Influence of flow tree-dimensionality on the heat transfer of a narrow channel backward facing step flows

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Show simple item record Fajardo Peña, Pablo Juste, G.L. 2021-05-05T10:38:57Z 2021-05-05T10:38:57Z 2018-10
dc.identifier.bibliographicCitation Juste, G. & Fajardo, P. (2018). Influence of flow tree-dimensionality on the heat transfer of a narrow channel backward facing step flows. International Journal of Thermal Sciences, vol. 132, pp. 234–248.
dc.identifier.issn 1290-0729
dc.description.abstract This manuscript studies the forced-mixed convective flow on a three-dimensional backward facing step with low aspect ratio (AR = 4) and expansion ratio ER = 2 for Reynolds number in the laminar and beginning of transitional regime (Re 100-1200). The analysis is performed using large eddy simulations, with the main objective assessing the effect of sidewalls on heat transfer characteristics on bottom wall in narrow channels with sudden expansion. The numerical model has been validated with experimental and numerical results from the literature and qualitatively with the experimental results obtained through Moire deflectometry. The bottom surface was kept at constant temperature greater than the flow inlet temperature, while the other walls are considered to be adiabatic. To decouple the three-dimensional flow features due to the sidewalls and the intrinsic three-dimensional instabilities of the separated flow, two different boundary conditions on lateral walls, slip and non-slip, have been used. The results obtained show that when slip sidewalls are considered, the three-dimensional intrinsic structures begging to appear for Re equal to 1200. These structures enhance the heat transfer in the bottom wall. On the contrary, with non-slip sidewalls, the strong three-dimensional structures caused by the sidewalls represented by the upper side recirculation bubble and the wall jets mask the intrinsic three-dimensional instability, decreasing the heat transfer in the lower wall downstream of the step. As a consequence, the surface averaged Nusselt for all Reynolds numbers corresponding to the beginning of the transitional flow is lower for the case of non-slip sidewalls than for the case of slip sidewalls. Thus, the study concludes that sidewalls have a negative effect on heat transfer in narrow channels for flow Reynolds numbers in the early transitional regime.
dc.format.extent 15
dc.language.iso eng
dc.publisher Elsevier
dc.rights © 2018 Elsevier Masson SAS.
dc.rights Atribución-NoComercial-SinDerivadas 3.0 España
dc.subject.other Backward facing step
dc.subject.other Heat transfer
dc.subject.other Narrow channels
dc.subject.other Three-dimensional instabilities
dc.title Influence of flow tree-dimensionality on the heat transfer of a narrow channel backward facing step flows
dc.type article
dc.subject.eciencia Aeronáutica
dc.subject.eciencia Biología y Biomedicina
dc.rights.accessRights openAccess
dc.type.version acceptedVersion
dc.identifier.publicationfirstpage 234
dc.identifier.publicationlastpage 248
dc.identifier.publicationtitle International Journal of Thermal Sciences
dc.identifier.publicationvolume 132
dc.identifier.uxxi AR/0000022129
dc.affiliation.dpto UC3M. Departamento de Ingeniería Aeroespacial
dc.affiliation.grupoinv UC3M. Grupo de Investigación: Ingeniería Aeroespacial
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