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Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School

Mechanical Engineering

First Advisor

A. Moutsoglou


A computational analysis is conducted to investigate the three dimensional heat transfer and flow characteristics of laminar natural convection in a vertical duct open to the ambient at the top and bottom and enclosed on all four sides. Detailed data are presented for air (Pr=0.7) in a square duct heated or cooled on one side with the remaining three walls assumed adiabatic. Results for both uniform wall temperature and uniform heat flux surface conditions are discussed in the study. Corresponding numerical data is also obtained and presented for comparisons via the two-dimensional channel flow approximation. The channel flow model that neglects the slowing down of the streamwise velocities due to the friction of the lateral walls predicts higher local and average Nusselt numbers than those estimated by a three dimensional analysis for a duct. Comparisons are also made with data of a single heated or cooled plate immersed in an ambient quiescent fluid. Duct cross-sectional aspect ratio effects on heat transfer rates are also investigated in the study. The numerically predicted data for a duct heated isothermally on two opposing sides and having two adiabatic lateral edges are compared to the experimental data of Sparrow and Bahrami [8].

Library of Congress Subject Headings

Heat -- Convection, Natural
Air ducts -- Aerodynamics
Heat -- Transmission



Number of Pages



South Dakota State University