Experimental and Numerical Study of Swirling ... - Solid Mechanics

Experi imental and Numerical N Stud dy of Swirling g Flow in Scaveenging
Processs
for 2-Stroke
Marin ne Diesel Engin nes
Figu ure 6.8:
Comp parison of
Norm malized Tangentia al
Veloci ity Profile at z . 6
Figu ure 6.9:
Comp parison of
Norm malized Axial
Veloc city Profile at z . 1
6.2.2
Axial Ve elocity
Chapter 6
For nor rmalized axial l velocity proffiles,
at z , all the simulatioon
cases resultt
a
1
wake-lik ke profile but
with a recirrculation
zonne
in the vorttex
core regioon
(Figure 6.9). This see ems to be a mmajor
differencce
between thhe
experimenttal
and num merical results s because the experimental data, at z doees
not show anny
1
recircul lation. Since no n measuremeents
have beenn
carried out at
cross sectionnal
position ns before z , it t is however unnknown
whetther
or not in the experiment
1
setup th here exists an ny recirculation
prior to z . The vortex ccore
size is also
1
predicte ed to be larg ger than the experimentaal
data. This shows a pooor
agreement
with the experimentall
data. RNG k modell
with T.I 100%
predicts s a comparativ vely lower peaak
axial velociity
magnitudee
than the othher
simulat tion cases. All
the modells
show reasoonable
agreemment
with thhe
experim mental axial ve elocity profile in the region close to the wwall
i.e X/R =00.6
to 0.8.
154
Numerical Modeling