The exhaust hood of a steam turbine is an important area of turbomachinery research as its performance strongly influences the power output of the last stage blades (LSB). This paper compares results from 3D simulations using a novel application of the nonlinear harmonic (NLH) method with more computationally demanding predictions obtained using frozen rotor techniques. Accurate simulation of exhausts is only achieved when simulations of LSB are coupled to the exhaust hood to capture the strong interaction. One such method is the NLH method. In this paper, the NLH approach is compared against the current standard for capturing the inlet circumferential asymmetry, the frozen rotor approach. The NLH method is shown to predict a similar exhaust hood static pressure recovery and flow asymmetry compared with the frozen rotor approach using less than half the memory requirement of a full annulus calculation. A second option for reducing the computational demand of the full annulus frozen rotor method is explored where a single stator passage is modeled coupled to the full annulus rotor by a mixing plane. Provided the stage is choked, this was shown to produce very similar results to the full annulus frozen rotor approach but with a computational demand similar to that of the NLH method. In terms of industrial practice, the results show that for a typical well designed exhaust hood at nominal load conditions, the pressure recovery predicted by all methods (including those which do not account for circumferential uniformities) is similar. However, this is not the case at off-design conditions where more complex interfacing methods are required to capture circumferential asymmetry.

References

1.
Liu
,
J.
, and
Hynes
,
T. P.
,
2002
, “
The Investigation of Turbine and Exhaust Interactions in Asymmetric Flows: Part 2—Turbine-Diffuser-Collector Interactions
,”
ASME
Paper No. GT2002-30343.10.1115/GT2002-30343
2.
Fu
,
J.-L.
,
Liu
,
J.-J.
, and
Zhou
,
S.-J.
,
2012
, “
Unsteady Interactions Between Axial Turbine and Nonaxisymmetric Exhaust Hood Under Different Operational Conditions
,”
ASME J. Turbomach.
,
134
(
4
), p.
041002
.10.1115/1.4003647
3.
Fan
,
T.
,
Xie
,
Y.
,
Zhang
,
D.
, and
Sun
,
B.
,
2007
, “
A Combined Numerical Model and Optimization for Low Pressure Exhaust System in Steam Turbine
,”
ASME
Paper No. POWER2007-22147.10.1115/POWER2007-22147
4.
Shao
,
S.
,
Deng
,
Q.
,
Shi
,
H.
,
Feng
,
Z.
,
Cheng
,
K.
, and
Peng
,
Z.
,
2013
, “
Numerical Investigation on Flow Characteristics of Low Pressure Exhaust Hood Under Off-Design Conditions for Steam Turbines
,”
ASME
Paper No. GT2013-95259.10.1115/GT2013-95259
5.
Stanciu
,
M.
,
Marcelet
,
M.
, and
Dorey
,
J.-M.
,
2013
, “
Numerical Investigation of Condenser Pressure Effect on Last Stage Operation of Low Pressure Wet Steam Turbines
,”
ASME
Paper No. GT2013-94070.10.1115/GT2013-94070
6.
Verstraete
,
T.
,
Prinsier
,
J.
,
Di Sante
,
A.
,
Della Gatta
,
S.
, and
Cosi
,
L.
,
2011
, “
Design Optimization of a Low Pressure Steam Turbine Radial Diffuser Using an Evolutionary Algorithm and 3d cfd
,”
ASME
Paper No. GT2012-69515.10.1115/GT2012-69515
7.
Stanciu
,
M.
,
Fendler
,
Y.
, and
Dorey
,
J.-M.
,
2011
, “
Unsteady Stator-Rotor Interaction Coupled With Exhaust Hood Effect for Last Stage Steam Turbines
,”
9th European Turbomachinery Conference
, Istanbul, Mar. 21–25, Paper No. B035.
8.
Li
,
Z.
,
Li
,
J.
,
Yan
,
X.
,
Feng
,
Z.
,
Ohyama
,
H.
, and
Zhang
,
M.
,
2012
, “
Investigations on the Flow Pattern and Aerodynamic Performance of Last Stage and Exhaust Hood for Large Power Steam Turbines
,”
ASME
Paper No. GT2012-69291.10.1115/GT2012-69291
9.
Burton
,
Z.
,
Ingram
,
G. L.
, and
Hogg
,
S.
,
2013
, “
The Influence of Inlet Asymmetry on Steam Turbine Exhaust Hood Flow
,”
ASME J. Eng. Gas Turbines Power
,
136
(
4
), p.
042602
.10.1115/1.4026003
10.
Burton
,
Z.
,
Ingram
,
G. L.
, and
Hogg
,
S.
,
2012
, “
A Generic Low Pressure Exhaust Diffuser for Steam Turbine Research
,”
ASME
Paper No. GT2012-68485.10.1115/GT2012-68485
11.
Burton
,
Z.
,
Ingram
,
G. L.
, and
Hogg
,
S.
,
2013
, “
A Generic Steam Turbine Exhaust Diffuser With Tip Leakage Modelling and Non-Uniform Hood Outlet
,”
10th European Turbomachinery Conference
,
Lappeenranta, Finland
, April 15–19, Paper No. ETC10-P38.
12.
Burton
,
Z.
,
Ingram
,
G. L.
, and
Hogg
,
S.
,
2013
, “
Durham Steam Turbine Exhaust Diffuser Test Case
,” School of Engineering and Computing Sciences (ECS), Durham University, Durham, UK, https://www.dur.ac.uk/resources/ecs/research/technical_reports/TR2013_6.pdf
13.
Denton
,
J. D.
, and
Singh
,
U. K.
,
1979
, “
Time Marching Methods for Turbomachinery Flow Calculations
,” Application of Numerical Methods to Flow Calculations in Turbomachines (VKI Lecture Series 1979-7), von Karman Institute, Rhode-Saint-Genese, Belgium.
14.
He
,
L.
, and
Ning
,
W.
,
1998
, “
Efficient Approach for Analysis of Unsteady Viscous Flows in Turbomachines
,”
AIAA J.
,
36
(
11
), pp.
2005
2012
.10.2514/2.328
15.
Vilmin
,
S.
,
Lorrain
,
E.
,
Hirsch
,
C.
, and
Swoboda
,
M.
,
2006
, “
Unsteady Flow Modeling Across the Rotor/Stator Interface Using the Nonlinear Harmonic Method
,”
ASME
Paper No. GT2006-90210.10.1115/GT2006-90210
16.
Purwanto
,
A.
,
Deconinck
,
T.
,
Vilmin
,
S.
,
Lorrain
,
E.
, and
Hirsch
,
C.
,
2011
, “
Efficient Prediction of Nacelle Installation Effects at Take-Off Conditions
,”
9th European Turbomachinery Conference
(
ETC 9
),
Istanbul
, Mar. 21–25.
17.
Fu
,
J.-L.
, and
Liu
,
J.-J.
,
2008
, “
Influences of Inflow Condition on Non-Axisymmetric Flows in Turbine Exhaust Hoods
,”
J. Therm. Sci.
,
17
(
4
), pp.
305
313
.10.1007/s11630-008-0305-5
18.
Hembera
,
M.
,
Loos
,
A.
,
Kahrmann
,
A.
,
Danner
,
F.
,
Kau
,
H.
, and
Johann
,
E.
,
2006
, “
Validation of the Non-Linear Harmonic Approach for Quasi-Unsteady Simulations in Turbomachinery
,”
ASME
Paper No. GT2009-59933.10.1115/GT2009-59933
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