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Memorias de investigación
Research Publications in journals:
Influence of flow tree-dimensionality on the heat transfer of a narrow channel backward facing step flows
Year:2018
Research Areas
  • Mechanical aeronautics and naval engineering
Information
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 Moiré 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.
International
Si
JCR
Si
Title
International Journal of Thermal Sciences
ISBN
1290-0729
Impact factor JCR
3,361
Impact info
Datos JCR del año 2017
Volume
132
10.1016/j.ijthermalsci.2018.06.005
Journal number
From page
234
To page
248
Month
SIN MES
Ranking
Participants
  • Autor: Gregorio Lopez Juste (UPM)
  • Autor: Pablo Fajardo (Universidad Carlos III de Madrid)
Research Group, Departaments and Institutes related
  • Creador: Departamento: Mecánica de Fluidos y Propulsión Aeroespacial
S2i 2020 Observatorio de investigación @ UPM con la colaboración del Consejo Social UPM
Cofinanciación del MINECO en el marco del Programa INNCIDE 2011 (OTR-2011-0236)
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