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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

PROCEEDINGS FULL PAPER MULTIPLICITY OF NANOFLUID FORCED CONVECTION HEAT TRANSFER IN CURVED DUCTS

Get access (open in a dialog) DOI: 10.1615/IHTC16.cov.021819
pages 3231-3238

Resumo

In the present work, a numerical study is made on the laminar fully-developed forced convective heat transfer of nanofluids in a curved square duct using Eulerian-Lagrangian two-phase approach. The curvature ratio of the duct is 0.02 and its hydraulic diameter is 8 mm. The Al2O3-water nanofluids contain spherical nanoparticles with particle diameter of 30 nm and volume fraction of 0.5%. Multiple flow structures are obtained using three different computers at the same conditions, which may be due to the random disturbances generated by different computers. Three different flow fields are symmetric at De of 169.7 and asymmetric at De of 335.2, and result in multiple non-uniform nanoparticle concentration distributions and multiple temperature fields. The multiple flow structures and temperature fields lead to multiple symmetric (asymmetric) local Nusselt number and symmetric (asymmetric) local friction factor along the outer wall at De of 169.7 (335.2), and finally lead to multiple mean friction factor and multiple mean Nusselt number. A significant enhancement of heat transfer (e.g. 23.79%) can be achieved at the expense of a slight increase of flow friction (e.g. 6.84%), in the square curved ducts. This study could provide an explanation, from a new respect, for the inconsistent results of convective heat transfer of nanofluid in the literature.