the case without the chimney. A semi-empirical mathematical model has been established which predicts the natural draft heat transfer data with a maximum error of about ± 30 percent.