Departure-site spacing for liquid droplets and jets falling between horizontal circular tubes

When a liquid film falls from one tube to;another below it, the How can lake the form of discrete droplets, individual jets or a continuous sheet. Experiments exploring the effects of thermophysical properties and geometrical parameters on the droplet and jet flow patterns are described. Measurements of droplet and jet departure-sire spacing are reported for several fluids over a wide range of liquid flow rates, tube sizes and tube spicing. For the conditions of this study, departure-site spacing increased with decreasing Re for high-Ga fluids and was nearly independent of Re for low-Ga fluids. Departure-site spacing increased slightly with tube diameter for small tubes and was nearly independent or tube size for large tubes. Departure-site spacing was nearly independent of tube spacing for the entire range of experiments; however, a relation between jet shape, jet spacing and tube spacing was observed under some conditions. A qualitative study of liquid-jet shapes shows that this How feature depends strongly on tube spacing, and comparisons to existing models suggest that further work in this area is needed. (C) 1998 Elsevier Science Inc. All rights reserved.