IOP Conference Series Earth and Environmental Science,
Год журнала:
2024,
Номер
1411(1), С. 012005 - 012005
Опубликована: Ноя. 1, 2024
Abstract
Francis
turbines
have
a
leakage
loss
from
the
corresponding
labyrinth
seals
i.e.,
crown
side
and
skirt
clearance.
Therefore,
clearance
between
runner
turbine
cover
plays
an
important
role
in
hydrodynamic
characteristics
of
hydro
turbine.
Generally,
geometrical
details
are
not
considered
numerical
model
due
to
complexity
involved
modelling
requirement
high
computational
power
that
may
lead
inaccurate
prediction
performance
In
present
investigation,
steady-state
simulations
been
performed
on
head
turbine,
under
different
operating
conditions,
ranging
part
load
overload
condition,
assess
influence
FVM
method
(as
discretization
method)
along
with
SST
k-omega
turbulence
has
adopted
for
modelling.
The
simulation
results
such
as
hydraulic
efficiency
output
validated
test
which
was
done
per
IEC
60193
standard
found
satisfactory
agreement.
Further,
axial
thrust
force
is
also
computed
conditions
compared
results.
Based
results,
it
0.4%
-
1.1%
lower
than
without
higher
at
part-load
condition
other
conditions.
It
observed
almost
same
all
loading
particular
fall
range
0.61%
0.81%.
value
increases
discharge
maximum
203
kN
condition.
Physics of Fluids,
Год журнала:
2024,
Номер
36(10)
Опубликована: Окт. 1, 2024
To
stabilize
the
operation
of
pumped
storage
power
station,
an
orthogonal
experimental
design
was
proposed
to
optimize
return
channel
with
splitter
blades
pump
turbine.
The
calculation
results
various
models
under
multiple
operating
conditions
indicated
that
inlet
distance
a1
and
blade
number
z
considerably
affect
efficiency
flow
pattern
in
passage.
optimal
scheme
improved
by
nearly
3%
at
0.6Qd.
Savitzky–Golay
filtering
method
Fast
Fourier
Transform
were
used
analyze
unsteady
characteristics
turbine
model.
amplitude
pressure
pulsations
passing
frequency
vaneless
space
interference
zone
between
guide
vane
reduced
considerably,
pulsation
decreased
50%,
48%,
20%
for
0.6Qd,
1.0Qd,
1.1Qd
conditions.
A
Continuous
Wavelet
signals
during
shutdown
transition
process.
optimization
their
corresponding
passages
suppressed
high-amplitude
unit
stable
station.
The
pumped
storage
hydropower
(PSHP)
has
large
head
variations
during
its
cyclic
operation,
and
using
variable
speed
units
of
reversible
pump
turbines
(RPT)
can
extend
operating
range
grid
stability.
In
minimum
conditions,
the
performance
RPT
in
turbine
mode
is
more
important
because
it
may
experience
fatigue
vibrations
due
to
hydraulic
instabilities
caused
by
rotor-stator
interaction
(RSI)
vaneless
space
vortex
rope
draft
tube.
Therefore,
investigate
these
phenomena
RPTs
at
head.
At
flow
rate,
controller
adjusts
rotational
value
that
yields
highest
efficiency,
becomes
“fixed”
condition.
present
work
investigates
RSI
associated
pressure
fluctuations
(PFs)
available
conditions.
analysis
was
performed
best
efficiency
point
(BEP)
with
three
rates
having
fixed
(corresponding
efficiency).
It
observed
fluctuates
as
a
result
presence
low-pressure
stagnation
region
inlet
side
runner
blade.
developed
tube
center
high-velocity
gradient.
be
concluded
main
source
PF
condition
RSI.
When
reversible
pump
turbines
go
through
the
S-shape
region,
there
is
some
significant
backflow
regions
in
vaneless
space,
accompanied
by
severe
pressure
fluctuation.
However,
internal
correlation
and
mutual
influence
mechanism
among
fluctuation,
turbulent
vortex
structure,
are
still
unclear
enough
current
research.
In
this
work,
characteristics
formation
of
turbine
region
figured
out
using
computational
fluid
dynamics
methods.
The
results
indicate
that
Leading-Edge-Passage-Vortex
caused
adverse
gradient
dominant
initial
stage
backflow.
stage,
interaction
between
inflow
main
reason
causing
high
amplitude
wideband
fluctuation
components
space.
development,
centrifugal
force
play
roles
different
regions,
respectively.
rotating
stall
phenomenon
appears
runner
a
low-frequency
component
0.6fn
0.3fn∼0.45fn
appeared,
respectively,
space
runner.
fully
developed
dominated
concentrated
flow
area
inlet,
while
pushed
to
upper
crown
lower
ring.
These
findings
can
provide
theoretical
supports
for
improving
stability
operating
off-design
condition.
Surge
chambers
play
a
critical
role
in
moderating
oscillations
pumped
storage
power
stations
after
load
disturbances.
Owing
to
the
high
costs,
increased
risks,
and
extended
construction
times
associated
with
conventional
surge
(CSCs),
we
proposed
shaft
coaxial
chamber
(SCSC)
as
an
alternative,
which
was
otherwise
compact,
economical,
construction-friendly
structural
configuration.
The
present
study
aimed
investigate
hydraulic
oscillations,
stability,
flow
characteristics
of
SCSC
compared
CSC
under
disturbance
conditions.
Physical
models
both
types
were
developed
validated.
results
indicated
that
novel
system
could
maintain
stability
before
disturbances;
its
fluctuations
slightly
higher
than
those
CSC,
particularly
pumping
During
disturbance,
water
level
fluctuation
amplitudes
at
least
1.43
2.24
different
working
conditions
10%
disturbance.
As
frequency
increased,
approached
CSC.
Moreover,
new
discharge
coefficient
range
0.9–1.2
for
proposed,
increasing
standard
values
by
1.5
times.
In
conclusion,
unstable
patterns
connecting
pipe
are
mechanisms
influence
SCSC.
These
findings
provide
valuable
theoretical
guidance
practical
applications.
Journal of Marine Science and Engineering,
Год журнала:
2024,
Номер
12(12), С. 2243 - 2243
Опубликована: Дек. 6, 2024
Pumped
storage
units
often
deviate
from
the
optimal
operating
conditions
in
process
of
regulating
new
energy
fluctuations.
To
effectively
improve
performance
units,
variable
speed
is
one
more
feasible
means
at
present.
This
paper
focuses
on
part-load
condition
turbine
operation,
with
an
emphasis
internal
flow
characteristics
and
pressure
pulsation
pump
during
linear
reduction
rated
speed.
It
found
that
streamlines
runner
become
turbulent
reduction,
forming
a
vortex
inlet
runner,
scale
gradually
increases
reduction.
The
rope
draft
tube
undergoes
three
types
changes
reduction:
helical
eccentric
rope,
vanishing
columnar
rope.
Before
change,
low-frequency
components
high
amplitude
exist
each
flow-passing
part,
but
disappear
Except
for
frequency
affected
by
rotor–stator
interference
part
decrease
speed,
growth
most
obvious
vaneless
region.
findings
this
research
can
serve
as
valuable
reference
operation
pumped
units.
IOP Conference Series Earth and Environmental Science,
Год журнала:
2024,
Номер
1411(1), С. 012028 - 012028
Опубликована: Ноя. 1, 2024
Abstract
Efficiency
and
grid
stability
of
pumped
storage
plants
with
significant
head
variations
can
be
enhanced
by
the
implementation
variable
speed
operation.
The
reversible
pump-turbine
(RPT)
operating
in
turbine
mode
is
particularly
prone
to
fatigue
vibrations
when
at
maximum
conditions,
primarily
due
hydraulic
instabilities
caused
pressure
fluctuations
vaneless
space
thus,
performance
RPT
becomes
increasingly
critical
under
such
conditions.
It
is,
therefore,
important
examine
RPTs
higher
heads.
findings
indicate
that
main
source
across
all
conditions
rotor-stator
interaction
(RSI),
where
dominant
frequency
blade
passing
(9
f
n
)
its
harmonics.
