Analysis of performance characteristics of S-shaped diffuser with offset

Abstract

This paper presents the effect of offset (i.e. inlet and outlet are in two different planes) on S-shaped diffuser of 90°/90°turn with rectangular inlet ( AS = 2 ) and semicircular outlet ( AR = 2 ). A computer program based on finite volume technique, using standard k – ε 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 0.3125 D 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.