Machines,
Journal Year:
2024,
Volume and Issue:
12(10), P. 687 - 687
Published: Sept. 30, 2024
Due
to
the
effects
of
swing
motion,
performances
and
internal
flow
characteristics
marine
centrifugal
pump
undergo
some
unsteady
variations
in
environment.
The
hydraulic
test
system
with
six
degree
freedom
parallel
motion
platform
is
established
study
performance
at
different
heel
angles
steady
roll
position
pitch
position.
head
gradually
decreases
as
angle
increases.
has
decreased
by
7%
reach
minimum
15°
At
same
angle,
lower
than
that
under
rated
condition.
fluid
impeller
passage
subjected
additional
inertial
force
or
inducing
bias
phenomena
velocity
field.
development
induces
intense
vortex
shedding
dissipation
interblade
vortices
are
affected.
periodic
flow-induced
pulsation
obviously
appear
passage.
periodicity
pressure
amplitude
influenced
due
motion.
greater
excitation
fluid-induced
vibration
amplitude.
In
addition
low
frequencies,
20
times
shaft
frequency
evident
Water,
Journal Year:
2023,
Volume and Issue:
15(20), P. 3706 - 3706
Published: Oct. 23, 2023
Pitch
motion
is
the
key
factor
affecting
performance
characteristics
of
centrifugal
pumps
on
board
ships
and
exacerbates
hydraulic
excitation
to
induce
unsteady
vibration
pump
units.
A
test
platform
with
swing
established
explore
effects
pitch
a
pump’s
characteristics.
An
obvious
hump
zone
exists
in
head
characteristic
curve
low-flow-rate
condition
due
motion.
The
shut-off
has
significant
decrease
motion,
compared
static
state.
gradually
increases
as
maximum
angle
or
period
shortens.
Specifically,
rated
flow
decreases
by
6.3
%
reach
minimum
at
20
degrees
5
s.
Based
multiple-reference
coordinate
system,
large
eddy
simulation
shear-modified
viscosity
model
employed
simulate
inner
under
influence
distinct
vortex
appears
near
blade
suction
surface
becomes
increasingly
turbulent
intensifies
stretching
deformation
vortices.
periodic
variations
fluid-induced
pressure
over
time
present
parabolic
features,
amplitude
frequency
domain
reaches
its
value
within
Physics of Fluids,
Journal Year:
2024,
Volume and Issue:
36(7)
Published: July 1, 2024
Energy
performance
is
a
crucial
parameter
for
evaluating
two-way
pumping
station.
However,
the
sharp
decrease
in
efficiency
within
overload
flow
rates
presents
challenge.
To
address
this
issue,
controllable
diffusion
technology
(CDT)
developed
based
on
asymmetric
inflow
theory.
Transient
numerical
simulation
carried
out
under
five
different
distortion
angles.
The
energy
and
entropy
production
dissipation
before
after
application
of
CDT
are
comprehensively
studied.
(a)
First,
successfully
improves
operation
rate
range.
reverse
has
better
improvement
effect
than
syntropic
distortion.
(b)
Second,
conditions,
reduction
axial
velocity
causes
best-efficiency
point
to
deviate
toward
rate.
This
leads
an
increase
total
(TEP)
0.7Qdes–0.95Qdes,
followed
by
1.05Qdes–1.3Qdes.
(c)
Third,
CDT-induced
horizontal
mismatch
between
impeller
angle
blade
placement
angle,
which
uneven
spatial
distribution
inside
Machines,
Journal Year:
2024,
Volume and Issue:
12(10), P. 687 - 687
Published: Sept. 30, 2024
Due
to
the
effects
of
swing
motion,
performances
and
internal
flow
characteristics
marine
centrifugal
pump
undergo
some
unsteady
variations
in
environment.
The
hydraulic
test
system
with
six
degree
freedom
parallel
motion
platform
is
established
study
performance
at
different
heel
angles
steady
roll
position
pitch
position.
head
gradually
decreases
as
angle
increases.
has
decreased
by
7%
reach
minimum
15°
At
same
angle,
lower
than
that
under
rated
condition.
fluid
impeller
passage
subjected
additional
inertial
force
or
inducing
bias
phenomena
velocity
field.
development
induces
intense
vortex
shedding
dissipation
interblade
vortices
are
affected.
periodic
flow-induced
pulsation
obviously
appear
passage.
periodicity
pressure
amplitude
influenced
due
motion.
greater
excitation
fluid-induced
vibration
amplitude.
In
addition
low
frequencies,
20
times
shaft
frequency
evident
