Abstract:
Detached-Eddy-Simulations (DES) were performed for
investigating the thermal-hydraulics of a one-sided heated and
rib-roughened cooling channel at Reynolds numbers ranging
from 2.5·104 to 1.58·105. Heat transfer and flow characteristics
for three different types of centrally positioned, transversally
oriented rib-elements with a rib-height and rib-top-width of e
and (a) 90 deg. edged, (b) 2 e radius round-edged or (c) 30 deg.
inclined front- and rear-rib-surface haven been analyzed. The
channel cross section was 15 e x 15 e with 2 e inside radiuses,
the rib-pitch-to-rib-height-ratio was p/e = 10 and the rib-heightto-
hydraulic-diameter-ratio was e/Dh = 0.0638. For all
simulations, friction factors decrease and heat transfer
coefficients increase for increasing Reynolds numbers. For
varying rib-shapes, the averaged friction factor ratios differ up
to 30 pct. and the Nusslet Numbers at the rib-roughened and the
overall Nusselt Numbers differ up to 12 pct. and 8 pct.,
respectively. Maximum flow resistance and heat transfer occur
for the 90 deg. edged rib-configuration. For all rib-shapes, the
thermal performance factor (of increased heat conductance and
equal pumping power) for cooling the rib-roughened wall
decreases for increasing Reynolds numbers. Best thermal
performance was obtained for the 90 deg. edged ribconfiguration.
Correlations for Nusselt number and average
friction factor prediction were derived for the entire Reynolds
number range.
Description:
Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016.
