2.17b. Mass transfer in a wetted-wall tower Water flows down the inside wall of a 25-mm-ID wetted-wall tower of the design of Figure 2.4, while air flows upward through the core. Dry air enters at the rate of 7 kg/m2.s. Assume the air is everywhere at its average conditions of 309 K and 1 atm, the water at 294 K, and the mass-transfer coefficient constant. Compute the average partial pressure of water in the air leaving a tower 1-m-long. Answer: 1.516 kPa Liquid in olembar Feed reservoir Pipe wall Liquid film Wetted-wall section Calming section Liquid out Gas Figure 2.4 Wetted-wall tower