OR-20-024 -- Measurements of Spray Water Evaporation Rates for an Inflatable Fabric Duct Cooling Tower

This paper describes an experimental program that wasdesigned to quantify the rate of spray water evaporation intoa warm, dry airstream with application to a proposed inflatablefabric duct cooling tower. The inflatable nature of thefabric duct cooling tower promotes rapid deployment, andprovides low energy cooling for human comfort in hot, aridenvironments. The test apparatus measured the mass transfercoefficient for dispersed water droplets flowing parallel to aheated air stream. The data reduction approach employed theanalogy between forced convection heat transfer and evaporationmass transfer. For a specific misting nozzle used in aprototype inflatable fabric evaporative cooling tower, theexperiments demonstrated that the average test section Sherwoodnumber was a power-law function of the water-to-airmass flow rate ratio, with the exponent equal to 0.70. Likewisethe resulting Sherwood number was inversely proportional tothe downstream distance from the spray water injection.