碩士 / 元智工學院 / 機械工程學系 / 84 / In the present study, fifteen samples of plate fin heat
exchangers with different geometrical parameters, including
number of tube rows, fin spacing, and fin thickness are tested.
The experiments were carried out in two tunnels with various
operating conditions. One is an open-type induced-flow wind
tunnel under dry operating conditions. The other is a forced
circulation wind tunnel under dehumidifying conditions. Results
are presented in the form of friction factor f and Colbun j
factor against Reynolds number based on tube collar diameter in
the range of 300 to 7500. Under dry conditions, the variation of
the fin spacings does not affect the heat transfer coefficient;
the effect of the number of tube rows on the friction factor is
negligible;and the fin thickness have no obvious effect on the
heat transfer and friction characteristics. Correlations based
on experimental data are proposed that can describe 97﹪ of j
and 88﹪of f data within 10﹪. Under dehumidifying conditions,
nine plate fin heat exchangers were investigated. The effect of
fin spacings, number of tube row and inlet conditions were
investigated. It is found that the inconsistency with the
reported data in the open literature may be associated with the
wet fin efficiency. A correlation is proposed for the data of
the present plate fin configurations, this correlation can
describe 91﹪of j and 92﹪of the f data within 10﹪. Besides,
two louver fin heat exchangers were tested under both dry and
wet operating conditions. One of the heat exchangers is treated
with hydrophilic coating and the other has uncoated fin
surfaces. Experimental data show that the coating reduces
friction factors about 10 to 20﹪under wet operating conditions.
| Identifer | oai:union.ndltd.org:TW/084YZU00489016 |
| Creators | Hsieh, Yi Chung, 解怡中 |
| Contributors | Y.T. Lin, 林育才 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 69 |
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