The final step of a manufacturing process in which a protective coating is applied to the inner surface of a circular tube involves passage of dry, atmosphere air through the tube to remove a residual liquid associated with the process. Consider a coated 5-m-long tube with an inner diameter of 50 mm. The tube is main- tained at a temperature of 300 K, and the residual liquid exists as a thin film whose corresponding vapor pres- sure is 15 mm Hg. The molecular weight and diffusion coefficient of the vapor are MA = 70 kg/kmol and DAB = 10-5 m2/s, respectively. Air enters the tube at a normal body temperature of 37°C and may be assumed to be saturated with water.
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(a) Assuming steady, fully developed flow in the trachea, estimate the mass transfer convection coefficient.
(b) Estimate the daily water loss (liter/day) associated with evaporation in the trachea.