Analysis of performance characteristics of S-shaped diffuser with offset

This paper presents the effect of offset (i.e. inlet and outlet are in two different planes) on S-shaped diffuser of 90 degrees/90 degrees turn with rectangular inlet (AS = 2) and semicircular outlet (AR = 2). A computer program based on finite volume technique, using standard k-s turbulence model, has been adopted and modified to predict the flow. The obtained results from this research show reduced outlet pressure recovery accompanied with increase in non-uniformity at the exit due to offset. This paper also shows that increase in Reynolds number has marginal effect on the outlet pressure recovery for zero offset and 0.3125D cases and similar results have been found for other offset cases which have not been presented in the paper to avoid repeatability. The present S-duct geometry fulfills only pressure recovery requirement, and hence needed modification to improve the uniformity at the exit. (c) 2006 Elsevier Masson SAS. All rights reserved.