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

Fajardo Peña, Pablo; Juste, G.L.

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

dc.affiliation.dpto	UC3M. Departamento de Ingeniería Aeroespacial	es
dc.affiliation.grupoinv	UC3M. Grupo de Investigación: Ingeniería Aeroespacial	es
dc.contributor.author	Fajardo Peña, Pablo
dc.contributor.author	Juste, G.L.
dc.date.accessioned	2021-05-05T10:38:57Z
dc.date.available	2021-05-05T10:38:57Z
dc.date.issued	2018-10
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.	en
dc.format.extent	15
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.	en
dc.identifier.doi	https://doi.org/10.1016/j.ijthermalsci.2018.06.005
dc.identifier.issn	1290-0729
dc.identifier.publicationfirstpage	234
dc.identifier.publicationlastpage	248
dc.identifier.publicationtitle	International Journal of Thermal Sciences	en
dc.identifier.publicationvolume	132
dc.identifier.uri	https://hdl.handle.net/10016/32538
dc.identifier.uxxi	AR/0000022129
dc.language.iso	eng
dc.publisher	Elsevier	en
dc.rights	© 2018 Elsevier Masson SAS.	en
dc.rights	Atribución-NoComercial-SinDerivadas 3.0 España	*
dc.rights.accessRights	open access
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/es/	*
dc.subject.eciencia	Aeronáutica	es
dc.subject.eciencia	Biología y Biomedicina	es
dc.subject.other	Backward facing step	en
dc.subject.other	Heat transfer	en
dc.subject.other	Narrow channels	en
dc.subject.other	Three-dimensional instabilities	en
dc.title	Influence of flow tree-dimensionality on the heat transfer of a narrow channel backward facing step flows	en
dc.type	research article	*
dc.type.hasVersion	AM	*
dspace.entity.type	Publication