Flow and Performance Characteristics of S- Shaped Diffuser

Abstract

This paper presents the effect of turning angle on the first and second curvature of S-shaped diffusers, one with a square inlet and rectangular outlet having a centre length of 800 mm and an area ratio of 2.5. A computer program based on the finite volume technique, using the Standard k–ε turbulence model, has been adopted and modified to predict the flow. The measurements of pressure distributions of the airflow in S-shaped diffusers are performed for twelve models of different turn angles such as 30º/30º, 60º/ 60º, 90º/ 90º, 120º/ 120º, 150º/ 150º, 180º/ 180º, 60º/90º, 90º/ 60º, 90º/ 120º, 120º/ 90º, 120º/ 150º, 150º/ 120º. In this paper, results are shown in the form of pressure recovery coefficient and pressure recovery efficiency. Furthermore, pressure and velocity contours have been developed for the entire study of all twelve designs of the diffuser. The results showed that the diffuser pressure recovery coefficient is strongly affected by the geometrical parameters of the S-shaped diffuser and inflow Reynolds number. The turning angle plays an important role in improving the S-shaped diffuser's performance. In this study it is concluded that diffuser 90º/ 120º performs best, it gives the highest pressure recovery coefficient and efficiency, whereas diffuser 30º/30º gives the lowest performance parameters.