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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Three-Dimensional Computational Study of Natural Convection in a Non-Uniformly Heated Vertical Open-Ended Channel

Get access (open in a dialog) DOI: 10.1615/IHTC15.ncv.009046
pages 5359-5370

Sinopsis

An improved understanding of the flow and heat transfer phenomena in a narrow channel formed by a double skin façade on a building in order to enhance the cooling of the PV cells is described in this paper. To simulate the actual configuration, uniformly heated strips (representing the PV arrays) alternating with unheated strips (windows in the solid building wall) have been included in the model. Most of the studies on natural convection within channels focus on laminar or fully turbulent flows, since transition from laminar to turbulent flow is difficult to identify and to control. However, transition to turbulence plays a key role since turbulence produces flow structures responsible for high levels of mixing and thus increased heat transfer. To understand the flow behaviour and possible transition from the laminar to turbulent regimes in this complex non-uniform heating configuration, the three-dimensional flow in the channel was simulated. A number of flow structures were identified. Vortices in the corners of the channel promote horizontal convection, transferring heat from the panels to the lateral walls. The recirculation zone caused by the unheated area at the entrance of the channel contributes to the periodicity of flow within the channel, enhances the mixing and changes the frequencies of fluctuations in the temperature and velocity along the wall; it also contributes to lower average temperatures and amplitudes of temperature fluctuations. In general, it has been shown that the disturbances introduced at the inlet of the system improve the mixing and heat transfer.