EXPERIMENTAL-STUDY FOR HEAT AND MASS-TRANSFER IN WAVY FILM ABSORPTIONWITH THE PRESENCE OF NONABSORBABLE GASES

Experimental measurements for the heat and mass transfer in laminar wa vy film absorption with the presence of non-absorbables are presented. Water vapor was absorbed into a falling film of aqueous lithium chlor ide solution on a vertical tube with the air present in the gas phase acting as the non-absorbable whose concentration was accurately detect ed by a mass spectrometer gas analyzer. Although the depressing effect of the air on the absorption rate was much more significant in the lo w air concentration range, the absorption reduction rate with increasi ng air concentration was found to be lower than that reported previous ly. The reduction was found to be continuous even up to 30% of air con tent. Besides the non-absorbables, the effects of other operational pa rameters such as solution flow rate, inlet solution temperature, inlet solution concentration, absorber wall temperature, absorber water vap or pressure, and effective contact length on the absorption rate were also tested. These effects were shown to follow trends similar to thos e predicted by a numerical solution for smooth film absorption. The he at and mass transfer coefficients were correlated by using Reynolds nu mber, Prandtl number, Schmidt number, capillary-buoyancy coefficient a nd air concentration.