JFET_V8_N3_RP3 Venkata Ramana Subbarao chirravuri Gopal singh P.V. Krishna Prasad K.M.M. Journal on Future Engineering and Technology 2230 – 7184 8 3 22 27 Drag Reducing Agents, Hydrotrope, CTAB, Exit Pipe Using drag reducing agents, experiments on efflux time are performed for ascertaining drag reduction during gravity draining of a liquid from a large cylindrical storage tank through an exit pipe. The drag reducing agents used are water soluble sodium salicycalate, a hydrotrope, Cetyl trimethylammonium bromide, a cationic surfactant (CTAB) and mixed solutions consisting of CTAB and sodium salicylate(SS). The experiments are performed using different weight ratios of sodium salcylate and CTAB. Optimum concentrations for all the three cases have been established. The diameter of storage tank diameter of the exit pipe and lengths of exit pipe are kept constant while performing experiments. The experiments are also performed for different volumes of liquid in the tank. It has been observed that the optimum concentration (minimum efflux time) for all the cases is independent of volume of liquid in the tank. The drag reduction ( i.e reduction in efflux time) with mixed solutions of sodium salicycalate and CTAB at 100 ppm is observed to be comparable with that of CTAB alone at 1000 ppm. February - April 2013 Copyright © 2013 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=2218