Thermal Science 2012 Volume 16, Issue 1, Pages: 53-67
https://doi.org/10.2298/TSCI101120080T
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Numerical study of the conjugate heat transfer in a horizontal pipe heated by Joulean effect
Touahri Sofiane (Physic Energetic laboratory, Department of Physic Faculty of Sciences, Mentouri University, Constantine, Algeria)
Boufendi Toufik (Physic Energetic laboratory, Department of Physic Faculty of Sciences, Mentouri University, Constantine, Algeria)
The three dimensional mixed convection heat transfer in a electrically heated
horizontal pipe conjugated to a thermal conduction through the entire solid
thickness is investigated by taking into account the thermal dependence of
the physical properties of the fluid and the outer heat losses. The model
equations of continuity, momentum and energy are numerically solved by the
finite volume method. The pipe thickness, the Prandtl and the Reynolds
numbers are fixed while the Grashof number is varied from 104to107. The
results obtained show that the dynamic and thermal fields for mixed
convection are qualitatively and quantitatively different from those of
forced convection, and the local Nusselt number at the interface solid-fluid
is not uniform: it has considerable axial and azimuthally variations. The
effect of physical variables of the fluid depending on temperature is
significant, which justifies its inclusion. The heat transfer is quantified
by the local and average Nusselt numbers. We found that the average Nusselt
number of solid-fluid interface of the duct increases with the increase of
Grashof number. We have equally found out that the heat transfer is improved
thanks to the consideration of the thermo dependence of the physical
properties. We have tried modelling the average Nusselt number as a function
of Richardson number. With the parameters used, the heat transfer is
quantified by the correlation: NuA=12.0753 Ri0.156
Keywords: mixed convection, cylindrical pipe, conjugate heat transfer, finite volume method.