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Flow pulsation and baffle’s effects on the opposing mixed convection in a vertical channel. (English) Zbl 1188.76247
Summary: This numerical study aims to investigate the effects of a horizontal baffle on the heat transfer characteristics of pulsating opposing mixed convection in a parallel vertical open channel. The influences of the dimensionless pulsating frequency Strouhal number and magnitude \(A\), Prandtl number and baffle position \(L_{b}\) on the velocity and temperature distribution and long-time average Nusselt number \(\langle \overline {Nu}\rangle \) variation for the system at various \(Re\) and \(Gr/Re^{2}\) are explored in detail. Our results show that the channel with both flow pulsation and a baffle gives the best heat transfer. With a larger \(Re\), the inlet flow pulsation dominates the whole velocity field in the channel. \(\langle \overline {Nu}\rangle \) always increases with a larger \(Re\), pulsation magnitude \(A\) and Prandtl number. Maximum \(\langle \overline {Nu}\rangle \) occurs at some specific imposed pulsating frequencies which can be considered to be the natural frequency of the system.

MSC:
76R05 Forced convection
76R10 Free convection
76M20 Finite difference methods applied to problems in fluid mechanics
80A20 Heat and mass transfer, heat flow (MSC2010)
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