Validated Numerical Simulations Investigating the Effects of Cross-sectional Asymmetry on Fluid Flow and Heat Transfer

Abstract

The work documented in this thesis focuses on numerical analysis as the primary means of gaining insight into the behavior of fluid flow and associated heat transfer in a situation where some kind of cross-sectional asymmetry has been introduced in the flow. As such, results from numerical experiments validating experimental data in asymmetric flow around pipe bends are presented near the beginning of this work. Thereafter, the results of numerical investigation into three situations have been presented. The first involves analyzing fluid flow in a piezometer ring, a device widely used to measure pressure in pipes, where the flow is cross-sectionally asymmetric due to the ring being present right after a 90° bend. The results from this chapter include recommendations for tap-off angles in a piezometer ring and the relative diameters of the ring and the tubes connecting it to the main pipe. The second situation involves numerical analysis of a rectangular fluid jet switching axes before impinging on a flat plate. The switching of axes in rectangular jets is a commonly observed asymmetry in fluid flow that is seldom investigated numerically due to very high computational cost. The results from this chapter present correlations that accurately predict experimental data on heat transfer from plate center, and graphs and figures that demonstrate the off-centered position of the areas of highest heat transfer on the plate. The third and final situation involves numerically analyzing 90° pipe bends of varying radii of curvature, fitted with orifices of varying blockage positioned at the start of the bend, for effects on heat transfer from the portion of the pipe past the bend. The effect of both the bend and the orifice is to introduce asymmetry in the flow and the results presented demonstrate the relative influence of the orifice and the bend radii on fluid flow and heat transfer from the straight section of the pipe after the bend.