Fluid flow and heat transfer characteristics
around a semi-circular tube in cross flow were experimentally
and numerically investigated. Three different
tube-flow arrangements were considered. Firstly, the
flat surface of the tube was placed parallel to the
freestream flow; secondly, the flat surface of the tube
was facing the upstream flow and thirdly, the curved
surface of the tube was facing the upstream flow. For
the second and the third arrangements, different angles
of attack were studied. Flow visualization was carried
out to illustrate streamlines around the tube and to
verify flow patterns obtained from the numerical calculations.
It was found that: (1) for any angle of attack,
the arrangement of the curved surface facing the flow
gave higher average Nusselt number than the
arrangement of the flat surface facing the flow and (2)
for all tube-flow arrangements, increasing the angle of
attack slightly increases the average Nusselt number.
Correlations of Nusselt numbers in terms of Reynolds
number and angle of attack were deduced from the
experimental results for the three arrangements. The
comparisons between the experimental data, correlations’
predictions and numerical results showed reasonable
agreements |
