The correct computation of steam subcooling, subsequent formation of nuclei and finally droplet growth is the basic prerequisite for a quantitative assessment of the wetness losses incurred in steam turbines due to thermal and inertial relaxation. The same basically applies for the prediction of droplet deposition and the resulting threat of erosion. Despite the fact that there are many computational fluid dynamics (CFD)-packages that can deal with real-gas effects in steam flows, the accurate and reliable prediction of subcooling, condensation, and wet steam flow in steam turbines using CFD is still a demanding task. One reason for this is the lack of validation data for turbines that can be used to assess the physical models applied. Experimental data from nozzle and cascade tests can be found in the open literature; however, these measurement results are only partly useful for validation purposes for a number of reasons. With regard to steam turbine test data, there are some publications, yet always without any information about the turbine stage geometries. This publication is part of a two-part paper; whereas Part I focuses on the numerical validation of wet steam models by means of condensing nozzle and cascade flows, the focus in this part lies on the comparison of CFD results of the turbine flow to experimental data at various load conditions. In order to assess the validity and reliability of the experimental data, the method of measurement is presented in detail and discussed. The comparison of experimental and numerical results is used for a discussion about the challenges in both modeling and measuring steam turbine flows, presenting the current experience and knowledge at Institute of Thermal Turbomachinery and Machinery Laboratory (ITSM).

References

References
1.
Grübel
,
M.
,
Starzmann
,
J.
,
Schatz
,
M.
,
Eberle
,
T.
,
Vogt
,
D.
, and
Sieverding
,
F.
, “
Two-Phase Flow Modeling and Measurements in Low-Pressure Turbines—Part I: Numerical Validation of Wet Steam Models and Turbine Modeling
,”
ASME J. Gas Turbine Power
137
(
4
), p.
042602
.10.1115/1.4028468
2.
Guha
,
A.
, and
Young
,
J.
,
1994
, “
The Effect of Flow Unsteadiness on the Homogeneous Nucleation of Water Droplets in Steam Turbines
,”
Philos. Trans. R. Soc. London A
,
349
(
1691
), pp.
445
472
.10.1098/rsta.1994.0141
3.
Walters
,
P. T.
,
1985
, “
Wetness and Efficiency Measurements in L.P. Turbines With an Optical Probe as an Aid to Improving Performance
,”
ASME J. Eng. Gas Turbines Power
,
109
(
1
), pp.
85
91
.10.1115/1.3240010
4.
Walters
,
P. T.
, and
Skingley
,
P. C.
,
1979
, “
An Optical Instrument for Measuring the Wetness Fraction and Droplet Size of Wet Steam Flows in LP Turbines
,”
Proc. Inst. Mech. Eng., Part C
,
141
(
79
), pp.
337
348
.
5.
Petr
,
V.
, and
Kolovratnik
,
M.
,
2003
, “
Diagnostics of Wet Steam in LP Steam Turbines
,”
5th European Conference on Turbomachinery, Fluid Dynamics and Thermodynamics
,
Prague
, Czech Republic, Mar. 17–22, pp.
687
689
.
6.
Wróblewski
,
W.
,
Dykas
,
S.
,
Gardzilewicz
,
A.
, and
Kolovratnik
,
M.
,
2009
, “
Numerical and Experimental Investigations of Steam Condensation in LP Part of a Large Power Turbine
,”
ASME. J. Fluids Eng.
,
131
(
4
), p.
041301
.10.1115/1.3089544
7.
Cai
,
X.
,
Ning
,
T.
,
Niu
,
F.
,
Wu
,
G.
, and
Song
,
Y.
,
2009
, “
An Investigation of Wet Steam Flow in a 300 MW Direct Air-Cooling Steam Turbine. Part 1: Measurement Principles, Probe, and Wetness
,”
Proc. Inst. Mech. Eng., Part A
,
223
(
5
), pp.
625
634
.10.1243/09576509JPE690
8.
Chandler
,
K.
,
White
,
A. J.
, and
Young
,
J. B.
,
2012
, “
Comparison of Unsteady Non-Equilibrium Wet-Steam Calculations With Model Turbine Data
,”
Baumann Centenary Wet Steam Conference
,
Cambridge, UK
, Sept. 10–11, Paper No. BCC-2012-10.
9.
Schatz
,
M.
, and
Casey
,
M. V.
,
2006
, “
Design and Testing of a New Miniature Combined Optical/Pneumatic Wedge Probe for the Measurement of Steam Wetness
,”
AIP Conf. Proc.
,
914
(
1
), pp.
464
479
.10.1063/1.2747469
10.
Schatz
,
M.
, and
Eberle
,
T.
,
2014
, “
Experimental Study of Steam Wetness in a Model Steam Turbine Rig: Presentation of Results and Comparison With Computational Fluid Dynamics Data
,”
Proc. Inst. Mech. Eng., Part A
,
228
(
2
), pp.
129
142
.10.1177/0957650913512313
11.
Eberle
,
T.
,
Schatz
,
M.
,
Starzmann
,
J.
,
Grübel
,
M.
, and
Casey
,
M. V.
,
2014
, “
Experimental Study of the Effects of Temperature Variation on Droplet Size and Wetness Fraction in a Low Pressure Model Steam Turbine
,”
Proc. Inst. Mech. Eng., Part A
,
228
(
1
), pp.
97
106
.10.1177/0957650913508119
12.
VDI-Gesellschaft
,
1999
,
VDI 2043: Measurement of Steam Wetness Fraction
,
VDI-Handbuch Energietechnik
,
Düsseldorf, Germany
.
13.
Kleitz
,
A.
, and
Dorey
,
J. M.
,
2004
, “
Instrumentation for Wet Steam
,”
Proc. Inst. Mech. Eng., Part C
,
218
(
8
), pp.
811
842
.10.1243/0954406041474192
14.
Segelstein
,
D. J.
,
1981
, “
The Complex Refractive Index of Water
,” M.S. thesis, University of Missouri, Kansas City, MO.
15.
Bohren
,
C. F.
, and
Huffman
,
D. R.
,
1998
,
Absorption and Scattering of Light by Small Particles
,
Wiley
,
New York
.
16.
Wriedt
,
T.
,
1998
, “
A Review of Elastic Light Scattering Theories
,”
Part. Part. Syst. Charact.
,
15
(
2
), pp.
67
74
.10.1002/(SICI)1521-4117(199804)15:2<67::AID-PPSC67>3.0.CO;2-F
17.
Barber
,
P. W.
, and
Hill
,
S. C.
,
1990
,
Light Scattering by Particles
,
World Scientific
,
Singapore
.
18.
Jones
,
A.
,
1999
, “
Light Scattering for Particle Characterization
,”
Prog. Energy Combust. Sci.
,
25
(
1
), pp.
1
53
.10.1016/S0360-1285(98)00017-3
19.
Schatz
,
M.
,
2012
, “
Determination of the Composition of the Two-Phase-Flow in Low-Pressure Steam Turbines Based on the Light Extinction Method
,” Doctoral thesis, University of Stuttgart, Stuttgart, Germany.
20.
Ramachandran
,
G.
, and
Leith
,
D.
,
1992
, “
Extraction of Aerosol-Size Distributions From Multispectral Light Extinction Data
,”
Aerosol. Sci. Technol.
,
17
(
4
), pp.
303
325
.10.1080/02786829208959578
21.
Twomey
,
S
.,
1963
, “
On the Numerical Solution of Fredholm Integral Equations of the First Kind by the Inversion of the Linear System Produced by Quadrature
,”
J. Assoc. Comput. Mach.
,
10
(
1
), pp.
97
101
.10.1145/321150.321157
22.
Lawson
,
C. L.
, and
Hanson
,
R. J.
,
1995
,
Solving Least Squares Problems
,
SIAM, Philadelphia
,
PA
.
23.
Sigg
,
R.
,
Heinz
,
C.
,
Casey
,
M. V.
, and
Sürken
,
N.
,
2009
, “
Numerical and Experimental Investigation of a Low-Pressure Steam Turbine During Windage
,”
Proc. Inst. Mech. Eng., Part A
,
223
(
6
), pp.
697
708
.10.1243/09576509JPE826
24.
Heinz
,
C.
,
Schatz
,
M.
,
Casey
,
M. V.
, and
Stüer
,
H.
,
2010
, “
Experimental and Analytical Investigations of a Low Pressure Model Steam Turbine During Forced Response Excitation
,”
ASME
Paper No. GT2010-22146.10.1115/GT2010-22146
25.
Starzmann
,
J.
,
Casey
,
M. V.
, and
Sieverding
,
F.
,
2010
, “
Non-Equilibrium Condensation Effects on the Flow Field and the Performance of a Low Pressure Steam Turbine
,”
ASME
Paper No. GT2010-22467.10.1115/GT2010-22467
26.
Starzmann
,
J.
,
Schatz
,
M.
,
Casey
,
M. V.
,
Mayer
,
J. F.
, and
Sieverding
,
F.
,
2011
, “
Modelling and Validation of Wet Steam Flow in a Low Pressure Steam Turbine
,”
ASME
Paper No. GT2011-45672.10.1115/GT2011-45672
27.
Guha
,
A.
,
1998
, “
A Unified Theory for the Interpretation of Total Pressure and Temperature in Two-Phase Flows at Subsonic and Supersonic Speeds
,”
Philos. Trans. R. Soc.
, A,
454
(
470
), pp.
671
695
.10.1098/rspa.1998.0180
28.
Bakhtar
,
F.
, and
Heaton
,
A. V.
,
2005
, “
Effects Of wake Chopping on Droplet Sizes in Steam Turbines
,”
Proc. Inst. Mech. Eng., Part C
,
219
(
12
), pp.
1357
1367
.10.1243/095440605X69291
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