JP Journal of Heat and Mass Transfer
Volume 1, Issue 1, Pages 27 - 48
(February 2007)
|
|
EXPERIMENTAL
INVESTIGATION ON MIXED CONVECTION IN A
HORIZONTAL
PARALLEL-PLATE CHANNEL
HEATED FROM BELOW
Giuseppe Foglia (Italy), Stefano Lazzari (Italy) and Oronzio Manca (Italy)
|
Abstract: In this paper, mixed convection in a horizontal channel, with
the lower wall heated at uniform heat flux is studied experimentally. The upper
wall is unheated and allows a heat transfer with the external ambient. The
experiments are performed with air as working fluid. The investigated Reynolds
numbers (Re) are between 5.0 and 1000 and the Rayleigh (Ra) number ranges from
to
The effect of the secondary motion along the heated wall of the channel is
detected by measuring the lower wall temperatures along the longitudinal axis
for
and by flow visualization for
Results show that the separation from the lower heated wall strongly depends on
the buoyancy force and forced velocity. In fact, at lower Reynolds numbers the
higher the wall heat flux, the smaller the axial coordinate where the flow
separation takes place. Different flow structures due to secondary motions are
observed. Correlations for average Nusselt number and for separation point as a
function of Richardson and Grashof numbers are proposed in the ranges
and
|
Keywords and phrases: mixed convection, horizontal parallel plate channel, experimental investigation, flow visualization, heat transfer correlation. |
|
Number of Downloads: 244 | Number of Views: 889 |
|