Thermal Science 2011 Volume 15, Issue 1, Pages: 245-255
https://doi.org/10.2298/TSCI090926044M
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Simulation of turbulent flow and heat transfer over a backward facing step with ribs turbulators
Mushatet Khudheyer S.
Simulation is presented for a backward facing step flow and heat transfer
inside a channel with ribs turbulators. The problem was investigated for
Reynolds numbers up to 32000. The effect of a step height, the number of ribs
and the rib thickness on the flow and thermal field were investigated. The
computed results are presented as streamlines counters, velocity vectors and
graphs of Nusselt number and turbulent kinetic energy variation. A control
volume method employing a staggered grid techniques was imposed to discretize
the governing continuity, full Navier Stockes and energy equations. A
computer program using a SIMPLE algorithm was developed to handle the
considered problem. The effect of turbulence was modeled by using a k-є model
with its wall function formulas. The obtained results show that the strength
and size of the re-circulation zones behind the step are increased with the
increase of contraction ratio(i.e. with the increase of a step height). The
size of recirculation regions and the reattachment length after the ribs are
decreased with increasing of the contraction ratio. Also the results show
that the Reynolds number and contraction ratio have a significant effect on
the variation of turbulent kinetic energy and Nusselt number.
Keywords: backward facing, ribs, turbulent duct flow