New low pressure (LP), stages for variable speed, mechanical drive and geared power generation steam turbines have been developed. The new blade and nozzle designs can be applied to a wide range of turbine rotational speeds and last stage blade annulus areas, thus forming a family of low pressure stages—High Speed (HS) blades and nozzles. Different family members are exact scales of each other and the tip speeds of the corresponding blades within the family are identical. Thus the aeromechanical and aerodynamic characteristics of the individual stages within the family are identical as well. Last stage blades and nozzles have been developed concurrently with the three upstream stages, creating optimised, reusable low pressure turbine sections. These blades represent a step forward in improving speed, mass flow capability, reliability and aerodynamic efficiency of the low pressure stages for the industrial steam turbines. These four stages are designed as a system using the most modern design tools applied on Power Generation and Aircraft Engines turbo-machineries. The aerodynamic performance of the last three stage of the newly designed group will be verified in a full-scale test facility. The last stage blade construction incorporates a three hooks, axial entry dovetail with improved load carrying capability over other blade attachment methods. The next to the last stage blade also uses a three hooks axial entry dovetail, while the two front stage blades employ internal tangential entry dovetails. The last and next to the last stage blades utilize continuous tip coupling via implementation of integral snubber cover while a Z-lock integral cover is employed for the two upstream stages. Low dynamic strains at all operating conditions (off and on resonance speeds) will be validated via steam turbine testing at realistic steam conditions (steam flows, temperatures and pressures). Low load, high condenser pressure operation will also be verified using a three stage test turbine operated in the actual steam conditions as well. In addition, resonance speed margins of the four stages have been verified through full-scale wheel box tests in the vacuum spin cell, thus allowing the application of these stages to Power Generation applications. Stator blades are produced with a manufacturing technology, which combines full milling and electro-discharge machining. This process allows machining of the blades from an integral disc, and thus improving uniformity of the throat distribution. Accuracy of the throat distribution is also improved when compared to the assembled or welded stator blade technology. This paper will discuss the aerodynamic and aeromechanical design, development and testing program completed for this new low pressure stages family.
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ASME 2007 Power Conference
July 17–19, 2007
San Antonio, Texas, USA
Conference Sponsors:
- Power Division
ISBN:
0-7918-4273-8
PROCEEDINGS PAPER
Design, Manufacturing and Testing of a New Family of Steam Turbine Low Pressure Stages
Jonathon Slepski,
Jonathon Slepski
GE Energy, Schenectady, NY
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Steven DeLessio,
Steven DeLessio
GE Energy, Schenectady, NY
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Michele Taviani,
Michele Taviani
GE Oil&Gas, Florence, Italy
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Amir Mujezinovic´
Amir Mujezinovic´
GE Energy, Schenectady, NY
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Lorenzo Cosi
GE Oil&Gas, Florence, Italy
Jonathon Slepski
GE Energy, Schenectady, NY
Steven DeLessio
GE Energy, Schenectady, NY
Michele Taviani
GE Oil&Gas, Florence, Italy
Amir Mujezinovic´
GE Energy, Schenectady, NY
Paper No:
POWER2007-22056, pp. 313-320; 8 pages
Published Online:
April 21, 2009
Citation
Cosi, L, Slepski, J, DeLessio, S, Taviani, M, & Mujezinovic´, A. "Design, Manufacturing and Testing of a New Family of Steam Turbine Low Pressure Stages." Proceedings of the ASME 2007 Power Conference. ASME 2007 Power Conference. San Antonio, Texas, USA. July 17–19, 2007. pp. 313-320. ASME. https://doi.org/10.1115/POWER2007-22056
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