Calculate the overall heat transfer coefficient and the rate of heat flow from the hot gases to the cold air in the cross-flow tube bank of the heat exchanger shown in the accompanying illustration on the next page. The following operating conditions are given: 

air flow = 0.4 kg/s
hot gas flow = 0.65 kg/s
temperature of hot gases entering exchanger = 870°C
temperature of cold air entering exchanger = 40°C
Both gases are approximately at atmospheric pressure.

Transcribed Image Text:

Air in Heat exchanger, top view ^^^^^^^ Hot gas in Minimum flow area shown by heavy line 30 cm Tube detail Air in 2.5 cm- 22.6 cm ↓ 2.5 cm 5 cm 40 tubes -27.5 cm- Section A-A 2.5 cm 45 cm 22.5 cm