An engineer is designing a heating system which consists of multiple tubes placed in a duct carrying the air supply for a building. She decides to perform preliminary tests with a single copper tube, 2 cm o.d., carrying condensing steam at 100?C. The air velocity in the duct is 5 m/s and its temperature is 20?C. The tube can be placed normal to the flow, but it may be advantageous to place the tube at an angle to the air flow since additional heat transfer surface area will result. It the duct width is 1 m, predict the outcome of the planned tests.GIVENA copper tube carrying condensed steam in an air ductTube outside diameter (D) = 2 cm = 0.02 mSteam temperature (Ts) = 100?CAir velocity (U??) = 5m/sAir temperature (T??) = 20?CDuct width (w) = 1 mASSUMPTIONSSteady stateAir velocity in the duct is uniformThermal resistance due to steam condensing is negligibleThermal resistance of the tube wall isnegligible

Transcribed Image Text:

Duct Tube Alr Alr T= 20°C At an angle to flow Normal to flow