Electronic Thesis and Dissertation Repository

Degree

Master of Engineering Science

Program

Mechanical and Materials Engineering

Supervisor

Dr. J. M. Floryan

Abstract

A technique has been proposed to increase flow mixing in annuli by means of vortex generation. Corrugations in the form of axisymmetric ribs are placed at the walls of annulus to modulate the axial flow which can potentially induce vortex instabilities. Unlike other vortex generation methods which suffer from relatively high pressure losses, this technique is expected to cause less pressure drop. Spectral algorithm based on Fourier and Chebyshev expansions has been used to study the stationary state and its stability. Due to the irregularities of the boundaries, the immersed boundary conditions (IBC) method is used to enforce the flow boundary conditions. The effect of geometric and flow parameters on pressure losses and stability have been thoroughly investigated. Characteristics of vortex mode and travelling wave instabilities as well as region of dominance in each case are also determined. Moreover, it has been shown that effect of arbitrary ribs can be accurately captured using reduced geometry model.


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