Experimental and Numerical Study of Swirling ... - Solid Mechanics
Experimental and Numerical Study of Swirling ... - Solid Mechanics
Experimental and Numerical Study of Swirling ... - Solid Mechanics
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Experi imental <strong>and</strong> <strong>Numerical</strong> N Stud dy <strong>of</strong> <strong>Swirling</strong> g Flow in Scaveenging<br />
Processs<br />
for 2-Stroke<br />
Marin ne Diesel Engin nes<br />
Figure<br />
5.23:<br />
Resulta ant <strong>of</strong> Normalize ed<br />
in-plan ne Reynolds<br />
Norma al Stress<br />
Compo onents<br />
(<br />
) @ z1<br />
<strong>and</strong> 75 5% port closure.<br />
Chapter 5<br />
vrv r at a z is low in the near wall region <strong>and</strong> inncreases<br />
to its peak value att<br />
a<br />
1<br />
radial position p r/R=0.5<br />
<strong>and</strong> the agaain<br />
decreases ttowards<br />
the cyylinder<br />
axis. Foor<br />
v v the t value is also<br />
low at the near wall reggion<br />
<strong>and</strong> increease<br />
towards thhe<br />
cylinder<br />
axis.<br />
At z th he uu <strong>and</strong><br />
v vhave v two pairs <strong>of</strong> orthoogonal<br />
zones with each paair<br />
2<br />
having the high <strong>and</strong> low l values resspectively<br />
(Figgure<br />
5.24). Thee<br />
zones pairs aare<br />
at large e radial distanc ce from cylindder<br />
axis. For u uuthe pair wwith<br />
high valuues<br />
are alon ng X-axis <strong>and</strong> d for vv alonng<br />
Y-axis. This<br />
will add-up to give highher<br />
values in i cylinder cen nter region annd<br />
low values in the near wwall<br />
regions. Thhe<br />
ww is<br />
still the dom minant compoonent.<br />
The peaak<br />
value is redduced<br />
to a smaall<br />
extent compared c to z . Spatial disttribution<br />
is annisotropic<br />
<strong>and</strong>d<br />
has low valuues<br />
1<br />
in the vortex v core an nd near wall reegion<br />
<strong>and</strong> peaak<br />
values in thhe<br />
intermediaate<br />
region.<br />
At z th he spatial distr ribution <strong>of</strong> v vv 2 <strong>and</strong> vv r v r is oppositee<br />
to each otheer.<br />
i.e. the fluctuations in the radial direction vv r v r are large at larger radiial<br />
distance es <strong>and</strong> decreas ses towards thhe<br />
cylinder axxis.<br />
Whereas inn<br />
case <strong>of</strong> vv v <br />
the tan ngential veloci ity fluctuationns<br />
are low att<br />
larger radial<br />
distances annd<br />
increase es towards the e cylinder axis. .<br />
Despite e a large increa ase in the maggnitude<br />
<strong>of</strong> normal<br />
stress coomponents<br />
at z , 1<br />
the valu ues at z do not<br />
increase in thhe<br />
same orderr<br />
compared to fully open poort<br />
6<br />
(see Ap ppendix B). Th his indicates tthat<br />
the downnstream<br />
decayy<br />
in the velociity<br />
fluctuat tions also incr reases with thhe<br />
increase in partial closurre<br />
<strong>of</strong> the intakke<br />
port. This<br />
may be th he upstream iinfluence<br />
or iin<br />
other wordds<br />
the dampinng<br />
effect <strong>of</strong><br />
the outlet co ontraction on tthe<br />
in-cylinderr<br />
flow.<br />
130<br />
Effect <strong>of</strong> Piston Position
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