Numerical studies on fluid flow characteristics through different configurations of spiral casing. Issue 1 (1st January 2016)

• Record Type: Journal Article
• Authors: Nakkina, Parameswara Rao; Arul Prakash, K.; Saravana Kumar, G.
• Is Part Of: Engineering applications of computational fluid mechanics. Volume 10:Issue 1(2016)
• Page Start: 296
• Page End: 310
• Publication Date: 2016-01-01
• Subjects: Spiral casing -- elliptical cross-section -- finite-element method -- spiral velocity coefficient; Computational fluid dynamics -- Periodicals; 620.10640285
• DOI: 10.1080/19942060.2016.1149103
• Languages: English
• ISSNs: 1994-2060

Abstract

ABSTRACT: The design of optimum spiral casing configuration is a difficult task and a big challenge in the field of turbomachinery. Computational fluid dynamics (CFD) analysis of fluid flow characteristics in a turn around spiral casing plays an important role in its design. The objective in this study is to propose an optimum spiral casing configuration by reducing the total pressure loss and increasing the spiral velocity coefficient and average radial velocity at the exit of spiral casing. For this, three different configurations of spiral casing, viz. accelerated, decelerated and free vortex type, with different aspect ratios ( AR s) are numerically simulated. A Eulerian velocity-correction method based on the streamline upwind Petrov–Galerkin (SUPG) finite-element method is employed to solve complete Reynolds-averaged Navier–Stokes (RANS) equations governing fluid flow characteristics. The results show that the average radial velocity along the exit of spiral casings is more for elliptical cross-sectional spiral casings of AR >1 when compared to circular cross-sectional spiral casings. The total pressure loss is found to be at minimum for decelerated spiral casings. In the case of decelerated spiral casings, a further reduction in total pressure loss is obtained with elliptical cross-sections of AR >1. The spiral velocity coefficient is found to be at maximum for decelerated spiral casings with AR >1.