Abstract

The isentropic exponent is one of the most important properties affecting gas dynamics. Nonetheless, its effect on turbine performance is not well known. This paper discusses a series of experimental and computational studies to determine the effect of isentropic exponent on the flow field within a turbine vane. Experiments are performed using a newly modified transient wind tunnel that enables annular cascade testing with a wide range of working fluids and operating conditions. For the present study, tests are undertaken using air, CO2, R134a, and argon, giving a range of isentropic exponent from 1.08 to 1.67. Measurements include detailed wall static pressures that are compared with computational simulations. Our results show that over the range of isentropic exponents tested here, the loss can vary between 20% and 35%, depending on vane exit Mach number. The results are important for future turbines operating with real-gas effects and/or those where high gas temperatures can lead to variations in the isentropic exponent.

References

References
1.
Kouremenos
,
D. A.
, and
Kakatsios
,
X. K.
,
1985
, “
The Three Isentropic Exponents of Dry Steam
,”
Forschung im Ingenieurwesen A
,
51
(
5
), pp.
117
122
. 10.1007/BF02558416
2.
Paradissiadis
,
I.
,
1987
, “
The Three Isentropic Exponents of Wet Steam
,”
Forschung im Ingenieurwesen A
,
53
(
5
), pp.
159
161
. 10.1007/BF02560949
3.
Wheeler
,
A.
, and
Ong
,
J.
,
2013
, “
The Role of Dense Gas Dynamics on ORC Turbine Performance
,”
ASME J. Eng. Gas Turbines Power
,
135
(
10
), p.
102603
. 10.1115/1.4024963
4.
Durá Galiana
,
F. J.
,
Wheeler
,
A.
, and
Ong
,
J.
,
2016
, “
A Study of Trailing-Edge Losses in Organic Rankine Cycle Turbines
,”
ASME J. Turbomach.
,
138
(
12
), p.
121003
. 10.1115/1.4033473
5.
No
,
H. C.
,
Kim
,
J. H.
, and
Kim
,
H. M.
,
2007
, “
A Review of Helium Gas Turbine Technology for High-Temperature Gas-Cooled Reactors
,”
Nucl. Eng. Technol.
,
39
(
1
), pp.
21
30
. 10.5516/NET.2007.39.1.021
6.
Kyprianidis
,
K. G.
,
Sethi
,
V.
,
Ogaji
,
S. O. T.
,
Pilidis
,
P.
,
Singh
,
R.
, and
Kalfas
,
A. I.
,
2011
, “
Uncertainty in Gas Turbine Therm-Fluid Modelling and its Impact on Performance Calculations and Emissions Predictions at Aircraft System Level
,”
Proc. Inst. Mech. Eng., Part G: J. Aerosp. Eng.
,
226
(
2
), pp.
163
181
. 10.1177/0954410011406664
7.
Saravanamutto
,
H. I. H.
,
Rogers
,
G. F. C.
,
Cohen
,
H.
, and
Straznicky
,
P. V.
,
2009
,
Gas Turbine Theory
,
Pearson Education
,
London, UK
.
8.
Rogers
,
G. F. C.
, and
Mayhew
,
Y. R.
,
1992
,
Engineering Thermodynamics: Work and Heat Transfer
,
Pearson
,
New York, NY
.
9.
Dostal
,
V.
,
Hejzlar
,
P.
, and
Driscoll
,
M. J.
,
2006
, “
High-Performance Supercritical Carbon Dioxide Cycle for Next-Generation Nuclear Reactors
,”
Nucl. Technol.
,
154
(
3
), pp.
265
282
. 10.13182/NT154-265
10.
Northall
,
J.
,
2006
, “
The Influence of Variable Gas Properties on Turbomachinery Computational Fluid Dynamics
,”
ASME J. Turbomach.
,
128
(
4
), pp.
632
638
. 10.1115/1.2221324
11.
Srinivasan
,
K.
,
Newman
,
D.
, and
Patil
,
A.
,
2014
, “
Studies on the Impact of Choice of Gas Models in an Un-Cooled Turbine Stage
,” Proceedings of the ASME 2014 Gas Turbine India Conference, GTINDIA2014-8212.
12.
Rubechini
,
F.
,
Marconcini
,
M.
,
Arnone
,
A.
,
Maritano
,
M.
, and
Cecchi
,
S.
,
2008
, “
The Impact of Gas Modeling in the Numerical Analysis of a Multistage Gas Turbine
,”
ASME J. Turbomach.
,
130
(
2
), p.
021022
. 10.1115/1.2752187
13.
Zhang
,
L.
,
Zhang
,
W. Z. Y.
, and
Chen
,
T.
,
2017
, “
Similarity Theory Based Radial Turbine Performance and Loss Mechanism Comparison Between R245fa and Air for Heavy-Duty Diesel Engine Organic Rankine Cycles
,”
Entropy
,
19
(
1
), p.
25
. 10.3390/e19010025
14.
Wheeler
,
A.
, and
Ong
,
J.
,
2014
, “
A Study of the Three-Dimensional Unsteady Real-Gas Flows Within a Transonic Orc Turbine
,” ASME Turbo Expo 2014, GT2014-25475.
15.
Durá Galiana
,
F. J.
,
Wheeler
,
A.
, and
Ong
,
J.
,
2017
, “
The Effect of Dense Gas Dynamics on Loss in ORC Transonic Turbines
,”
J. Phys.: Conf. Ser.
,
821
(1st International Seminar on Non-Ideal Compressible-Fluid Dynamics for Propulsion & Power). 10.1088/1742-6596/821/1/012021
16.
ANSYS
,
2015
. Ansys fluent v17.0 [software].
Technical Report
,
Canonsburg, PA
.
17.
Lemmon
,
E. W.
, and
Span
,
R.
,
2006
, “
Short Fundamental Equations of State for 20 Industrial Fluids
,”
J. Chem. Eng. Data
,
51
(
3
), pp.
785
850
. 10.1021/je050186n
18.
Span
,
R.
, and
Wagner
,
W.
,
2003
, “
Equations of State for Technical Applications. II. Results for Nonpolar Fluids
,”
Int. J. Thermophys.
,
24
(
1
), pp.
41
109
. 10.1023/A:1022310214958
19.
Tillner-Roth
,
R.
, and
Baehr
,
H. D.
,
1994
, “
An International Standard Formulation for the Thermodynamic Properties of 1,1,1,2 Tetrafluoroethane (hfc-134a) for Temperatures From 170 K to 455 K and Pressures Up to 70 MPa
,”
J. Phys. Chem. Ref. Data
,
23
(
5
), pp.
657
729
. 10.1063/1.555958
20.
Lemmon
,
E. W.
,
Huber
,
M. L.
, and
McLinden
,
M. O.
,
2010
,
NIST Standard Reference Database 23: Reference Fluid Thermodynamic and Transport Properties-REFPROP, Version 9.0
,
National Institute of Standards and Technology, Standard Reference Data Program
,
Gaithersburg
.
21.
Arts
,
T.
,
de Rouvriot
,
M. L.
, and
Rutherford
,
A. W.
,
1990
, “
Aero-Thermal Investigation of a Highly Loaded Transonic Linear Turbine Guide Vane Cascade: A Test Case for Inviscid and Viscous Flow Computations
,” Von Karman Institute, Technical Note 174, Technical Report.
22.
Staff
,
A. R.
,
1953
, “
Equations, Tables, and Charts for Compressible Flow
,” NACA Report,
1135
.
23.
Denton
,
J. D.
, and
Xu
,
L.
,
1990
, “
The Trailing Edge Loss of Transonic Turbine Blades
,”
ASME J. Turbomach.
,
112
(
2
), pp.
277
285
. 10.1115/1.2927648
24.
Denton
,
J.
,
1993
, “
The 1993 IGTI Scholar Lecture: Loss Mechanisms in Turbomachines
,”
ASME J. Turbomach.
,
115
(
4
), pp.
621
656
. 10.1115/1.2929299
You do not currently have access to this content.