The heat transfer characteristics of airflows in serpentine cooling channels in
stator vanes of gas turbines and the novel QuTech® Heat Pipe (QTHP) for electronic
cooling applications were studied. The cooling channels are modeled as smooth and
roughened two-pass trapezoidal channels with a 180° turn over a range of Reynolds
numbers between about 10,000 and 60,000. The naphthalene sublimation technique and
the heat and mass transfer analogy were applied. The results showed that there was a
very large variation of the local heat (mass) transfer distribution in the turn and
downstream of the turn. The local heat (mass) transfer was high near the end wall and
the downstream outer wall in the turn and was relatively low in two regions near the
upstream outer wall and the downstream edge at the tip of the divider wall in the turn.
The variation of the local heat (mass) transfer was larger with ribs on two opposite walls
than with smooth walls. The regional average heat (mass) transfer was lower in the turn
and higher in the entire channel with the flow entering the channel through the larger
straight section than when the flow was reversed. The pressure drop across the turn was higher with the flow entering the channel through the larger channel than when the flow
was reversed.
Thermal performance of the QuTech® Heat Pipe was identified over a range of
inclination angles between 90° and -90° and thermal mechanism of the QTHP was
studied with GC-MS, ICP-OES, XRD, XPS, and DSC. This study resulted in the
following findings: the performance of the QTHP was severely dependent on gravity; the
QTHP utilizes water as working fluid; there were inorganic components such as Na, K, P,
S, and Cr, etc.; and the vaporization temperature of the working fluid (mostly water) was
lower than the boiling temperature of pure water. This was due to the presence of
inorganic salt hydrates in the QTHP. It may be concluded that thermal performance of
heat pipes increases with additional latent heat of fusion energy and energy required to
release water molecules from salt hydrates.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-1940 |
| Date | 02 June 2009 |
| Creators | Lee, Sang Won |
| Contributors | Lau, Sai C., Marotta, Ed |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | electronic, application/pdf, born digital |
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