Atmospheric pressure air is heated in a long annulus (25 cm ID, 38 cm OD) by steam condensing at 149?C on the inner surface. If the velocity of the air is 6 m/s and its bulk temperature is 38?C, calculate the heat transfer coefficient.GIVENAtmospheric flow through an annulus with steam condensing in inner tubeDiametersInside (Di) = 25 cm = 0.25 mOutside (Do) = 38 cm = 0.38 mSteam temperature (Ts) = 149?CAir velocity (V) = 6 m/sAir bulk temperature (Tb) = 38?CASSUMPTIONSSteady stateSteam temperature is constant and uniformHeat transfer to the outer surface is negligibleAir temperature given is the average air temperatureThermal resistance of inner tube wall and condensing steam is negligible (Inner tube wall surface temperature =Ts)

Transcribed Image Text:

Alr T- 38°C V=6 m/s Do- 38 cm D- 25 cm Steam T- 149°C