Numerical investigation and analysis of heat transfer enhancement in channel by longitudinal vortex based on field synergy principle |
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Authors: | Wenquan TAO Junmei WU |
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Affiliation: | (1) State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, 710049, China;(2) School of Environment and Chemical Engineering, Xi’an Polytechnic University, Xi’an, 710048, China |
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Abstract: | 3-D numerical simulations were presented for laminar flow and heat transfer characteristics in a rectangular channel with
vortex generators. The effects of Reynolds number (from 800 to 3 000), the attack angle of vortex generator (from 15° to 90°)
and the shape of vortex generator were examined. The numerical results were analyzed based on the field synergy principle.
It is found that the inherent mechanism of the heat transfer enhancement by longitudinal vortex can be explained by the field
synergy principle, that is, the second flow generated by vortex generators results in the reduction of the intersection angle
between the velocity and fluid temperature gradient. The longitudinal vortex improves the field synergy of the large downstream
region of longitudinal vortex generator (LVG) and the region near (LVG); however, transverse vortex only improves the synergy
of the region near vortex generator. Thus, longitudinal vortex can enhance the integral heat transfer of the flow field, while
transverse vortex can only enhance the local heat transfer. The synergy angle decreases with the increase of Reynolds number
for the channel with LVG to differ from the result obtained from the plain channel, and the triangle winglet performs better
than the rectanglar one under the same surface area condition.
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Translated from Journal of Xi’an Jiaotong University, 2006, 40(9): 996–1000 译自: 西安交通大学学报] |
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Keywords: | longitudinal vortex heat transfer enhancement field synergy principle |
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