Air at 50 deg C and 1 atm flows over the surface of a water reservoir at an average velocity of 2.3 m/s. The water surface is 0.61 m wide. The water surface temperature is estimated to be 30 deg C. The relative humidity of the air is 40 %. Estimate the water vapor transfer per hr per sq.m. Density of air = 1.105 kg/m3 Viscosity of air = 1.943 x 10-5 kg/m.s Diffusivity of water in air = 0.256 x 10-4 m/s Partial pressure of water at 30 deg C = 4.24 x 10-3 N/m2 Saturation pressure of water at 50 deg C = 12.34 x 103 N/m2 M = 0.0296 Re-0.2 = (kw/u) Sc23 R=8315 J/KOK MW of air: 27 (dry), 29 (moist)