Heat transfer and fluid mechanical behavior of water
flowing horizontally in vertically-narrow rectangular
channels was studied in this work. Friction factor and
Nusselt number variations were determined experimentally
for four different wall heating conditions, and for aspect
ratios(height to width) of 5, 4, 3, 2, and 1. Wall
heating conditions examined were: all surfaces heated;
three surfaces heated, the top adiabatic; one side surface
heated the others adiabatic; and the bottom surface
heated, the others adiabatic.
Friction factors, in laminar flow, varied as
predicted from analysis. The critical Reynolds number
varied linearly with 1n(D[subscript]).
Local Nusselt numbers were determined, at each aspect
ratio and heating condition, as functions of Reynolds and
Rayleigh numbers. Mixed convection was the result of
buoyancy-induced secondary flows. Local Nusselt numbers
decreased in a manner common to pure forced convection,
reaching minimum values some distance from the entrance,
then increased due to the presence of the secondary flows.
For given aspect ratio, local Nusselt numbers were found
to increase and the thermal entrance lengths decreased,
with increasing Rayleigh numbers. In the thermal entry
region, for all heating conditions except the bottom-heating
case, local Nusselt number behavior showed minor
dependence on aspect ratio. / Graduation date: 1999
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/33486 |
| Date | 21 September 1998 |
| Creators | Hong, Seung-Ho |
| Contributors | Welty, James R. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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