Thermal Science 2016 Volume 20, Issue suppl. 1, Pages: 47-57
https://doi.org/10.2298/TSCI151130016X
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A computational study of heat transfer under twin turbulent slot jets impinging on planar smooth and rough surfaces
Xu Peng (China Jiliang University, College of Science, Hangzhou, China + McGill University, Department of Mining and Materials Engineering, Montreal, Canada)
Sasmito Agus P. (McGill University, Department of Mining and Materials Engineering, Montreal, Canada)
Mujumdar Arun S. (McGill University, Department of Mining and Materials Engineering, Montreal, Canada)
The flow and heat transfer characteristics of twin turbulent slot jets
impinging on planar smooth and rough surfaces are examined using a
computational fluid dynamics model. The interaction between jets lowers the
heat transfer performance of each jet in the zone where the wall jets
collide. A single jet performs better than the equivalent twin jet. The
average heat transfer under twin jets which are injected alternately so that
each one of the pair of jets behaves like a single jet, is found to be better
than twin jets issuing simultaneously. It is proposed that alternating jet
flows in the twin jet arrangement is a simple novel way to enhance thermal
performance of jet pairs. Along with parametric studies of the key flow and
geometric parameters, effects of large temperature differences between the
jet air and the target surface being heated, and model roughness of the
target surface are also evaluated. Interestingly, roughness can lower the
heat transfer performance in the impingement zone as the fluid can get
trapped in the valleys in the rough surface.
Keywords: gas impingement, twin jets, surface roughness, alternating flows, CFD