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
Journal of Physics Conference Series,
Journal Year:
2024,
Volume and Issue:
2707(1), P. 012022 - 012022
Published: Feb. 1, 2024
Abstract
The
guide-vane
cone
diffusion
is
a
typical
structural
difference
between
an
axial-flow
pump
and
tubular
pump,
which
shown
as
low
diffusivity
high
respectively,
but
it
still
unclear
how
this
affects
the
vortex
characteristics
in
stator
corner
separation
flows.
In
paper,
comparative
study
of
flows
was
conducted,
effects
on
vortical
structures
were
clarified.
Firstly,
for
apparent
features,
compared
with
diffusivity,
horn-like
has
features
smaller
scale,
weaker
swirling
strength,
shorter
evolution
cycle
lower
pressure
fluctuations.
Secondly,
dynamics
mechanism,
can
cause
additional
energy
recovery,
leads
to
higher
adverse
gradients,
so
easier
induce
shroud
backflow
near
suction
surface.
coupled
flow
field
main
flow,
namely
hub
backflow,
streamwise
periodic
oscillation
function
gradient
ω
S
·▽(▽
p/ρ
)
found,
induces
unique
vortex-street-like
distributions
deformational
vorticity
rigid
R
.
This
physical
effect
causes
mutual
competition
opposite
side.
It
originating
from
that
greatly
suppresses
development
pump.
Energy Science & Engineering,
Journal Year:
2024,
Volume and Issue:
12(7), P. 3088 - 3109
Published: June 17, 2024
Abstract
Mixed‐flow
pump
is
a
typical
using
in
low‐head
cases
of
water
lifting.
The
flow
field
pulsation
usually
an
important
issue
the
operation
mixed‐flow
pumps
and
their
pumping
statins.
Due
to
its
large
size,
it
difficult
monitor
internal
characteristics
well,
based
on
computational
fluid
dynamics,
we
use
5678
monitoring
points
which
arranged
impeller
fixed
vane
with
high
tracking
network,
pressure
signals
are
analyzed
by
fast
Fourier
transform
variable
mode
decomposition
decompose
main
frequency
intensity
signals,
then
analyze
energy
dissipation
entropy
production
rate
(EPR).
It
found
that
there
strong
low‐frequency
(0.416,
0.625,
1.67
Hz)
near
hub,
shroud
stronger
than
hub
(at
least
three
times
or
more);
stable
(25
generated
rotor–stator
interference
(RSI);
EPR
can
be
well
combined
signal.
Reasonably
allocating
material
strength
controlling
number
vanes
impellers
avoid
producing
common
multiple
caused
RSI
reduce
dissipation.
Therefore,
very
effective
improving
efficiency
this
part.
Under
low
conditions,
siphon
outflow
passage
predict
high‐frequency
(45.833
attenuation
area
through
phase
signal
signal,
has
certain
significance
for
stability
efficiency.
Physics of Fluids,
Journal Year:
2024,
Volume and Issue:
36(7)
Published: July 1, 2024
The
Bradshaw
assumption,
that
the
ratio
of
Reynolds
shear
stress
to
turbulence
kinetic
energy
(TKE)
is
a
constant
roughly
equal
0.3,
introduced
into
eddy
viscosity
and
TKE
dissipation
term
transport
model
(SST).
This
calibrated
by
zero-pressure-gradient
plate
boundary
layer
test.
not
applicable
rotating
separation
flows
in
hydraulic
machinery,
while
its
dynamic
effects
are
usually
ignored.
In
this
article,
comprehensive
evaluation
coefficient
(DBC)
SST
conducted.
First,
theoretical
analyses
existing
typical
DBCs
carried
out,
suitable
expression
form
driven
single
number
adopted
view
well-reflected
high
robustness.
According
equation
structures
SST,
three
strategies
proposed,
including
only
introducing
DBC
(SST-M1),
(SST-M2),
both
(SST-M1
+
M2).
Second,
classical
case
around
hydrofoil
employed
evaluate
application
these
strategies.
results
show
SST-M1
exhibits
severe
lift/drag
oscillations
at
large
angles
attack
accompanied
fluctuations,
indicating
poor
numerical
stability
potential
risk
strategy.
contrast,
SST-M2
M2
can
effectively
improve
deficiencies
overestimating
lift
underestimating
drag
attack,
which
attributed
promotion
earlier
larger
flow
separation.
consistency
between
two
implies
plays
key
role
enhancing
prediction
SST.
Therefore,
strategy
recommended
extend
applicability
for
machinery.
Frontiers in Physics,
Journal Year:
2024,
Volume and Issue:
12
Published: Dec. 5, 2024
The
formation
of
surface
vortices
in
axial
pump
sumps
presents
a
significant
challenge
to
performance,
primarily
due
the
risk
impeller
cavitation.
As
such,
effective
mitigation
strategies
are
imperative.
In
this
study,
strength
was
successfully
reduced
safe
operational
level
by
employing
two
distinct
types
anti-vortex
devices
(AVDs):
triangular
side
fins
type
(AVDSF)
and
ring
(AVDR).
Computational
fluid
dynamics
(CFD)
techniques
were
employed
reveal
substantial
decrease
vorticity
from
38
s
-1
absence
AVDs
approximately
8
with
either
AVDSFs
or
AVDRs,
underscoring
their
remarkable
efficacy.
Further,
helicity,
measure
vortex
twisting,
about
0.4
m
2
-2
below
0.1
introduction
ring-type
AVDs.
Detailed
analyses
velocity
streamlines
contours
elucidated
that
suppression
could
be
attributed
disruption
swirl
motion
induced
implementation
These
findings
provide
crucial
insights
into
mechanisms
underlying
suppression,
thus
paving
way
for
enhanced
performance
reliability
pump’s
suction
sump
applications.
is
expected
prevent
cavitation,
air
ingress,
vortex-induced
vibrations,
resulting
more
reliable
efficient
operation
industrial
settings.
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
