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 4.41:
Swirl l Parameter S
Profil les (absolute valu ues)
for L= =8D.
and the en from z7-z13. . The decay inn
the radial veelocity
downsstream
the floow
can be understood fr rom Vr profilles
at z1 and zz7.
At z7 the radial
velocity is
very clo ose to zero and a then at further downnstream
position
z8 it starrts
increasi ing again but with its direction
reversedd
along Xv i.ee.
from z1-z6 thhe
positive e values (vecto or direction nootation)
of Vr are along poositive
Xv and zz8
z11 along g negative Xv. At z12 and z13 Vr is in the same direction
on both siddes
of Xv. Flow F exhibits same behavioor
for Vr at bboth
Reynoldds
numbers ReA
and ReB B.
4.3.4
Swirl Par rameter
Chapter 4
The sw wirl parameter S as definedd
in Chapter 2 is the ratioo
of V to V .
z
Since th he variation in n cylinder lenggth,
in generaal,
has no signiificant
effect oon
the tang gential and ra adial velocity pprofile
at a givven
measuringg
position, onnly
the resu ults for L1 ar re presented here (Figure 4.41). This wwill
provide aan
overview w of local swirl
distributionn
as well as thee
decay in thee
swirl along thhe
flow dir rection for ReA A and ReB.
To get a better overv view of swirl parameter aloong
the cylindder,
figure 4.442
gives th he profile of f S whichh
is the maxximum
value of local swiirl
max
parame eter for a given
measuring position. Proffile
generally demonstratess
a
sharp li inear like deca ay in swirl fromm
z1-z4 and then
a very small.
The linear ffit
has a slo ope of 1.7732 and a Y-axis intercept
of -0. .52964. For L33
at z6 a increaase
in S is observed which, w as descrribed
before, iss
due to the efffect
of cylindder
max
93
Swirling Flow in a Pipe