Abstract

For turbomachinery working in wet-gas conditions, liquid-phase fluid may worsen the rotordynamic characteristic of an annular seal, which induces a subsynchronous vibration problem and destabilizes the rotor-bearing system. The hole-pattern seal, demonstrated as effective to eliminate synchronous or subsynchronous vibrations for gas turbomachinery, is an ideal seal scheme to increase rotor stability and liquid tolerance capability of wet-gas turbomachinery. In this paper, the leakage and rotordynamic characteristics of a hole-pattern seal are numerically investigated under wet-gas conditions, using a three-dimensional transient CFD-based perturbation method. The accuracy and reliability of the present numerical method are demonstrated based on published experimental data. The rotordynamic force coefficients are presented and compared for the wet-gas hole-pattern seal with various inlet liquid volume fractions (LVF = 0%–20%), rotor speeds (ω = 0–20 krpm), inlet preswirl ratios (Sr = −0.2–0.5), and pressure ratios (Pr = 0.3–0.7). Numerical results show that the hole-pattern seal possesses desired tolerance capability for high inlet liquid volume fraction (LVF) of up to 20%. With inlet LVF increasing from 0 to 20%, the effective damping of the hole-pattern seal increases by about 50%, suggesting an improvement in rotor stability. The leakage flow rate of the oil-air mixture increases by 97.5%, combined with the sharply increasing oil leakage flow rate (by 636%) and decreasing air leakage flow rate (by 40%). The increasing rotor speed and inlet preswirl ratio both result in an obvious increase (by 50%) in the cross-coupled stiffness, yielding a smaller effective damping and worse rotor stability. With the increase in pressure ratio, all the rotordynamic force coefficients show a weaker frequency dependency and smaller magnitudes. The swirl velocity in the seal clearance can cause an accumulation of the liquid component in the hole cavities. With the increase of swirl velocity, more liquid component accumulates in the hole cavities, and the main accumulation position gradually moves upstream.

References

1.
Vannini
,
G.
, and
Bertoneri
,
M
, et al.,
2014
, “
Centrifugal Compressor Rotordynamics in Wet Gas Conditions
,”
43rd Turbomachinery & 30th Pump Symposia, Turbomachinery Laboratory
,
Texas A&M, University
,
Houston, TX
, Sept. 23–25, pp.
201
220
.10.21423/R1F93J
2.
San Andrés
,
L.
,
Lu
,
X.
, and
Zhu
,
J.
,
2018
, “
Leakage and Force Coefficients for Pump Annular Seals Operating With Air/Oil Mixtures: Measurements vs Predictions and Air Injection to Increase Seal Dynamic Stiffness
,”
47rd Turbomachinery &34th Pump Symposia
, Sept. 17–20, p.
175007
.https://hdl.handle.net/1969.1/175007
3.
Zhang
,
M.
,
Mclean
,
J. E.
,
Childs
,
D. W.
, et al.,
2017
, “
Experimental Study of the Static and Dynamic Characteristics of a Long Smooth Seal With Two-Phase, Mainly Air Mixtures
,”
ASME J. Eng. Gas Turbines Power
,
139
(
12
), p.
122504
.10.1115/1.4037607
4.
Brenne
,
L.
,
Gilarranz
,
J.
, and
Koch
,
J. M.
,
2005
, “
Performance Evaluation of a Centrifugal Compressor Operating Under Wet Gas Conditions
,”
34th Turbomachinery Symposia, Turbomachinery Laboratory
,
Texas A&M University
,
Houston, TX
, pp.
111
120
.10.21423/R1V35Z
5.
Bertoneri
,
M.
, and
Duni
,
S
, et al.,
2012
,. “
Measured Performance of Two-Stage Centrifugal Compressor Under Wet Gas Conditions
,”
ASME
Paper No. GT2012-69819. 10.1115/GT2012-69819
6.
Bertonneri
,
M.
,
Wilcox
,
M.
, and
Beck
,
G.
,
2014
, “
Development of Test Stand for Measuring Aerodynamic, Errosion, and Rotordynamic Performance of a Centrifugal Compressor Under Wet Gas Conditions
,”
ASME
Paper No. GT2014-25349. 10.1115/GT2014-25349
7.
Iwatsubo
,
T.
, and
Nishino
,
T.
,
1994
, “
An Experimental Study on the Static and Dynamic Characteristics of Pump Annular Seals
,” NASA, Lewis Research Center Rotordynamic Instability Problems in High-Performance Turbomachinery, Cleveland, OH, Report No. 19940029673.
8.
San Andrés
,
L.
,
Lu
,
X.
,
Lu
,
X.
, and
Liu
,
Q.
,
2016
, “
Measurements of Flow Rate and Force Coefficients in a Short-Length Annular Seal Supplied With Liquid/Gas Mixture (Stationary Journal)
,”
ASME J. Vib. Acoust.
,
59
(
4
), pp.
758
767
.10.1080/10402004.2015.1102370
9.
San Andrés
,
L.
,
2011
, “
Rotordynamic Force Coefficients of Bubbly Mixture Annular Pressure Seals
,”
ASME J. Eng. Gas Turbines Power
,
134
(
2
), p.
022503
.10.1115/1.4004130
10.
Lu
,
X.
,
2020
, “
A Nonhomogeneous Bulk Flow Model for Prediction of the Static and Dynamic Forced Performance of Two Phase Flow Annular Seals
,”
Ph.D. dissertation
,
Mechanical Engineering, Texas A&M University
,
College Station, TX
.https://hdl.handle.net/1969.1/192446
11.
Zhang
,
M.
,
2017
, “
Experiment Study of the Static and Dynamic Characteristics of a Long (L/D = 0.65) Smooth Annular Seal With Two-Phase (Liquid/Gas) Conditions
,”
Ph.D. dissertation
,
Texas a&M University
,
College Station, TX
.https://hdl.handle.net/1969.1/173126
12.
Zhang
,
M.
, and
Childs
,
D. W
, et al.,
2019
, “
A Study on the Leakage and Rotordynamic Performance of a Long Labyrinth Seal Under Mainly Air Conditions
,”
ASME J. Eng. Gas Turbines Power
,
141
(
12
), p.
121024
.10.1115/1.4045257
13.
Zhang
,
M.
, and
Childs
,
D. W.
,
2021
, “
Behaviors of a Hole-Pattern Seal With Wet-Gas
,”
ASME J. Tribol.
,
143
(
12
), p.
121807
.10.1115/1.4052254
14.
Shrestha
,
H.
, and
Childs
,
D. W
, et al.,
2019
, “
Experimental Study of the Static and Dynamic Characteristics of a Long (L/D50.75) Labyrinth Annular Seal Operating Under Two-Phase (Liquid/Gas) Conditions
,”
ASME J. Eng. Gas Turbines Power
,
141
(
12
), p.
111002
.10.1115/1.4044309
15.
Zhang
,
M.
, and
Childs
,
D. W.
,
2020
, “
A Study for Rotordynamic and Leakage Characteristics of a Long-Honeycomb Seal With Two-Phase, Mainly Air Mixtures
,”
ASME J. Eng. Gas Turbines Power
,
142
(
1
), p.
011021
.10.1115/1.4044947
16.
Zhang
,
M.
,
Childs
,
D. W.
,
Tran
,
D. L.
, and
Shresth
,
H.
,
2020
, “
Effects of Clearance on the Performance of a Labyrinth Seal Under Wet-Gas Conditions
,”
ASME J. Eng. Gas Turbines Power
,
142
(
12
), p.
111012
.10.1115/1.4048797
17.
San Andrés
,
L.
, and
Lu
,
X.
,
2018
, “
Leakage and Rotordynamic Force Coefficients of a Three-Wave (Air in Oil) Wet Annular Seal: Measurements and Predictions
,”
ASME
Paper No. 2018-75200. 10.1115/2018-75200
18.
Yang
,
J.
,
San Andrés
,
L.
, and
Lu
,
X.
,
2019
, “
Leakage and Dynamic Force Coefficients of a Pocket Damper Seal Operating Under a Wet Gas Condition: Tests Versus Predictions
,”
ASME J. Eng. Gas Turbines Power
,
141
(
11
), p.
111001
.10.1115/1.4044307
19.
San Andrés
,
L.
,
Yang
,
J.
, and
Lu
,
X.
,
2019
, “
On the Leakage, Torque, and Dynamic Force Coefficients of Air in Oil (Wet) Annular Seal: A Computational Fluid Dynamics Analysis Anchored to Test Data
,”
ASME J. Eng. Gas Turbines Power
,
141
(
2
), p.
021008
.10.1115/1.4040766
20.
Pilch
,
M.
, and
Erdman
,
C. A.
,
1987
, “
Use of Breakup Time Data and Velocity History Data to Predict the Maximum Size of Stable Fragments for Acceleration-Induced Breakup of a Liquid Drop
,”
Int. J. Multiphase Flow
,
13
(
6
), pp.
741
757
.10.1016/0301-9322(87)90063-2
21.
Li
,
Z.
,
Li
,
J.
, and
Yan
,
X.
,
2013
, “
Multiple Frequencies Elliptical Whirling Orbit Model and RANS Solutions Approach to Rotordynamic Coefficients of Annual Gas Seals Prediction
,”
ASME J. Vib. Acoust.
,
135
(
3
), p.
031005
.10.1115/1.4023143
22.
Childs
,
D. W.
,
1993
,
Turbomachinery Rotordynamic: Phenomena, Modeling and Analysis
,
Wiley
,
New York
, p.
292
.
23.
Brown
,
P. D.
, and
Childs
,
D. W.
,
2012
, “
Measurement Versus Predictions of Rotordynamic Coefficients of a Hole-Pattern Gas Seal With Negative Preswirl
,”
ASME J. Eng. Gas Turbines Power
,
134
(
12
), p.
122503
.10.1115/1.4007331
24.
Childs
,
D.
, and
Wade
,
J.
,
2004
, “
Rotordynamic-Coefficient and Leakage Characteristics for Hole-Pattern-Stator Annular Gas Seals—Measurements Versus Predictions
,”
ASME J. Tribol.
,
126
(
2
), pp.
326
333
.10.1115/1.1611502
You do not currently have access to this content.