(Solved): Hot air at pressure 1 atm and temperature 85C enters a 10m-long uninsulated square duct of cross ...

Hot air at pressure 1 atm and temperature 85°C enters a 10m-long uninsulated square duct of cross section 0.15 m x 0.15 m that passes through the roof space of a house at a rate of 0.10 m³/s. Assume duct temperature is constant at 65°C, determine: a. Reynolds number of air flow. b. Heat transfer coefficient, assuming the flow fully developec' c. The exit temperature of the air. d. Logarithmic mean temperature difference e. The rate of heat loss from the duct. Assume the properties of air at 1 atm. Attic cp=1.009 [kJ/kg.K] v=0.00002155 [m²/s] space k=0.02988 [W/m-K] p=0.9824 [kg/m³] Pr=0.7147 Air 85°C 0.1 m³/s 65 °C