FLOW OF DRAG REDUCING FLUIDS THROUGH A SUDDEN ENLARGEMENT

Document Type : Original Article

Authors

Mechanical Power Engineering Department, Faculty of Engineering, Minufiya University, Egypt.

Abstract

Theoretical and experimental studies, of drag reducing dilute polymer solution flow
through a sudden enlargement, are carried out. A turbulence model, which has been
early used for predicting Newtonian flows with adverse pressure gradient (APG), is
developed in the present analysis. The developed model well predicts the fully
developed drag reduction flow in pipes, i.e. flow under favorite pressure gradient
(FPG) conditions besides the sudden enlargement (APG) flow. Predictions, of the
mean flow properties and turbulence characteristics of drag reduction turbulent flows
in a sudden enlargement -i.e. under (APG)- are obtained and discussed. An
experimental setup is established for studying the pressure characteristics of the flow
through a (2:1) diameter ratio sudden enlargement test section. The working fluids are
dilute solutions of Polyethylene Glycol (PEG) polymer in tap water. Comparison
between theoretical and experimental pressure distribution results shows a reasonable
agreement. It is concluded that the developed turbulence model can be used to predict
drag reducing polymer flows under both (FPG) and (APG) conditions.