Numerical and experimental analyses of the static and dynamic characteristics of the liquid annular seals with axially partial helical grooves were conducted to investigate the effects of the axial length gal of a helically grooved section in a seal stator. The numerical solution and experimental procedures were applied in the same manner as in previous studies on through-helically grooved seals, wherein the grooves extend across the seal length. The numerical results qualitatively agreed with the experimental results, demonstrating the validity of the numerical analysis. The leakage flow rate Q was lower in the partially helically grooved seals than that of conventional through-helically grooved seals across a small range of rotor spinning velocities. In contrast, the reduction in Q due to the pumping effect caused by the spin of the rotor diminished with the decrease in gal. For a small concentric whirling motion of the rotor, the radial dynamic reaction force Fr and magnitude of variation in the tangential dynamic reaction force Ft with the whirling angular velocity increased with the decrease in gal, and their values approached the corresponding values for the smooth-surface seal. Under the same rotor whirling velocity, the Ft for the partially helically grooved seals became lower than that for the smooth-surface seal (similar to the case for the through-helically grooved seal), although decreasing gal tended to increase Ft. These results suggest that partially helically grooved seals can improve the efficiency and stability margin of the pumps because of the reduction in leakage flow rate and suppression of the rotor forward whirling motion (with large radial and tangential dynamic reaction forces) as compared to conventional through-helically grooved seals.

References

References
1.
Kim
,
C. H.
, and
Childs
,
D. W.
,
1987
, “
Analysis for Rotordynamic Coefficients of Helically-Grooved Turbulent Annular Seals
,”
ASME J. Tribol.
,
109
(
1
), pp.
136
143
.
2.
Iwatsubo
,
T.
,
Ishimaru
,
H.
, and
Uchida
,
T.
,
1999
, “
A Study on Static and Dynamic Characteristics of Spiral-Grooved Seals
,”
JSME Trans., Ser. C
,
65
(
632
), pp.
1395
1402
.
3.
Kanki
,
H.
, and
Kawakami
,
T.
,
1988
, “
Experimental Study on the Static and Dynamic Characteristics of Screw Grooved Seals
,”
ASME J. Vib. Acoust. Stress Reliab.
,
110
(
3
), pp.
326
331
.
4.
Childs
,
D. W.
,
Nolan
,
S. A.
, and
Kilgore
,
J. J.
,
1990
, “
Test Results for Turbulent Annular Seals Using Smooth Rotors and Helically Grooved Stators
,”
ASME J. Tribol.
,
112
(
2
), pp.
254
258
.
5.
Iwatsubo
,
T.
,
Sheng
,
B. C.
, and
Ono
,
M.
,
1990
, “
Experiment of Static and Dynamic Characteristics of Spiral Grooved Seals
,”
Rotor Dynamic Instability Problems in High-Performance Turbomachinery, National Aeronautics and Space Administration, Washington, DC
, pp.
223
233
.
6.
Nagai
,
K.
,
Kaneko
,
S.
,
Taura
,
H.
, and
Watanabe
,
Y.
,
2018
, “
Numerical and Experimental Analyses of Static Characteristics for Liquid Annular Seals With Helical Grooves in Seal Stator
,”
ASME J. Tribol.
,
140
(
3
), p.
032201
.
7.
Nagai
,
K.
,
Kaneko
,
S.
,
Taura
,
H.
, and
Watanabe
,
Y.
,
2018
, “
Numerical and Experimental Analyses of Dynamic Characteristics for Liquid Annular Seals With Helical Grooves in Seal Stator
,”
ASME J. Tribol.
,
140
(
5
), p.
052201
.
8.
Ishimaru
,
H.
, and
Iwatsubo
,
T.
,
2001
, “
Improvement of the Stability and Reduction of the Leakage of Grooved Seals—1st Report, Installation of Swirl Breakers to All Circumferential Grooves
,”
JSME Trans., Ser. C
,
67
(
661
), pp.
2821
2828
.
9.
Ishimaru
,
H.
, and
Iwatsubo
,
T.
,
2001
, “
Improvement of the Stability and Reduction of the Leakage of Grooved Seals—2nd Report, Installation of Swirl Breakers in Circumferential and Helical Grooves Just Behind of the Entrance of Seals
,”
JSME Trans., Ser. C
,
67
(
661
), pp.
2829
2836
.
10.
Kaneko
,
S.
,
Hori
,
Y.
, and
Tanaka
,
M.
,
1984
, “
Static and Dynamic Characteristics of Annular Plain Seals
,”
Proc. Inst. Mech. Eng., Part C
,
84
, pp.
205
214
.
11.
Hori
,
Y.
,
2006
,
Hydrodynamic Lubrication
,
Springer-Verlag
,
Tokyo, Japan
, pp.
204
210
.
12.
Patankar
,
S. V.
,
1980
,
Numerical Heat Transfer and Fluid Flow
,
McGraw-Hill
,
New York
, pp. 52–54.
13.
Childs
,
D. W.
,
1993
,
Turbomachinery Rotordynamics, Phenomena, Modeling, and Analysis
,
Wiley
,
New York
, pp.
250
251
.
14.
ANSI/ASME
,
1986
, “
Measurement Uncertainty—Part 1
,” American Society of Mechanical Engineers, New York, Standard No. PTC 19.1-1985.
15.
Childs
,
D. W.
, 1993,
Turbomachinery Rotordynamics, Phenomena, Modeling, and Analysis
, Wiley, New York, pp. 240–241.
16.
Childs
,
D. W.
,
Nolan
,
S. A.
, and
Kilgore
,
J. J.
,
1990
, “
Additional Test Results for Round-Hole Pattern Damper Seals: Leakage, Friction Factors, and Rotordynamic Force Coefficients
,”
ASME J. Tribol.
,
112
(
2
), pp.
365
371
.
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