... temperature of air at the inlet will drop somewhat as a result of heat loss through the duct whose surface is at a lower temperature The properties of air at atm and this temperature are (Table A- 15) ρ... temperature of air at the inlet will drop somewhat as a result of heat loss through the duct whose surface is at a lower temperature The properties of air at this temperature and atm are (Table A- 15) C... (250+150)/2=200°C are (Table A- 15) C p = 1023 J/kg.°C R = 0.287 kJ/kg.K Also, the heat of vaporization of water at atm or 100°C is h fg = 2257 kJ/kg Analysis The density of air at the inlet and the mass flow