The Development of High-Performance Leaf Seals

2004 ◽  
Vol 126 (2) ◽  
pp. 342-350 ◽  
Author(s):  
H. Nakane ◽  
A. Maekawa ◽  
E. Akita ◽  
K. Akagi ◽  
T. Nakano ◽  
...  
Keyword(s):  
High Performance ◽  
Combined Cycle ◽  
Point Of View ◽  
Superior Performance ◽  
Air Leakage ◽  
Blade Cooling ◽  
Turbine Performance ◽  
Performance Reduction ◽  
Combined Cycle Plant ◽  
Secondary Air

Recently, from the environmental point of view, demand for a combined cycle plant is increasing, and superior gas turbine performance is being rapidly promoted at the same time. As one of the key technologies for superior performance, reduction of secondary air leakage, which is necessary for blade cooling and bearing sealing, is required. Especially, reduction of air leakage through rotating parts and stationary parts clearance is critical.

The Development of High Performance Leaf Seals

2002 ◽  
Author(s):  
H. Nakane ◽  
A. Maekawa ◽  
E. Akita ◽  
K. Akagi ◽  
T. Shinohara ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Combined Cycle ◽  
Differential Pressure ◽  
Superior Performance ◽  
Hydrodynamic Effect ◽  
Air Leakage ◽  
Brush Seal ◽  
Sealing Performance ◽  
Performance Reduction ◽  
Secondary Air

Recently, from the environmental point of view, demand for combined cycle plant is increasing, and superior gas turbine performance is being rapidly promoted at the same time. As one of the key technologies for superior performance, reduction of secondary air leakage which is necessary for blade cooling and bearing sealing is required. Especially, reduction of air leakage through rotating parts and stationary parts clearance is critical problem. Hitherto, a non-contact type labyrinth seal has been widely used as a seal between rotating parts and stationary parts. However, this seal requires a large clearance to avoid contact, and this causes reduction of performance due to large amount of air leakage. Currently, application of brush seal is rapidly increasing as an improvement, however, a brush seal maintains contact not only at shut down, but also during operation, thereby wear of wire is accelerated during prolong operation, and reducing the sealing performance. In addition, since stiffness of the wire itself is low, differential sealing pressure is also low. In order to overcome these short comings, so-called “Leaf seal” which is MHI’s patent has been developed over the years. Leaf seal has a structure in which multi layered flexible leaves are arranged in the circumferential direction. In this seal, tip of the leaf is lifted up from the rotor surface by the hydrodynamic effect as the rotating speed is accelerated. As a result of this mechanism, wear of the seal is reduced during operation. The clearance generated by the leaf tip lifting up is negligibly small and, therefore, sealing performance is better. Moreover, because the leaf has an axial width, it can endure seal differential pressure several times that of the brush seal. The effect of the leaf lifting up and the leakage air amount were verified by rig tests. After these verification tests, this leaf seal is now being used for M501G gas turbine, installed at *T-point, in order to confirm sealing performance and durability. The leaf seal can sustain high differential pressure even if it is used in single stage, and has very good durability. To conclude it can be said that the leaf seal is the next generation seal replacing the brush seal. * MHI constructed the long-term in-house verification plant known as T-point for verifying new gas turbine technology prior to commercialization. The facility at T-Point consists of a M501G gas turbine, steam turbine, HRSG and associated controls. The output of the M501G gas turbine at T-Point is 225MW.

Advanced Gas Turbine and High Performance Gas-Steam Combined Cycle Plant With Blade Cooling Air Controlling

2006 ◽  
Author(s):  
Tadashi Tsuji
Keyword(s):  
Power Generation ◽  
Heat Exchanger ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Hot Water ◽  
Blade Cooling ◽  
Combined Cycle Plant ◽  
Cooling Air

Air cooling blades are usually applied to gas turbines as a basic specification. This blade cooling air is almost 20% of compressor suction air and it means that a great deal of compression load is not converted effectively to turbine power generation. This paper proposes the CCM (Cascade Cooling Module) system of turbine blade air line and the consequent improvement of power generation, which is achieved by the reduction of cooling air consumption with effective use of recovered heat. With this technology, current gas turbines (TIT: turbine inlet temperature: 1350°C) can be up-rated to have a relative high efficiency increase. The increase ratio has a potential to be equivalent to that of 1500°C Class GT/CC against 1350°C Class. The CCM system is designed to enable the reduction of blade cooling air consumption by the low air temperature of 15°C instead of the usual 200–400°C. It causes the turbine operating air to increase at the constant suction air condition, which results in the enhancement of power and thermal efficiency. The CCM is installed in the cooling air line and is composed of three stage coolers: steam generator/fuel preheater stage, heat exchanger stage for hot water supplying and cooler stage with chilled water. The coolant (chilled water) for downstream cooler is produced by an absorption refrigerator operated by the hot water of the upstream heat exchanger. The proposed CCM system requires the modification of cooling air flow network in the gas turbine but produces the direct effect on performance enhancement. When the CCM system is applied to a 700MW Class CC (Combined Cycle) plant (GT TIT: 135°C Class), it is expected that there will be a 40–80MW increase in power and +2–5% relative increase in thermal efficiency.

Degradation Effects on Combined Cycle Power Plant Performance: Part 1 — Gas Turbine Cycle Component Degradation Effects

2001 ◽  
Author(s):  
A. Zwebek ◽  
P. Pilidis
Keyword(s):  
Gas Turbine ◽  
Combined Cycle ◽  
Plant Performance ◽  
Plant Design ◽  
Turbine Performance ◽  
Fortran Code ◽  
Steam Turbine Plant ◽  
Combined Cycle Plant ◽  
Gas Turbine Exhaust ◽  
Topping Cycle

This paper describes the effects of degradation of the main gas path components of the gas turbine topping cycle on the Combined Cycle Gas Turbine (CCGT) plant performance. Firstly the component degradation effects on the gas turbine performance as an independent unit are examined. It is then shown how this degradation is reflected on a steam turbine plant of the CCGT and on the complete Combined Cycle plant. TURBOMATCH, the gas turbine performance code of Cranfield University was used to predict the effects of degraded gas path components of the gas turbine have on its performance as a whole plant. To simulate the steam (Bottoming) cycle, another Fortran code was developed. Both codes were used together to form a complete software system that can predict the CCGT plant design point, off-design, and deteriorated (due to component degradation) performances. The results show that the overall output is very sensitive to many types of degradation, specially in the turbine of the gas turbine. Also shown is the effect on gas turbine exhaust conditions and how this affects the steam cycle.

scholarly journals Exergy Analysis of Two Second-Generation SCGT Plant Proposals

1998 ◽  
Author(s):  
A. Corti ◽  
L. Failli ◽  
D. Fiaschi ◽  
G. Manfrida
Keyword(s):  
Gas Turbine ◽  
Second Generation ◽  
Combined Cycle ◽  
Point Of View ◽  
Specific Power ◽  
Co2 Removal ◽  
Good Efficiency ◽  
Specific Power Output ◽  
Combined Cycle Plant ◽  
Gas Turbine Exhaust

Two different power plant configurations based on a Semi-Closed Gas Turbine (SCGT) are analyzed and compared in terms of First and Second Law analysis. SCGT plant configurations allow the application of CO2 separation techniques to gas-turbine based plants and several further potential advantages with respect to present, open-cycle solutions. The first configuration is a second-generation SCGT/CC (Combined Cycle) plant, which includes inter-cooling (IC) between the two compression stages, achieved using spray injection of water condensed in a separation process removing vapor from the flue gases. The second configuration (SCGT/RE) combines compressor inter-cooling with the suppression of the heat recovery steam generator and of the whole bottoming cycle; the heat at gas turbine exhaust is directly used for gas turbine regeneration. The SCGT/CC-IC solution provides good efficiency (about 55%) and specific power output figures, on account of the spray inter-cooling; however, with this configuration the cycle is not able to self-sustain the CO2 removal reactions and amine regeneration process, and needs a substantial external heat input for this purpose. The SCGT/RE solution is mainly attractive from the environmental point of view: in fact, it combines the performance of an advanced gas turbine regenerative cycle (efficiency of about 49%) with the possibility of a self-sustained CO2 removal process. Moreover, the cycle configuration is simplified because the HRSG and the whole bottoming cycle are suppressed, and a potential is left for cogeneration of heat and power.

Numerical and Experimental Investigation of Secondary Flows and Influence of Air System Design on Heavy-Duty Gas Turbine Performance

2012 ◽  
Author(s):  
Luca Bozzi ◽  
Enrico D’angelo
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Engine Performance ◽  
Combined Cycle ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Heavy Duty ◽  
Turbine Performance ◽  
Air System ◽  
Secondary Air

High turn-down operating of heavy-duty gas turbines in modern Combined Cycle Plants requires a highly efficient secondary air system to ensure the proper supply of cooling and sealing air. Thus, accurate performance prediction of secondary flows in the complete range of operating conditions is crucial. The paper gives an overview of the secondary air system of Ansaldo F-class AEx4.3A gas turbines. Focus of the work is a procedure to calculate the cooling flows, which allows investigating both the interaction between cooled rows and additional secondary flows (sealing and leakage air) and the influence on gas turbine performance. The procedure is based on a fluid-network solver modelling the engine secondary air system. Parametric curves implemented into the network model give the consumption of cooling air of blades and vanes. Performances of blade cooling systems based on different cooling technology are presented. Variations of secondary air flows in function of load and/or ambient conditions are discussed and justified. The effect of secondary air reduction is investigated in details showing the relationship between the position, along the gas path, of the upgrade and the increasing of engine performance. In particular, a section of the paper describes the application of a consistent and straightforward technique, based on an exergy analysis, to estimate the effect of major modifications to the air system on overall engine performance. A set of models for the different factors of cooling loss is presented and sample calculations are used to illustrate the splitting and magnitude of losses. Field data, referred to AE64.3A gas turbine, are used to calibrate the correlation method and to enhance the structure of the lumped-parameters network models.

Degradation Effects on Combined Cycle Power Plant Performance—Part I: Gas Turbine Cycle Component Degradation Effects

2003 ◽  
Vol 125 (3) ◽  
pp. 651-657 ◽  
Author(s):  
A. Zwebek ◽  
P. Pilidis
Keyword(s):  
Gas Turbine ◽  
Combined Cycle ◽  
Plant Performance ◽  
Plant Design ◽  
Turbine Performance ◽  
Fortran Code ◽  
Steam Turbine Plant ◽  
Combined Cycle Plant ◽  
Gas Turbine Exhaust ◽  
Topping Cycle

This paper describes the effects of degradation of the main gas path components of the gas turbine topping cycle on the combined cycle gas turbine (CCGT) plant performance. First, the component degradation effects on the gas turbine performance as an independent unit are examined. It is then shown how this degradation is reflected on a steam turbine plant of the CCGT and on the complete combined cycle plant. TURBOMATCH, the gas turbine performance code of Cranfield University, was used to predict the effects of degraded gas path components of the gas turbine have on its performance as a whole plant. To simulate the steam (bottoming) cycle, another Fortran code was developed. Both codes were used together to form a complete software system that can predict the CCGT plant design point, off-design, and deteriorated (due to component degradation) performances. The results show that the overall output is very sensitive to many types of degradation, especially in the turbine of the gas turbine. Also shown is the effect on gas turbine exhaust conditions and how this affects the steam cycle.

scholarly journals Efficient District Heat Production by Heat Extraction From Combined Cycle Plants

1996 ◽  
Author(s):  
H. Haselbacher ◽  
H. U. Frutschi
Keyword(s):  
Heat Production ◽  
District Heating ◽  
Combined Cycle ◽  
Point Of View ◽  
Heat Extraction ◽  
Important Conclusion ◽  
Combined Cycle Plant ◽  
Two Alternatives

Among cogeneration facilities block heating stations and large combined cycle plants are two extreme examples of district heating technologies. In this paper, these two alternatives will be applied to one and the same representative district heating task. The thermodynamic differences will be made clear and the advantages of heating by extracting steam from a combined cycle plant will become evident. An important conclusion from an engineering point of view is that extracting heat from a combined cycle plant should be considered even if this plant is located at greater distances from the heat consumers.

Efficient District Heat Production by Heat Extraction From Combined Cycle Plants

1997 ◽  
Vol 119 (4) ◽  
pp. 898-902
Author(s):  
H. Haselbacher ◽  
H. U. Frutschi
Keyword(s):  
Heat Production ◽  
District Heating ◽  
Combined Cycle ◽  
Point Of View ◽  
Heat Extraction ◽  
Important Conclusion ◽  
Combined Cycle Plant ◽  
Two Alternatives

Among cogeneration facilities, block heating stations and large combined cycle plants are two extreme examples of district heating technologies. In this paper, these two alternatives will be applied to one and the same representative district heating task. The thermodynamic differences will be made clear and the advantages of heating by extracting steam from a combined cycle plant will become evident. An important conclusion from an engineering point of view is that extracting heat from a combined cycle plant should be considered even if this plant is located at greater distances from the heat consumers.

Sign in / Sign up

Export Citation Format

Share Document