Mesh Twisting Technique for Swirl Induced Laminar Flow Used to Determine a Desired Blade Shape

Abstract

Swirling flow has been shown to increase heat transfer in heat exchangers. However, producing swirl while not presenting a severe pressure drop can be a challenge. In this paper, a desired shape of guidance blades for laminar swirl flow is determined by numerical simulation in OpenFOAM. Emphasis is on the mesh technique, where a predefined blade shape is formed by mesh twisting, or morphing. The validity of numerical simulations on a twisted mesh is shown by comparing it to the theoretical solution of laminar flow in a pipe without swirl and guidance blades. A sensitivity study shows that a cell size ratio of 0.025 of diameter is sufficient and affects the solution minimally. To determine the desired shape of guidance blades previously found optimal swirl decay and velocity profile for laminar swirling flow are utilized. Three blade shapes are explored: (I) with a twist angle that varies with axial location only; (II) having a deviation angle matching the theoretical deviation angle for laminar swirling flow; (III) same as II but with a hollow center. Simulations are performed for Re = 100 and swirl number S = 0.2 . Case II is able to sustain swirl longest while maintaining a low pressure drop and is therefore a desired swirler shape profile as predicted theoretically.

The Development of Current Collection in Micro-Tubular Solid Oxide Fuel Cells—A Review

“…Materials inside the tube bore such as brushes, coil meshes and foam types will certainly impact on the fluid flow, causing turbulence and better mixing at the expense of an increase in pressure drop [130]. The aforementioned will likely enhance heat transfer within the cell, primarily from convection but also conduction when contacted to the wall [131].…”

Comparison of The Flow Characteristics between Circular and Wedged Configurations in Internal Combustion Engine Chambers

“…The swirl number is defined by the angular momentum axial flux divided by the axial momentum axial flux [19] (5)…”

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