A stream of air at 500C and 835 torr with a dew point of 30C flowing at a rate of 1515

Chapter 8, Problem 8.38

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A stream of air at 500C and 835 torr with a dew point of 30C flowing at a rate of 1515 L/s is to be cooled in a spray cooler. A fine mist of liquid water at 15C is sprayed into the hot air at a rate of 110.0 g/s and evaporates completely. The cooled air emerges at 1 atm. (a) Calculate the final temperature of the emerging air stream, assuming that the process is adiabatic. (Suggestion: Derive expressions for the enthalpies of dry air and water at the outlet air temperature, substitute them into the energy balance, and use a spreadsheet to solve the resulting fourth-order polynomial equation.) (b) At what rate (kW) is heat transferred from the hot air feed stream in the spray cooler? What becomes of this heat? (c) In a few sentences, explain how this process works in terms that a high school senior could understand. Incorporate the results of Parts (a) and (b) in your explanation.