M ar.
2011
T ransactions of N anjing U niversity of Aeronautics & Astronautics
V
o\.
28
N
o.
1
VIBRATION NUMERICAL ANALYSIS OF
COUNTER
-J之
OTATING
TURBINE
矶
TITH
引
TAKE
-F
LO
辆
T
USING
FLUID-STRUCTURE INTERACTION METHOD
Zh
αo
Zhenhu
α
Lu
Wenliang
2
, Chen Wei
1
,
Wu
Tieying
1
(1. College of Energy and Power Engineering,
NU
AA
,
29
Yudao Street, Nanjing, 210016, P.
R.
China;
2.
The
Third Academy , China Aerospace Science and Technology Corporation, Beijing, 100074, P.
R.
China)
Abstract: T he design of counter
-r
otating turbine
is
one of
new
techniques to
im
prove the
thrust
吓
veight
ratio of jet
propulsion engines. N umerical analysis of a
low
pressure (LP) counter
....
rotating turbine rotor blade
is
presented
by
using ANSYS/CFX software. Interaction of aerodynamics and solid mechanics coupling
in
the computation
is
applied. In some rating of turbine, stress distribution and vibration characteristics of
low
pressure turbine( LPT)
blade are
com
puted. T he wake aerodynamic forces and LPT blade vibration are transformed
in
frequency domain
using fast Fourier transform
(FFT)
method. T
he
results show that under wake aerodynamic force excitation, the
first order modal vibration
is
more easily aroused and the higher order response cannot be ignored. M oreover,
w ith different temperature fields , the vibration responses of blade are also different.
Key words: counter
-r
otating turbine; fluid and structure coupling; vibration responses; numerical analysis
CLC number: V
231
. 92; V 232. 4 Document code: A Arti
cI
e ID: 1 005-1120(
201
1)
01
-D
066
-D
7
INTRODUCTION
The
counter
""1"
otating
turbine
is
that
,
in
a
twin
spool
turbo
--e
ngine
,
two
rotors
rotate
in
the
opposite
directions
,
and
there
may
be
no
nozzle
guide
vane
(NGV)
between
the
two
rotors
in
or-
der
to
save
weight
,
to
increase
thrust
咐
eight
ra-
tio
and
probably
to
improve
engine
performance.
In
recent
years
,
great
progresses
have
been
made
in
technology
of
the
counter
""1"
otating
turbine.
Studies
show
that
the
use
of
counter
""1"
otating
tur-
bine
structure
can
reduce
the
number
of
compo-
nents
,
lighten
the
structural
quality
,
improve
aerodynamic
performance
,
reduce
gyroscopic
mo-
ment
and
so
on.
Counter
""1"
otating
turbines
have
great
many
advantages
over
conventional
tur-
bines[
1-3] •
the
blades.
In
the
other
hand
,
low
pressure
(LP)
blades
of
the
turbine
are
relatively
thin.
A t
the
high
tem
peratur
飞
blade
stiffness
decreases
and
blade
displacement
may
be
significant
enough
to
influence
flow
field.
In
this
case
,
the
research
based
on
fluid
and
structure
coupling
is
neces-
sary.
The
analysis
in
this
paper
,
based
on
AN-
SYSI
CFX
software
, is
in
3-D,
unsteady
and
flu-
id
-s
olid
coupling
numerical
computation
to
ana-
lyze
vibration
response
and
stress
field
of
low
pressure
t
旧
bine
(LPT)
blades
as
well
as
impact
of
temperature
on
the
calculation
results.
1
MEmOD
FOR
FLUID-STRUC-
TURE COUPLING CACULA-
TION
How
ever
,
upstream
blades
generate
wake-
Fluid
-s
olid
coupling
mechanics
is a
branch
of
flows
that
become
periodical
disturbance
for
the
fluid
and
solid
mechanics
interaction
,
and
downstream
blades.
When
frequency
matches
many
researchers
have
made
great
contributions
natural
frequency
of
blades
,
such
pulses
may
ex-
in
this
area.
A K Slone[5]
solved
the
problem
in
cite
vibration
and
causes
high
cycle
fatigue[
4]
of
the
fluid
-s
olid
coupling
of
transient
dynamics
w
ith
Received date: 2010-10-18; revision received date:
20
11
-D
1
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6
E-mail: zhaozh27@yahoo.com.cn