Water at a mean temperature of 80 °C and a mean velocity of 0.15m/s flows inside a 2.5 cm ID and 3.3 cm OD, copper tube.Atmospheric air at 20 °C and a velocity of 10 m/s flows across thetube. Calculate the overall heat transfer coefficient based on theouter surface and the rate of heat loss per 1 m length of the tubefor inside and outside fouling factor 0.00018 m2. What is thepercent reduction in the overall heat transfer coefficient due tothe dirty conditions in the heat exchanger? (Assume that the valuethe waterside heat transfer coefficient is 250 W/m2.°C and that ofthe airside is 75 W/m2.°C.
