Publication Date

2022

Document Type

Dissertation/Thesis

First Advisor

Shelton, John

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Mechanical Engineering

Abstract

Computational fluid dynamics (CFD) and discrete element method (DEM) are powerful tools for simulating systems that contain fluids and particles. Studies of particle fluid systems greatly vary in their applications and complexity, and yet there is a scarcity of studies focused on the thermal characteristics of the fluid. A computational analysis is conducted on two-dimensional flow in a square thermal lid-driven cavity to assess the effect of particle suspensions on the thermal characteristics of the cavity. Most studies analyzing the effect of suspensions in a thermal lid-driven cavity treat the medium as a single homogeneous nanofluid. Those that do treat suspensions as individual particles do not include a temperature component. In this work, the cavity lid generates forced convection in a clockwise direction, while the two side walls are kept at different temperatures to generate natural convection in a counterclockwise direction, and dominant regime is determined by the direction of the resulting primary vortex. The centerline velocities, minimum stream functions, centerline temperatures, and boundary layer thickness along the hot wall are evaluated in each study. These are conducted for Reynolds numbers of 100, 400, and 1000, as well as temperature differences of 50, 100, and 150 between the thermal boundaries, and particle area fractions of 10%, 20%, and 30%. In the case of the thermal lid-driven cavity with no particles, forced convection is the dominant flow regime, but the magnitude of the stream function decreased as the temperature difference between walls increased. This temperature difference had no effect at all on the boundary layer profile along the hot wall. Preliminary studies of the thermal LDC with particle suspensions show very little conductive heat transfer between particles and the cavity walls when they collide. For the isothermal particle laden cavity, the particle area fraction did not significantly affect the boundary layer profile. The computational software used in this study does not have a solver capable that includes both a temperature component and particles, and can only simulate them individually. While some progress has been made on this front, a complete analysis of a thermal particle laden cavity could not be done in the time available. Attempts were made to approximate the thermal characteristics of the cavity by applying the results of the thermal LDC to the isothermal lid-driven cavity with particles. However, no relationship could be found between average Nusselt number of the hot boundary and the minimum stream function, meaning that the strength of the primary vortex could be used to predict a cavity’s heat transfer characteristics. In order to assess in how the presence of particles affects heat transfer, more simulations of an LDC incorporating both a temperature component and particle suspensions, are still ongoing.

Extent

86 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

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