Study on Pressure Characteristics of Fluid Passing through a Sudden Expansion with Central Restriction and Fence

In this paper, a numerical study on pressure characteristics of fluid passing through a configuration of sudden expansion with central restriction only and sudden expansion with central restriction and fence has been carried out. The two dimensional steady differential equations for conservation of mass and momentum are solved for Reynolds number ranging from 50 to 200, percentage of central restriction (CR) from 10% to 40% and for an aspect ratio (AR) from 2 to 6 for both the cases. In addition a fixed fence subtended angle (FSA) of 10 degree with a fixed distance of fence from throat is considered for sudden expansion with central restriction and fence configuration. The effect of each variable on average static pressure distribution, average stagnation pressure drop at a section and wall pressure has been studied in detail. From the average static pressure distribution, it is observed that maximum average static pressure rise increases with increase in Reynolds number and percentage of central restriction for both the configurations. Maximum magnitude of average static pressure rise is achieved at lower aspect ratio. The maximum average static pressure rise is always more in case of fence configuration compared to without fence configuration when all other conditions remain same. The average stagnation pressure drop at a section decreases with increase in Reynolds number and also increase in percentage of central restriction. This pressure drop at a section is less at lower aspect ratio. The average stagnation pressure drop at a section is always less in case of fence configuration compared to without fence configuration when all other conditions remain same. Wall pressure at any section is more for the case of fence configuration compared to the without fence configuration. Keywords— average stagnation pressure, average static pressure, central restriction, Reynolds number, sudden expansion.