The characteristics of pressure fluctuations in a prototype reversible pump turbine (RPT) is investigated within a wide range of load conditions with a focus on the low-load condition (e.g., 25% of rated power) with the aid of pressure signals obtained at several typical recording points (i.e., spiral casing, vaneless space, draft tube cone, and draft tube elbow). Our findings reveal that at the low-load condition, the pressure fluctuation is quite significant (e.g., above 12% in terms of nondimensional values), especially in the vaneless space and spiral casing with the dominant frequency being the blade passing frequency. Furthermore, based on the characteristics of pressure fluctuation, the investigated load range is divided into three zones. For zone I (with low load), the amplitude of pressure fluctuation is highest and the dominant mechanism is the rotor–stator interaction in the vaneless space with the blade passing frequency. For zone II (with medium load), the amplitude of pressure fluctuation is less prominent (below 5%) and the dominant mechanism is the low-frequency fluctuations induced by the swirling vortex rope. For zone III (with high load), the amplitude of pressure fluctuation is quite limited (less than 3%) and the dominant mechanism is still the rotor–stator interaction but with the dominant frequency being the harmonics of blade passing frequency. Detailed examples for all three zones are given and discussed with quantitative descriptions of propagation mechanism of fluctuation.

Reference

Reference
1.
Zhang
,
Y.
,
Tang
,
N.
,
Niu
,
Y.
, and
Du
,
X.
,
2016
, “
Wind Energy Rejection in China: Current Status, Reasons and Perspectives
,”
Renewable Sustainable Energy Rev.
,
66
, pp.
322
344
.
2.
Zhang
,
Y.
,
Zhang
,
Y.
, and
Wu
,
Y.
,
2017
, “
A Review of Rotating Stall in Reversible Pump Turbine
,”
Proc. Inst. Mech. Eng., Part C
(accepted).
3.
Hasmatuchi
,
V.
,
Farhat
,
M.
,
Roth
,
S.
,
Botero
,
F.
, and
Avellan
,
F.
,
2011
, “
Experimental Evidence of Rotating Stall in a Pump-Turbine at Off-Design Conditions in Generating Mode
,”
ASME J. Fluids Eng.
,
133
(
5
), p.
051104
.
4.
Widmer
,
C.
,
Staubli
,
T.
, and
Ledergerber
,
N.
,
2011
, “
Unstable Characteristics and Rotating Stall in Turbine Brake Operation of Pump-Turbines
,”
ASME J. Fluids Eng.
,
133
(
4
), p.
041101
.
5.
Cavazzini
,
G.
,
Alberto
,
C.
,
Giorgio
,
P.
, and
Guido
,
A.
,
2016
, “
Analysis of the Unstable Behavior of a Pump-Turbine in Turbine Mode: Fluid-Dynamical and Spectral Characterization of the S-Shape Characteristic
,”
ASME J. Fluids Eng.
,
138
(
2
), p.
021105
.
6.
Botero
,
F.
,
Hasmatuchi
,
V.
,
Roth
,
S.
, and
Farhat
,
M.
,
2014
, “
Non-Intrusive Detection of Rotating Stall in Pump-Turbines
,”
Mech. Syst. Signal Process.
,
48
(
1–2
), p.
162
.
7.
Olimstad
,
G.
,
Nielsen
,
T.
, and
Børresen
,
B.
,
2012
, “
Dependency on Runner Geometry for Reversible-Pump Turbine Characteristic in Turbine Mode of Operation
,”
ASME J. Fluids Eng.
,
134
(
12
), p.
121102
.
8.
Olimstad
,
G.
,
Nielsen
,
T.
, and
Børresen
,
B.
,
2012
, “
Stability Limits of Reversible Pump Turbines in Turbine Mode of Operation and Measurements of Unstable Characteristic
,”
ASME J. Fluids Eng.
,
134
(
11
), p.
111202
.
9.
Li
,
Z.
,
Wang
,
Z.
,
Wei
,
X.
, and
Qin
,
D.
,
2016
, “
Flow Similarity in the Rotor–Stator Interaction Affected Region in Prototype and Model Francis Pump-Turbines in Generating Mode
,”
ASME J. Fluids Eng.
,
138
(
6
), p.
061201
.
10.
Xia
,
L.
,
Cheng
,
Y.
,
You
,
J.
,
Zhang
,
X.
,
Yang
,
J.
, and
Qian
,
Z.
,
2017
, “
Mechanism of the S-Shaped Characteristics and the Runaway Instability of Pump-Turbines
,”
ASME J. Fluids Eng.
,
139
(
3
), p.
031101
.
11.
Zeng
,
W.
,
Yang
,
J.
,
Hu
,
J.
, and
Yang
,
J.
,
2016
, “
Guide-Vane Closing Schemes for Pump-Turbines Based on Transient Characteristics in S-Shaped Region
,”
ASME J. Fluids Eng.
,
138
(
5
), p.
051302
.
12.
Yang
,
J.
,
Pavesi
,
G.
,
Yuan
,
S.
,
Cavazzini
,
G.
, and
Ardizzon
,
G.
,
2015
, “
Experimental Characterization of a Pump–Turbine in Pump Mode at Hump Instability Region
,”
ASME J. Fluids Eng.
,
137
(
5
), p.
051109
.
13.
Pacot
,
O.
,
Chisachi
,
K.
,
Yang
,
G.
,
Yoshinobu
,
Y.
, and
François
,
A.
,
2016
, “
Large Eddy Simulation of the Rotating Stall in a Pump-Turbine Operated in Pumping Mode at a Part-Load Condition
,”
ASME J. Fluids Eng.
,
138
(
11
), p.
111102
.
14.
Egusquiza
,
E.
,
Valero
,
C.
,
Valentin
,
D.
,
Presas
,
A.
, and
Rodriguez
,
C. G.
,
2015
, “
Condition Monitoring of Pump-Turbines. New Challenges
,”
Measurement
,
67
, p.
151
.
15.
Egusquiza
,
E.
,
Valero
,
C.
,
Huang
,
X.
,
Jou
,
E.
,
Guardo
,
A.
, and
Rodriguez
,
C.
,
2012
, “
Failure Investigation of a Large Pump-Turbine Runner
,”
Eng. Failure Anal.
,
23
, p.
27
.
16.
Martin
,
C. S.
,
1986
, “
Stability of Pump-Turbines During Transient Operation
,”
5th International Conference on Pressure Surges BHRA
, Hannover, Germany, Sept. 22–24, pp. 61–71.
17.
Gentner
,
C.
,
Sallaberger
,
M.
,
Widmer
,
C.
,
Bobach
,
B.-J.
,
Jaberg
,
H.
,
Schiffer
,
J.
,
Senn
,
F.
, and
Guggenberger
,
M.
,
2014
, “
Comprehensive Experimental and Numerical Analysis of Instability Phenomena in Pump Turbines
,”
IOP Conf. Ser.: Earth Environ. Sci.
,
22
(
3
), p.
032046
.
18.
Zhang
,
X.
,
Cheng
,
Y.
,
Xia
,
L.
,
Yang
,
J.
, and
Qian
,
Z.
,
2016
, “
Looping Dynamic Characteristics of a Pump-Turbine in the S-Shaped Region During Runaway
,”
ASME J. Fluids Eng.
,
138
(
9
), p.
091102
.
19.
Dörfler
,
P.
,
Sick
,
M.
, and
Coutu
,
A.
,
2013
,
Flow-Induced Pulsation and Vibration in Hydroelectric Machinery
(Engineer's Guidebook for Planning, Design and Troubleshooting),
Springer Science & Business Media
, Berlin.
20.
Cencîc
,
T.
,
Hoĉevar
,
M.
, and
Ŝirok
,
B.
,
2014
, “
Study of Erosive Cavitation Detection in Pump Mode of Pump–Storage Hydropower Plant Prototype
,”
ASME J. Fluids Eng.
,
136
(
5
), p.
051301
.
You do not currently have access to this content.