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Natural, forced and mixed convection in a vertical cross-corrugated channel Piao, Yinghu
Abstract
Natural, forced and mixed convection heat transfer in a vertical cross-corrugated channel have been experimentally studied, using air as a working fluid. The channel is formed by two transversely positioned corrugated sheets and two flat side-walls which are thermally insulated. The thermal boundary condition is asymmetric and is such that one sheet is radiant-heated and the other is thermally insulated. A hot-wire anemometer and thermocouples were used to measure the fluid velocity and temperature, as well as the wall temperature. The local heat flux across the heated corrugated sheet was also measured with heat flow sensors. In the natural convection experiments, the effect of channel gap on heat transfer was studied. The results show that the Nusselt number NuL based on channel length was larger at the smaller gap than at the larger gap under natural convective flow. This may be due to the specific geometry of the cross-corrugated channel; the boundary layer of the fluid develops from the heated sheet and interacts with the other insulated sheet. For the smaller gap, the interaction of the boundary layer is probably more vigorous compared to the case of the larger gap, which eventually changes the flow pattern and increases the heat transfer. Under forced convection, a heat transfer correlation has been developed and a comparison was made with other similar work. A high heat transfer coefficient in this crosscorrugated channel was achieved with a reasonable value of the friction factor. Local heat transfer rate on the heated corrugated sheet was measured at several different locations with heat flow sensors. The result showed that local heat flux at the valley of the corrugation was less than that at the peak. The ratio of these two heat fluxes was correlated with Reynolds number, and the difference of these two heat fluxes became small as Reynolds number increases in the present experimental range. Mixed convection has been presented in a way which allows comparison to the 'pure' forced convection. Mixed convection in the cross-corrugated channel has shown similar phenomena as buoyancy-aided pipe flow. Natural convection effect on mixed convection was very small in this experimental range.
Item Metadata
Title |
Natural, forced and mixed convection in a vertical cross-corrugated channel
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1992
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Description |
Natural, forced and mixed convection heat transfer in a vertical cross-corrugated channel
have been experimentally studied, using air as a working fluid. The channel is formed by
two transversely positioned corrugated sheets and two flat side-walls which are thermally
insulated. The thermal boundary condition is asymmetric and is such that one sheet is
radiant-heated and the other is thermally insulated. A hot-wire anemometer and thermocouples
were used to measure the fluid velocity and temperature, as well as the wall
temperature. The local heat flux across the heated corrugated sheet was also measured
with heat flow sensors.
In the natural convection experiments, the effect of channel gap on heat transfer was
studied. The results show that the Nusselt number NuL based on channel length was
larger at the smaller gap than at the larger gap under natural convective flow. This may
be due to the specific geometry of the cross-corrugated channel; the boundary layer of
the fluid develops from the heated sheet and interacts with the other insulated sheet.
For the smaller gap, the interaction of the boundary layer is probably more vigorous
compared to the case of the larger gap, which eventually changes the flow pattern and
increases the heat transfer.
Under forced convection, a heat transfer correlation has been developed and a comparison
was made with other similar work. A high heat transfer coefficient in this crosscorrugated
channel was achieved with a reasonable value of the friction factor. Local
heat transfer rate on the heated corrugated sheet was measured at several different locations
with heat flow sensors. The result showed that local heat flux at the valley of
the corrugation was less than that at the peak. The ratio of these two heat fluxes was
correlated with Reynolds number, and the difference of these two heat fluxes became
small as Reynolds number increases in the present experimental range.
Mixed convection has been presented in a way which allows comparison to the 'pure'
forced convection. Mixed convection in the cross-corrugated channel has shown similar
phenomena as buoyancy-aided pipe flow. Natural convection effect on mixed convection
was very small in this experimental range.
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Extent |
1721633 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2008-12-17
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0080921
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1992-11
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.