Research Square (Research Square),
Journal Year:
2023,
Volume and Issue:
unknown
Published: June 22, 2023
Abstract
The
relationship
between
entropy
production
and
vortex
evolution
involves
the
efficiency
stability
of
rotating
machinery.
This
study
investigates
energy
characteristics
a
rocket
turbopump,
revealing
correlated
mechanisms
rate
using
dissipation
effects
characteristic
evolution.
Direct
turbulent
dissipations
rigid
shear
vorticity
decomposition
methods
are
utilized
to
analyze
correlation
analysis
flow
loss
vorticities
in
machinery
for
first
time.
With
an
increase
rate,
hydraulic
wall
decrease
by
60%
38.3%,
proportions
input
(from
13%
8%)
remain
stable
(8%),
respectively.
local
direct
(EPDD)
inducer-impeller
is
strongly
related
entropy,
effect
total
enstrophy
on
EPDD
weaker
than
that
vorticity,
indicating
suppresses
dissipation.
significantly
static
passage
turbopump
owing
weak
rotational
effect.
(EPTD)
gradually
increases
with
increasing
reaching
medium
(the
maximal
degree
turbopump)
exhibiting
rotation
loss.
Moreover,
affects
(except
diffuser)
two
reach
maximum
at
designed
optimal
minimum
Physics of Fluids,
Journal Year:
2024,
Volume and Issue:
36(2)
Published: Feb. 1, 2024
The
occurrence
and
development
of
centrifugal
pump
rotating
stall
is
closely
related
to
disturbance
in
the
incoming
flow.
seal
clearance
leakage
an
inherent
impeller
flow
pumps.
In
order
investigate
influence
on
characteristics,
field
numerical
simulation
a
under
conditions
with
without
are
carried
out.
It
found
that
0.4Q0
condition
leakage,
“λ”
special
shaped
high-velocity
region
distribution
along
blade
leading
edges
strengthened,
which
lead
larger
scale
vortices.
And
periodicity
separation
vortex
evolution
more
obvious
leakage.
For
specific
process,
at
initial
format
stage,
there
notable
characteristic
medium
frequencies
band
2–3
times
rotation
frequency
pressure
fluctuation
near
edges,
significantly
different
from
vorticity
analysis
shows
this
induced
Affected
by
disturbance,
propagation
reduced
0.143
rotational
0.103
times.
Meanwhile,
intensity
channels
greatly
enhanced.
Therefore,
judging
frequencies,
regularity,
trend
monitoring
signal,
it
can
not
only
be
used
guide
safe
operation
pumps
off-design
but
also
serve
as
basis
for
wear
seal,
has
important
practical
significance.
Physics of Fluids,
Journal Year:
2023,
Volume and Issue:
35(5)
Published: May 1, 2023
Hydraulic
consistency
between
a
prototype
pump
and
its
hydraulic
model
is
generally
considered
to
be
satisfied,
that
is,
the
energy
performance
flow
structures
conform
similarity
law.
However,
such
may
not
always
exist
in
actual
engineering
projects.
Head
change
vibration
enhancement
large-scale
bulb
tubular
pumps
are
exhibited,
but
reason
for
this
inconsistency
still
unclear.
In
article,
case
study
was
performed
South-to-North
Water
Diversion
Project
China,
pressure
characteristics
impeller
were
explored
under
optimal
condition.
An
interesting
new
phenomenon,
polarization
oscillation,
found.
Its
most
important
feature
constant
difference
average
values
among
axisymmetric
blades,
blades
with
exhibit
large-amplitude
oscillations
around
different
values,
one
revolution
equivalent
rotating
cycle
due
failure
of
consistency.
Further
in-depth
analysis
reveals
realized
by
adjustment
resultant
force
Coriolis
potential
rothalpy
gradient
fluid
motions
sinusoidal
disturbance
gravity,
action
path
presents
hysteresis
loop
rotating.
This
mode
leads
special
conversion
gravity
energy,
kinetic
and,
thus,
hydrostatic
at
initial
phase
cannot
fully
eliminated;
transition
sides
along
against
inconsistent.
finding
suggests
induced
should
if
conventional
applied
pumps.
Journal of Physics Conference Series,
Journal Year:
2024,
Volume and Issue:
2707(1), P. 012136 - 012136
Published: Feb. 1, 2024
Abstract
Rigid
vorticity
transport
equation
is
an
effective
tool
for
describing
the
intuitive
vortex
evolution
characteristics.
Compared
to
single-phase
flows,
curl
of
interphase
force
appears
as
a
new
source
term
this
under
condition
multiphase
which
may
cause
additional
contributions.
However,
effects
interaction
on
rigid
in
water-sand
two-phase
flows
with
fine
particles
are
still
unclear.
In
article,
taking
Karman
vortices
induced
by
hydrofoil
typical
case,
distributions
and
were
compared,
dynamics
mechanism
dominant
was
analyzed.
The
following
notable
results
obtained.
Firstly,
drag
can
be
regarded
force.
Secondly,
effect
tube
mainly
manifested
inducing
normal
strain
contribution
relatively
low.
Thirdly,
there
only
slight
differences
waveform,
amplitude,
frequency
apparent
vortical
structures
between
fine-particle
flows.
These
findings
helpful
understanding
particles.
