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1
Recent Advances in Ultra Super Critical
Steam Turbine Technology
M. Boss T. Gadoury S. Feeny M. Montgomery
GE Energy, Steam Turbine Technology
1 River Road, Schenectady, NY 12345
Abstract – With the continuing drive to reduce power plant emissions including green
house gases, coal fired power plants have been moving to higher ultra-supercritical (USC) steam
conditions in addition to advances in technology. GE Energy has designed the next generation USC
steam turbine generator with a rating of 1000 MW to address the need for higher efficiency coal
fired power plants. With inlet steam conditions of 260 bar and 610ºC / 621ºC (3770 psi and 1150F /
1180F), the primary objective for the advanced technology USC 1000 MW steam turbine is high
efficiency. To achieve this higher cycle efficiency, the design utilizes advanced steam turbine
technology and system design and a longer last stage bucket design in addition to ultra
supercritical steam conditions.
Performance enhancing technology is being applied to turbine buckets, nozzles and seals.
In addition to improvements to steam path components, performance gains are achieved by
optimizing stationary components such as valves, inlets, and exhausts using advanced CFD tools.
This USC project illustrates the latest design and technology capabilities of GE Energy and
sets the standard for future 1000 MW USC applications.
1. INTRODUCTION
GE Energy was an early entrant into USC steam turbine technology with the first unit
shipped in 1956 with inlet steam conditions of 310 bar / 621C (4500 psi / 1150F). Since then, GE
has shipped 77GW of steam turbines (125 units) with supercritical steam conditions. GE designed
the world’s most powerful USC steam turbine rated 1050 MW operating at 250 bar / 600C / 610C
(3626 psi / 1112F / 1130F). This 1000 MW USC steam turbine design is a natural evolution of GE’s
USC technology. GE continues to develop and refine USC steam turbine technology.
With the emerging interest in reducing emissions, including green house gases from coal
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fired power generation, GE Energy is striving to increase USC PC generation output and efficiency in
its development of this 1000MW USC PC platform. Every 1% improvement in plant efficiency results
in approximately 2.5% reduction in green house gas emissions. To satisfy this objective, GE Energy
is looking to achieve the following advances in PC generation technologies:
MW rating: 1000MW MGR
HP throttle pressure: 260 bar (3770 psi)
HP throttle temperature: 610C (1130F)
Reheat steam temperature: 621C (1150F)
Condenser pressure: 1.5” Hg (NR Back Pressure: 2.5” Hg)
4 flow, 45 inch Last Stage Blade
Cycle: Single Reheat Regenerative
2. TECHNOLOGY of USC STEAM TURBINE
2.1 Cycle Overview
In the evaluation of steam conditions, the potential cycle efficiency gain from elevating
steam pressures and temperatures must be considered. Starting with the traditional 165 bar /
538°C (2400 psi / 1000°F) single reheat cycle, dramatic improvements in power plant performance
can be achieved by raising inlet steam conditions to levels up to 310 bar (4500 psi) and
temperatures to levels in excess of 600°C (1112°F). Every 28°C (50°F) increase in throttle and reheat
temperature results in approximately 1.5% improvement in heat rate.
The feedwater heater arrangement is designed to obtain the best heat rate for a given set
of USC steam conditions. In general, the selection of higher steam conditions will result in additional
feedwater heaters and a higher final feedwater temperature. The higher final feedwater
temperature will have an impact on the boiler cost. This then requires a system level optimization to
determine the best economical solution for the increase in final feedwater temperature. In many
cases, the selection of a heater above the reheat point (HARP) also is warranted. The use of a
separate de-superheater ahead of the top heater for units with a HARP can result in additional
gains in unit performance.
The selection of the cold reheat pressure is an integral part of any power plant design, but
becomes even more important for plants with advanced steam conditions. Comparing the heat rate
at the thermodynamic optimum, the improvement resulting from the use of a HARP can be about
0.6%. However, economic considerations of the boiler design without a HARP tend to favor a lower
reheater pressure at the expense of a slight decrease in cycle performance. The resulting net heat
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rate gain is usually larger, approaching 0.6-0.7%. Changing the final feedwater temperature, adding
a HARP, and setting the reheater pressure obtain the best relative heat rate impact.
The use of advanced reheat steam conditions strongly affects the inlet temperature to the
low-pressure (LP) turbine section. An increase in hot reheat temperature translates into an almost
equal increase in crossover temperature for a given crossover pressure. However, the maximum
allowable LP inlet temperature is limited by material considerations associated with the rotor,
crossover and hood stationary components. In addition, the selection of hot reheat temperature
(and corresponding effect on LP inlet temperature) impacts the amount of moisture at the L-0
bucket which factors into stress corrosion cracking considerations.
Once the reheat steam conditions are established (pressure and temperature) then the LP
steam conditions can be determined. If the resulting crossover temperature is too high, the energy
ratio between the IP and the LP can be changed to lower this temperature. Increasing the energy on
the IP section will lower the crossover temperature, but it will also impact the cycle efficiency,
increase the number of IP stages, or the loading of the IP stages, increase the height of the final IP
bucket, increase the size of the crossover, or increase the pressure drop through the crossover.
2.2 Steam Turbine Configuration
The appropriate steam turbine configuration for a given USC application is largely a
function of the number of reheats selected, the unit rating, the site back pressure characteristics,
and any special requirements such as district heating extractions. Specific design details will also
determine the number of flows in a turbine section, the number of stages and the last stage bucket
(LSB) length.
In particular, the site ambient conditions and the condensing system will play a huge role in
the selection of the LSB and the number of LP section flows. The 38.1 mmHgA (1.5” HgA) would be
for a direct cooled condenser, or cooling towers in a cold environment. The 88.9 mmHgA (3.5” HgA)
would be for cooling towers in an area with warmer ambient temperatures.
The expected exhaust pressure of the plant at the time of maximum expected power
production should be considered in the design the LP section. At 1.5” HgA, and 1000 MW output, a
45” LSB and a 6-flow LP section would achieve the best heat rate. At 3.5”HgA, and an output of
1000 MW, the 40” LSB, and a 4-flow LP section would be the lowest heat rate choice. In either of
these cases, the high pressure (HP) and intermediate pressure (IP) sections would be essentially the
same.
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The turbine cost increases and plant cost increases would then be compared to the
expected kilowatt outputs to optimize the plant Cost of Electricity. In the case of the 3.5” HgA, the 4-
flow 40” would be higher cost than the 4-flow 33.5”, and the footprint of the 40” LP section would be
larger also. In the case of the 1.5” HgA chart, the 6-flow LP section would require the additional LP
turbine section, and additional condenser, as well as a larger footprint for the 45” LP section.
These considerations resulted the selection of a 4-flow 45” LP section design. The overall
turbine configuration is shown in Figure 1.
Figure 1 - 4-casing, 4-flow LP Configuration
2.3 Evaluation of Ultra Super Critical Technology
The history of steam turbine development is an evolutionary advancement toward greater
power density and efficiency. Improvements in the power density of steam turbines have been
driven largely by the development of improved rotor and bucket alloys as well as improvements in
the design and analysis of the attachment devices for the vanes. This has increased the allowable
stresses and enabling the construction of longer last stage buckets for increased exhaust area per
exhaust flow.
Increases in efficiency have been achieved largely through two kinds of advancements: (1)
improving expansion efficiency by reducing aerodynamic and leakage losses as the steam expands
through the turbine; and (2) improving the thermodynamic efficiency by increasing the temperature
and pressure at which heat is added to the power cycle. The latter improvement is the core of USC
technology.
The design of the Ultra Super Critical steam turbine for the present development will
incorporate the new technologies, which consist of:
© 2007, General Electric Company
5
i) Improvement of in the power density of steam turbines such as;
Increased number of stages
Decreased inner ring diameter
Optimized stage reaction levels
Optimized Stage energy levels
ii) Mechanical design elements including:
Advanced sealing
Integral cover bucket (ICB)
Full Arc, hook diaphragm 1st stage
Advanced cooling scheme
iii) Improved HP/IP/LP shell design
iv) Advanced LP design with 45 inch last stage blade
3. HIGH/INTERMEDIATE PRESSURE TURBINE DESIGN
3.1 High Pressure (HP) Section Design
3.1.1 Section Design
Figure 2 shows the HP cross-section. The HP section is designed in a single flow
configuration. This modern design eliminated the partial admission, control stage, and nozzle box.
An overload admission was added for frequency control and capacity margin. Main steam enters
the section through two pipes (top and bottom.) A heater above reheat point extraction is taken
from the lower half. The HP exhaust uses two cold-reheat (CRH) pipes from the lower half
arranged in the pant leg configuration. Elimination of the nozzle box required that two inner shells
be used. All shells are split and bolted at their horizontal joints for ease of maintenance. In this
arrangement, the inlet #1 inner shell is subject to adjacent stage steam conditions on its inner
surfaces and a downstream stage’s steam pressure on its outer surface. The corresponding outer
shell inner surface is subjected to steam conditions at the same downstream steam pressure, albeit
with an enthalpy determined by the flow balance of steam between the packing leakage and the
split location. The exhaust #2 inner shell is arranged in a manner similar to that for the full inner
shell described above. The inner shell split location is judiciously chosen to optimize the horizontal
joint and bolting design of the outer, #1 inner, and #2 inner shells. The outer and # 1 inner shell are
cast 10Cr material. The #2 inner shell is cast CrMoV material. The mono-block rotor material is 12Cr.
The Advancing steam conditions necessitated the addition of inlet cooling for the rotating parts to
allow the rotor design to stay 12Cr materials. Full admission design alleviated the mechanical
challenges associated with partial admission design and the control stage. Thrust is balanced using
the pressure difference across the rotor at the generator end of the HP section. The rotor is
supported by bearings in the front and middle standards. Both standards slide in a manner
6
conventional to GE 4 casing, 4-flow turbine construction.
Figure 2 - HP Section Arrangement
3.1.2 High Pressure Steam Path
The HP steam path has 10 stages. The first stage is full-arc admission. The HP staging is
designed in a manner typical for GE’s proven designs using Dense PackTM steampath components.
The buckets of the first four stages are made of nickel-based material due to the high temperature
creep requirements. The remaining buckets are conventional 12Cr materials. All 10 stages will utilize
integral cover buckets (ICB) with advanced tip seals. Figure 3 shows a typical GE ICB design. The
wheel spaces of the first two stages are cooled using external cooling steam. The first five stages of
diaphragms utilize 10Cr materials. The remaining five stages of diaphragms use 12Cr web and ring
material. A combination of brush, variable clearance, and conventional shaft seals are used in the
HP section.
Figure 3 - Typical GE ICB Design
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3.2 Intermediate Pressure (IP) Section
3.2.1 Section Design
Figure 4 shows the intermediate-pressure cross-section. The IP section is designed in a
double flow configuration. Steam enters the section through two pipes in the lower half. Two feed
water heater extractions are taken from the lower half. The IP exhaust uses two cross over
connections from the upper half arranged in the manner conventional to GE 4 casing, 4-flow
turbine construction. Single shell construction is used. The shell is split and bolted at its horizontal
joint to minimize clearances and reduce manufacturing cost. The shell is cast 10Cr material. The
mono-block rotor material is 12Cr. The advancing steam conditions necessitated the addition of
inlet cooling for the rotating parts. The rotor is supported by bearings in the middle standard and
LPA standards. Both standards slide in a manner conventional to GE 4 casing, 4-flow turbine
construction.
Figure 4 - IP Section Arrangement
3.2.1 Steam Path Design
The IP steam path has 8 stages. The IP staging is designed in a manner typical for GE’s
proven designs using Dense PackTM components. The buckets of the first three stages are made of
nickel-based material due to high temperatures. The remaining buckets are conventional 12Cr
materials. All 8 stages will utilize integral cover buckets (ICB) with advanced tip seals. The wheel
spaces of the first two stages are cooled using cooling steam, from HP section. The first two stages
of diaphragms utilize 10Cr materials. The remaining six stages of diaphragms use 12Cr web and
ring material. A combination of variable clearance and conventional shaft seals are used in the IP
section.
3.3 Aerodynamic Design
3.3.1 Advanced Aero Design
© 2007, General Electric Company
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The biggest advance in steam turbines in recent years has been Aerodynamics. GE has
continued to develop advanced aerodynamic vane shapes based on 100 years of experience
coupled with 3D CFD (computational fluid dynamics) and GE’s HP test facility. The addition of CFD in
the last 10-15 years has resulted in great strides in steam turbine aerodynamics. Figure 5 shows the
evolution of aerodynamic shapes over the years.
Stea
m P
ath
Effic
ienc
y %
Free -Vortex• Uniform Radial
Controlled -Vortex• Non -Uniform Radial Flow• Straight Trailing Edge
Advanced -Vortex• Compound Lean • Bowed Nozzle
Partitions
1960’sFree -
VortexDesign
1970’sIm proved
Vane Profiles
1980’sControlVortexDesign
1990’sAV1, adv
RTSS
Late 1990’sAV2, ICBs,
opt. clearance
2000’sDense Pack
2000’sDense Pack ™
w/adv sealing
Free -Vortex• Uniform Radial
Flow
Controlled- Vortex• Non Uniform Radial Flow• Straight Trailing Edge• Optimized Reaction
Advanced - Vortex• Compound Lean • Bowed Nozzle
Partitions
-
Stea
m P
ath
Effic
ienc
y %
Free -Vortex• Uniform Radial
Controlled -Vortex• Non -Uniform Radial Flow• Straight Trailing Edge
Advanced -Vortex• Compound Lean • Bowed Nozzle
Partitions
1960’sFree -
VortexDesign
1970’sIm proved
Vane Profiles
1980’sControlVortexDesign
1990’sAV1, adv
RTSS
Late 1990’sAV2, ICBs,
opt. clearance
2000’sDense Pack
2000’sDense Pack ™
w/adv sealing
Free -Vortex• Uniform Radial
Flow
Controlled- Vortex• Non Uniform Radial Flow• Straight Trailing Edge• Optimized Reaction
Advanced - Vortex• Compound Lean • Bowed Nozzle
Partitions
- New Design
Adv Sealing
Stea
m P
ath
Effic
ienc
y %
Free -Vortex• Uniform Radial
Controlled -Vortex• Non -Uniform Radial Flow• Straight Trailing Edge
Advanced -Vortex• Compound Lean • Bowed Nozzle
Partitions
1960’sFree -
VortexDesign
1970’sIm proved
Vane Profiles
1980’sControlVortexDesign
1990’sAV1, adv
RTSS
Late 1990’sAV2, ICBs,
opt. clearance
2000’sDense Pack
2000’sDense Pack ™
w/adv sealing
Free -Vortex• Uniform Radial
Flow
Controlled- Vortex• Non Uniform Radial Flow• Straight Trailing Edge• Optimized Reaction
Advanced - Vortex• Compound Lean • Bowed Nozzle
Partitions
-
Stea
m P
ath
Effic
ienc
y %
Free -Vortex• Uniform Radial
Controlled -Vortex• Non -Uniform Radial Flow• Straight Trailing Edge
Advanced -Vortex• Compound Lean • Bowed Nozzle
Partitions
1960’sFree -
VortexDesign
1970’sIm proved
Vane Profiles
1980’sControlVortexDesign
1990’sAV1, adv
RTSS
Late 1990’sAV2, ICBs,
opt. clearance
2000’sDense Pack
2000’sDense Pack ™
w/adv sealing
Free -Vortex• Uniform Radial
Flow
Controlled- Vortex• Non Uniform Radial Flow• Straight Trailing Edge• Optimized Reaction
Advanced - Vortex• Compound Lean • Bowed Nozzle
Partitions
- New Design
Adv Sealing
Figure 5 - Evolution of Steam Turbine Aerodynamics
GE’s designs using Dense PackTM components further improve efficiency by addressing the
major sources or aerodynamic loss in impulse steam turbines. This is achieved via:
Higher bucket reaction -> Decreased nozzle velocity/turning ->Decreased nozzle profile and
secondary losses
Reduced nozzle and bucket counts -> Decreased friction loss
Decreased root diameter -> Increase bucket active length -> Improved bucket efficiency
In addition, the higher reaction and decreased root diameter result in additional stages (in
order to keep optimum wheel velocity ratio). These additional stages improved section efficiency.
3.3.2 High Pressure Turbine 1st Stage
Older steam turbine designs utilized a control stage to control pressure and load during
transient conditions. The mechanical design requirements of this stage, having to withstand partial
arc stimulus, often result in a very large and in-efficient 1st stage design that can be 5-10% lower
© 2007, General Electric Company
9
efficiency than the other HP stages. Although there have been many improvements to control stage
design in recent years as part of GE’s products using Dense PackTM components, the efficiency still
lags other group stages. Therefore, for this 1000 MW USC standard GE chose to implement a full arc
1st stage design, which is much higher reaction and lower aspect ratio to a traditional control stage.
This enables the first stage design to rival the efficiency of other stages. To allow this however,
changes need to be made to allow the turbine to quickly and efficiently respond to load swings.
Therefore, GE will utilize an overload valve that will bypass the 1st stage and allow additional
flow/load response. GE has utilized such a design previously, and has a patent in this area.
3.3.3 High Pressure and Intermediate Pressure Cooling
As throttle temperatures increase, cooling becomes extremely important. For this 1000 MW
USC standard, GE utilizes traditional type IP Cooling, and also HP cooling, which was utilized on GE’s
1st USC machine in 1958. HP cooling takes lower enthalpy steam from the boiler and floods the HP
1st stage wheel and N2 packing areas. This method has minimal performance penalty since lower
enthalpy steam feeds the leakage circuit and the high enthalpy steam stays in the steampath. In
addition, the IP cooling steam is mixed from 2 different sources, allowing better control of
temperature, and minimizing flow and performance loss.
4. LOW PRESSURE TURBINE DESIGN TECHNOLOGY
4.1 Wheel and Diaphragm Configuration Structure
Figure 6 - Wheel and Diaphragm Configuration
As shown in Figure 6, the LP design for the 1000 MW consists of 5 stages with 4 extractions
for the feed water cycle. The last 3 stages (L-0, L-1, and L-2) are designed as a system and the L-0
utilizes the new GE 45” Titanium LSB design. This provides the maximum annulus area for a 4-flow
© 2007, General Electric Company
10
configuration. Titanium material is required due to the large load. In addition, advanced curved
axial entry dovetails have been developed to minimize stresses. High strength LP rotor material,
similar to that used on GE’s 40” steel bucket is also used to control stress.
The first 2 LP stages (L-3 and L-4) utilize high reaction stage design for optimal efficiency. In
addition, advance brush seals are utilized to reduce leakage losses.
4.2 Exhaust Hood Design
The LP turbine section is a complex system, which requires a careful optimization, to get
the proper balance of performance, cost, robust operability, and ease of maintenance. The
elements of this LP turbine section are: the outer exhaust hood, the inner casing, the stationary
steam path, and the rotor.
As the steam paths get larger, with the introduction of longer last stage buckets, the
challenges of the exhaust hood design become more critical. The exhaust hood must contain the
vacuum established in the condenser, it must support the rotor bearings, as well as the inner casing,
and it must have a design that allows for the proper diffusion of the steam leaving the last stage.
Three-dimensional (3D) solid models of all of the components of the LP turbine allow for
state-of-the-art analysis techniques, with respect to finite stress calculations, transient heat
transfer calculations, component response to heating and loading, and Computational Fluid
Dynamic (CFD) Analysis. The critical movements of the interfaces of the various components need to
be understood to be able to optimize the clearance calculation throughout the LP turbine. The
required axial and radial clearances can be calculated with the transient loading conditions for
start-up and shut down of the machine. This together with a statistical analysis on the expected
variation from the stack-up, manufacturing tolerances, and calculation uncertainty, yields the
clearances for the machines. Figure 7 shows the exhaust hood outer model, which is a part of this
analysis.
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Figure 7 - LP Exhaust Hood Model
The LP exhaust hood directs the flow from the last stage bucket exit annulus to the condenser. The
high volumetric flows associated with the low exhaust pressure result in high exit Mach numbers
making the recovery of this exit kinetic energy or “Leaving Loss” an important feature of the LP
turbine. To maximize the recovery of the exit kinetic energy, the exhaust hood is designed using an
unstructured CFD mesh. Inlet boundary conditions are set to model the effects of the LSB exit flow
profile.
Results of this model, shown in Figure 8, are used to refine the geometric definition of the
exhaust hood shape such that the flow losses are reduced and the leaving loss is recovered to the
maximum extent possible. In the exhaust, the placement and shapes of the butterfly plates, Herzog
plates, and steam guides were designed for the best performance. These changes reduced the high
velocity regions, minimized separations, and reduced flow turning resulting in reduced inlet and
exhaust pressure losses, contributing to the overall improved performance of the LP turbine.
Figure 8 -LP casing Model and CFD results
© 2007, General Electric Company
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The LP inner casing inlet duct transitions flow from the crossover pipe to the annular inlets
of the steam path. 3D CFD analysis of the inlet region is employed to minimize the losses during this
transition. Results from this analysis provided the inlet boundary condition for the turbine analysis,
including both radial and circumferential variation.
4.3 LP Inlet Design
In addition to the CFD work used to optimize LP Exhaust, similar methods are used for LP
Inlets. Although the velocities are much lower in the inlets, meaning that less performance is lost
than in the exhaust, some improvements can be made. Aside from the basic area rules of crossover
to LP inlet to 1st stage used to avoid acceleration, the LP inlet shape can be designed to reduce
pressure drop. Figure 9 shows a CFD analysis of an LP inlet before and after aerodynamic
optimization. The colors represent areas of different velocity. (red is high, blue is low)
Figure 9 - LP Inlet Optimization
5. ADVANCED SEAL DESIGN TECHNOLOGY
One of the biggest issues with increased reaction is the need for improved seals over the
bucket tips due to the higher pressure drops. To further efficiency improvements, improved seals
are also applied to diaphragms. GE’s wheel and diaphragm construction lends itself well to
application of a variety of advanced seals.
5.1 Elliptical Clearance Packing
© 2007, General Electric Company
13
The first, most basic advanced seal used is a standard hi-lo or slant tooth packing with
elliptical packing. Elliptical packing has been shown through experience to be the best solution to
minimize leakage area while preventing most rubs. Clearances tend to be larger at the vertical
position as opposed to the horizontal position due to rotor and stationary part movements. Recent
CFD analyses as well as component testing has shown that rubbed packing shapes have a much
higher leakage than a sharp toothed packing (see Figure 10).
Figure 10 - Rubbed packing CFD
Elliptical clearances are used in conjunction with other advanced seals in most areas.
5.2 Variable Clearance Positive Pressure Packing
In the 1990’s GE introduced its proprietary variable clearance positive pressure packing
(VCPPP). This design provides improved rub resistance, as the packing is “open” while the turbine is
starting up. Unlike conventional packing where the spring pushes the packing ring toward the rotor,
the spring on VCPPP packing pushed the ring away from the rotor by a prescribed amount. Once
the turbine starts to increase in load, pressure builds up and “closes” the ring against the hook. This
is beneficial as the rotor has already gone through its critical speeds and much of the thermal
transient conditions that lead to rubbing have passed. GE applies VCPPP where pressure drops are
large enough to close the rings.
5.3 Brush Seals
Brush seals have been used in GE steam turbines since the 1990’s and have proven to be
very beneficial. Brush seals, unlike traditional packing, are design to contact during normal
operation. The “bristle” material is designed for heavy wear, thus resulting in a minimal clearance
during the life of the turbine. Brush seals are most effective where there are large pressure drops,
however there is some limitation on pressure drop based on backplate stress. Brush seal usage is
© 2007, General Electric Company
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also limited based on rotor dynamics criteria. Since the seals are designed to rub, there is heat
generation in the rotor locally to the rub. This rub causes a thermal bow that can cause rotor
instability. Therefore, brush seals are limited in number, based on the rotor dynamics characteristics
of a given rotor.
6. CONCLUSIONS
GE Energy’s next generation 1000 MW fossil PC steam turbine generator platform provides
increased efficiency and reduction in emissions, which is of paramount importance to the
environment. USC steam conditions enable high efficiency designs that reduce the amount of fuel
required for generation and reduce green house gas emissions.
REFERENCES
1. J. Michael Hill, Sanjay Goel, “Development of the Dense Pack Steam turbine: A New Design
Methodology for Increased Efficiency”, Proceedings of 2000 International Joint Power
Generation Conference, 2000
2. Eichiro Watanabe, Yoshinori Tanaka, “Development of New High Efficiency Steam Turbine”,
Mitsubishi Heavy Industries, Ltd., Technical Review Vol. 40 No.4., Aug. 2003
3. Tom Logan, Un-Hak Nah, James Donohue, “GE and Doosan bring Ultra Super Critical Steam
Turbine Technology to Korea”, Proceedings of 2003 Power Gen Asia, 2003.
4. Daniel Cornell, Klaus Retzlaff, Sean Talley, “DX2 (Dense Pack) Steam Turbines”, GER-4202 GE
Power Systems.
5. Mujezinovic, A., Hofer, D., Barb, K., Kaneko, J, Tanuma, T. and Okuno, K, “Introduction of 40/48
Inch Steel Steam Turbine Low Pressure Section Stages”, Proceeding of the Power-GEN Asia,
(2002), CD-ROM.
6. Hofer, D., Slepski, J., Tanuma, T. Shibagaki, T., Shibukawa, N., and Tashima, T., “Aerodynamic
Design and Development of Steel 48/40 inch Steam Turbine LP End Bucket Series”, Proceedings
of the International Conference on Power Engineering-03 (ICOPE-03) November 9-13, 2003,
Kobe, Japan
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