EVAPORATIVE COOLING OF A FALLING WATER FILM ON HORIZONTAL TUBES

Results of experiments on evaporative cooling of water,falling freely from one horizontal tube to the next one below it are presented in the paper. Smooth, unheated tubes (diameter 19.5 mm) were arranged one up on the other in the same vertical plane. Water was uniformly distribut ed along the apex of the most upper tube, the water flow exposed to up wardly streaming air, and change of the water temperature in the flow direction was measured. At specified inlet conditions, the reduction o f water temperature was observed to depend on the humidity and velocit y of the air, and on the tube spacing. Based on the experiments, an em pirical equation for calculating the evaporative water cooling is reco mmended. (C) 1998 Elsevier Science Inc. All rights reserved.