2008 Volume 34 Issue 1 Pages 18-24
The local heat transfer and air flow characteristics were experimentally investigated in the wake region formed behind a vertical flat plate in uniform air flow. In the wake region, a dead space in which the air flow velocity was extremely small was formed behind the vertical plate. Near the top edge of the dead space, it was found that the air velocity was increased and a large velocity fluctuation was generated. The heat transfer coefficient was small in the dead space because natural convection mainly occurred. Under suitable conditions, however, the heat transfer was enhanced by almost 50% over that in the absence of the vortex promoter.
From consideration of the heat transfer enhancement, air flow velocity and velocity fluctuation, a correlation equation was proposed for the heat transfer coefficients. Namely, the Nusselt numbers at each position in the wake region were evaluated combination of the Nusselt number for the velocity fluctuation and that in uniform air flow.
