scholarly journals Performance Modeling and Analysis of a Single-Shaft Closed-Cycle Gas Turbine Using Different Operational Control Strategy

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Emmanuel O. Osigwe ◽  
Arnold Gad-Briggs ◽  
Dodeye Igbong ◽  
Theoklis Nikolaidis ◽  
Pericles Pilidis
Keyword(s):  
Gas Turbine ◽  
Control Strategy ◽  
Nuclear Reactor ◽  
High Efficiency ◽  
Control Strategies ◽  
Operating Conditions ◽  
Cycle Performance ◽  
Closed Cycle ◽  
Independent Control ◽  
Modeling And Analysis

Abstract In the last few years, one considerable factor for the viability and interest in the closed-cycle gas turbine (GT) systems for nuclear or conventional power plant application is its potential to maintain high cycle performance at varying operating conditions. However, for this potential to be realized, more competitive analysis and understanding of its control strategy are importantly required. In this paper, the iterative procedure for three independent control strategies of a 40 MW single-shaft intercooled-recuperated closed-cycle GT incorporated to a generation IV nuclear reactor is been analyzed and their performance at various operating conditions compared. The rationale behind this analysis was to explore different control strategies and to identify potential limitations using each independent control. The inventory control strategy offered a more viable option for high efficiency at changes in ambient and part-load operations, however, operational limitations in terms of size and pressure of inventory tank, rotational speed for which the centrifugal forces acting on the blade tips could become too high, hence would affect the mechanical integrity and compressor performance. The bypass control responds rapidly to load rejection in the event of loss of grid power. And more interestingly, the results showed the need for a mixed or combined control instead of a single independent technique, which is limited in practice due to operational limits.

scholarly journals Development of the PGT 25 High Efficiency Gas Turbine: Part 2 — Aerodynamic Design and Performance

1984 ◽  
Author(s):  
E. Benvenuti ◽  
B. Innocenti ◽  
R. Modi
Keyword(s):  
Gas Turbine ◽  
High Efficiency ◽  
Performance Testing ◽  
Operating Conditions ◽  
Aerodynamic Design ◽  
Direct Drive ◽  
Gas Generator ◽  
Full Load ◽  
Wide Range ◽  
Overall Performance

This paper outlines parameter selection criteria and major procedures used in the PGT 25 gas turbine power spool aerodynamic design; significant results of the shop full-load tests are also illustrated with reference to both overall performance and internal flow-field measurements. A major aero-design objective was established as that of achieving the highest overall performance levels possible with the matching to latest generation aero-derivative gas generators; therefore, high efficiencies were set as a target both for the design point and for a wide range of operating conditions, to optimize the turbine’s uses in mechanical drive applications. Furthermore, the design was developed to reach the performance targets in conjunction with the availability of a nominal shaft speed optimized for the direct drive of pipeline booster centrifugal compressors. The results of the full-load performance testing of the first unit, equipped with a General Electric LM 2500/30 gas generator, showed full attainment of the design objectives; a maximum overall thermal efficiency exceeding 37% at nominal rating and a wide operating flexibility with regard to both efficiency and power were demonstrated.

scholarly journals An Introduction Into the Clearance Management of Ansaldo GT36 From Development to Validation

2018 ◽  
Author(s):  
S. Boeller ◽  
B. Feuillard ◽  
G. Filkorn ◽  
S. Olmes ◽  
F. Prou ◽  
...  
Keyword(s):  
Gas Turbine ◽  
High Efficiency ◽  
Evaluation Process ◽  
3D Models ◽  
Operating Conditions ◽  
Active Management ◽  
Test Plant ◽  
Pinch Point ◽  
Load Range ◽  
Clearance Prediction

The optimization and evaluation of blading clearance is important for gas turbine efficiency and performance. The Ansaldo GT36 gas turbine offers high efficiency together with outstanding flexibility across a large load range. Active management of engine clearances during the complete development process followed by a thorough validation on the Ansaldo test plant facility in Birr, Switzerland enables the GT to attain ambitious clearance targets. The clearance at baseload must be minimized but is limited by the pinch point clearance during cold, warm and hot start-ups — including normal and fast ramp-up and/or shutdown. Therefore transient analysis is necessary for covering the different operating conditions. A well-established process of 2d finite element modelling of the whole engine model (WEM) comprised of axis-symmetric and plane stress elements was used during the design process from concept to detailed design to optimize the clearances. It delivers the transient stator and rotor deformation and together with the compressor and turbine airfoil deformation based on 3D models the basic clearance evaluation process is defined. The GT engine design was significantly influenced, starting with a simplified version of the WEM for identification of the most promising variants. Subsequently a detailed WEM was developed which is fully validated against measurements on the test engine. Different 3D effects are considered separately at identified critical transient conditions and overlaid on the 2d clearances which lead to the final optimized clearances. In addition to this, limitations from each step of the manufacturing process were identified and improved to reduce tolerances and uncertainties to their minimum. The results of the calculation and clearance prediction process are compared against clearance measurements during all kinds of GT operation and cooldown. Passive clearance indicators showing the remaining gap till rubbing would occur and rub marks, in areas that tolerate it, further validate the clearances and clearance prediction process.

The Nuclear Gas Turbine: Towards Realization After Half a Century of Evolution

1995 ◽  
Author(s):  
Colin F. McDonald
Keyword(s):  
Power Systems ◽  
Gas Turbine ◽  
Nuclear Reactor ◽  
Electrical Power ◽  
District Heating ◽  
Small Scale ◽  
Closed Cycle ◽  
Furnace Gases ◽  
The Usa ◽  
Space Power Systems

This paper has been written exactly 50 years after the first disclosure of a closed-cycle gas turbine concept with a simplistic uranium heater. Clearly, this plant was ahead of its time in terms of technology readiness, and the closed-cycle gas turbine was initially deployed in a cogeneration mode burning dirty fuels (e.g., coal, furnace gases). In the 1950s through the mid 1980s about 20 of these plants operated providing electrical power and district heating for European cities. The basic concept of a nuclear gas turbine plant was demonstrated in the USA on a small scale in 1961 with a mobile closed-cycle nitrogen gas turbine [330 KW(e)] coupled with a nuclear reactor. In the last three decades, closed-cycle gas turbine research and development, particularly in the U.S. has focused on space power systems, but today the utility size gas turbine-modular helium reactor (GT-MHR) is on the verge of being realized. The theme of this paper traces the half century of closed-cycle gas turbine evolution, and discusses the recent enabling technologies (e.g., magnetic bearings, compact recuperator) that now make the GT-MHR close to realization. The author would like to dedicate this paper to the late Professor Curt Keller who in 1935 filed the first closed-cycle gas turbine patent in Switzerland, and who exactly 50 years ago, first described a power plant involving the coupling of a helium gas turbine with a uranium heater.

Analysis on the Performance Characteristics of SOFC/GT Hybrid Systems Based on a Commercially Available MW-Class Gas Turbine

2005 ◽  
Author(s):  
Tae Won Song ◽  
Jeong L. Sohn ◽  
Tong Seop Kim ◽  
Sung Tack Ro
Keyword(s):  
Gas Turbine ◽  
Hybrid System ◽  
Guide Vane ◽  
Control Strategies ◽  
Operating Conditions ◽  
Performance Characteristics ◽  
Inlet Guide Vane ◽  
Part Load ◽  
Optimal Power ◽  
Selection Of

To investigate the possible applications of the SOFC/MGT hybrid system to large electric power generations, a study for the kW-class hybrid power system conducted in our group is extended to the MW-class hybrid system in this study. Because of the matured technology of the gas turbine and commercial availability in the market, it is reasonable to construct a hybrid system with the selection of a gas turbine as an off-the-shelf item. For this purpose, the performance analysis is conducted to find out the optimal power size of the hybrid system based on a commercially available gas turbine. The optimal power size has to be selected by considering specifications of a selected gas turbine which limit the performance of the hybrid system. Also, the cell temperature of the SOFC is another limiting parameter to be considered in the selection of the optimal power size. Because of different system configuration of the hybrid system, the control strategies for the part-load operation of the MW-class hybrid system are quite different from the kW-class case. Also, it is necessary to consider that the control of supplied air to the MW-class gas turbine is typically done by the variable inlet guide vane located in front of the compressor inlet, instead of the control of variable rotational speed of the kW-class micro gas turbine. Performance characteristics at part-load operating conditions with different kinds of control strategies of supplied fuel and air to the hybrid system are investigated in this study.

Solar Hybrid Combined Cycle Performance Prediction: Influence of GT Model and Spool Arrangement

2012 ◽  
Author(s):  
G. Barigozzi ◽  
G. Bonetti ◽  
G. Franchini ◽  
A. Perdichizzi ◽  
S. Ravelli
Keyword(s):  
Gas Turbine ◽  
Performance Prediction ◽  
Gas Turbines ◽  
Control Strategies ◽  
Rankine Cycle ◽  
Simulation Method ◽  
Power Input ◽  
Combined Cycle ◽  
Cycle Performance ◽  
Solar Field

A modeling procedure was developed to simulate design and off-design operation of Hybrid Solar Gas Turbines in a combined cycle (CC) configuration. The system includes an heliostat field, a receiver and a commercial gas turbine interfaced with a conventional steam Rankine cycle. Solar power input is integrated in the GT combustor by natural gas. Advanced commercial software tools were combined together to get design and off-design performance prediction: TRNSYS® was used to model the solar field and the receiver while the gas turbine and steam cycle simulations were performed by means of Thermoflex®. Three GT models were considered, in the 35–45 MWe range: a single shaft engine (Siemens SGT800) and two two-shaft engines (the heavy-duty GT Siemens SGT750 and the aero derivative GE LM6000 PF). This in order to assess the influence of different GT spool arrangements and control strategies on GT solarization. The simulation method provided an accurate modeling of the daily solar hybrid CC behavior to be compared against the standard CC. The effects of solarization were estimated in terms of electric power and efficiency reduction, fossil fuel saving and solar energy to electricity conversion efficiency.

Gas Turbine Exhaust Expansion Joints, Diverter and Damper Designs for the New Generation of Higher Temperature, High Efficiency Gas Turbines

1989 ◽  
Author(s):  
Lothar Bachmann ◽  
W. Fred Koch
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Combined Cycle ◽  
Operating Conditions ◽  
High Mass ◽  
Expansion Joints ◽  
Gas Turbine Exhaust ◽  
New Generation ◽  
Turbine Exhaust

The purpose of this paper is to update the industry on the evolutionary steps that have been taken to address higher requirements imposed on the new generation combined cycle gas turbine exhaust ducting expansion joints, diverter and damper systems. Since the more challenging applications are in the larger systems, we shall concentrate on sizes from nine (9) square meters up to forty (40) square meters in ducting cross sections. (Reference: General Electric Frame 5 through Frame 9 sizes.) Severe problems encountered in gas turbine applications for the subject equipment are mostly traceable to stress buckling caused by differential expansion of components, improper insulation, unsuitable or incompatible mechanical design of features, components or materials, or poor workmanship. Conventional power plant expansion joints or dampers are designed for entirely different operating conditions and should not be applied in gas turbine applications. The sharp transients during gas turbine start-up as well as the very high temperature and high mass-flow operation conditions require specific designs for gas turbine application.

Fuzzy Logic Control Strategy for an Extended-Range Electric Vehicle

2012 ◽  
Vol 220-223 ◽  
pp. 968-972 ◽  
Author(s):  
Ji Gao Niu ◽  
Su Zhou
Keyword(s):  
Fuzzy Logic ◽  
Electric Vehicle ◽  
Control Strategy ◽  
Fuzzy Logic Control ◽  
High Efficiency ◽  
Control Strategies ◽  
Vehicle Performance ◽  
Logic Control ◽  
Extended Range ◽  
Avl Cruise

This paper presents a Fuzzy Logic Control Strategy (FLCS) for an Extended-range Electric Vehicle (E-REV) with series structure. The control strategy design objective of the E-REV is fuel economy. Based on the State of Charge (SOC) of the battery and the desired power for driving, the power required by the vehicle is split between the engine/generator set and the battery by the FLCS. The engine can be operated consistently in a very high efficiency area and the SOC of the battery can be maintained at a reasonable level. Some standard driving cycles and two control strategies of Power Follower Control Strategy (PFCS) and FLCS were simulated with AVL-Cruise and Matlab/Simulink to analyze the vehicle performance. Some simulation results are compared and discussed: the FLCS indicates better performance in terms of fuel consumption.

Dynamic Analysis of Concentrated Solar Hybridised Gas Turbine

2014 ◽  
Author(s):  
Alberto Traverso ◽  
Stefano Barberis ◽  
Davide Lima ◽  
Aristide F. Massardo
Keyword(s):  
Gas Turbine ◽  
Control Strategy ◽  
High Efficiency ◽  
Combined Cycle ◽  
Hot Air ◽  
Air Valve ◽  
Power Capability ◽  
The University ◽  
Solar Field ◽  
Cycle Efficiency

In this work the dynamic behaviour and the control strategy of a 12MWe size gas turbine hybridised with concentrated solar heat source has been investigated. Hybridised gas turbine cycles are attractive because of their high efficiency, potentially equal to combined cycle efficiency, and because of their dispatchable power capability. An existing gas turbine model has been modified into a hybrid layout to incorporate high temperature heat from a concentrated solar field, through a high pressure air-cooled receiver. The system does not involve any hot air valve and includes a ceramic thermal storage. The plant dynamic model was developed using the original TRANSEO simulation tool developed at the University of Genoa. Initially, plant steady-state performance is analysed, identifying potential issues. Then, the different dynamic operations (storage charging, discharging and bypass) are simulated, showing the feasibility of the control strategy proposed. Eventually, design recommendations are drawn to improve the flexibility and the time response of such kind of plants.

Numerical Simulation for the Preliminary Design of Fuel Flexible Stationary Gas Turbine Combustors Using Conventional and Alternative Fuels

2012 ◽  
Author(s):  
Washington Orlando Irrazabal Bohorquez ◽  
João Roberto Barbosa ◽  
Rob Johan Maria Bastiaans ◽  
Philip de Goey
Keyword(s):  
Numerical Simulation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Alternative Fuels ◽  
High Efficiency ◽  
Numerical Study ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Gas Turbine Combustor ◽  
Primary Zone

Currently, high efficiency and low emissions are most important requisites for the design of modern gas turbines due to the strong environmental restrictions around the world. In the past years, alternative fuels have been considered for application in industrial gas turbines. Therefore, combustor performance, pollutant emissions and the ability to burn several fuels became of much concern and high priority has been given to the combustor design. This paper describes a methodology focused on the design of stationary gas turbines combustion chambers with the ability to efficiently burn conventional and alternative fuels. A simplified methodology is used for the calculations of the equilibrium temperature and chemical species in the primary zone of a gas turbine combustor. Direct fuel injection and diffusion flames, together with numerical methods like Newton-Raphson, LU Factorization and Lagrange Polynomials, are used for the calculations. Diesel, ethanol and methanol fuels were chosen for the numerical study. A computer code sequentially calculates the main geometry of the combustor. From the numerical simulation it is concluded that the basic gas turbine combustor geometry, for some operating conditions and burning diesel, ethanol or methanol, are of similar sizes, because the development of aerodynamic characteristics predominate over the thermochemical properties. It is worth to note that the type of fuel has a marked effect on the stability and combustion advancement in the combustor. This can be seen when the primary zone is analyzed under a steady-state operating condition. At full power, the pressure is 1.8 MPa and the temperature 1,000 K at the combustor inlet. Then, the equivalence ratios in the primary zone are 1.3933 (diesel), 1.4352 (ethanol) and 1.3977 (methanol) and the equilibrium temperatures for the same operating conditions are 2,809 K (diesel), 2,754 K (ethanol) and 2,702 K (methanol). This means that the combustor can reach similar flame stability conditions, whereas the combustion efficiency will require richer fuel/air mixtures of ethanol or methanol are burnt instead of diesel. Another important result from the numerical study is that the concentration of the main pollutants (CO, CO2, NO, NO2) is reduced when ethanol or methanol are burnt, in place of diesel.

Improved Gas Turbine Efficiency Through Alternative Regenerator Configuration

2002 ◽  
Author(s):  
Paul A. Dellenback
Keyword(s):  
Gas Turbine ◽  
Operating Conditions ◽  
Cycle Performance ◽  
Inlet Temperature ◽  
Optimum Pressure ◽  
Model Calculations ◽  
Turbine Engine ◽  
Combustion Gases ◽  
Wide Range ◽  
Temperature Combustion

An alternative configuration for a regenerative gas turbine engine cycle is presented that yields higher cycle efficiencies than either simple or conventional regenerative cycles operating under the same conditions. The essence of the scheme is to preheat compressor discharge air with high temperature combustion gases before the latter are fully expanded across the turbine. The efficiency is improved because air enters the combustor at a higher temperature, and hence heat addition in the combustor occurs at a higher average temperature. The heat exchanger operating conditions are more demanding than for a conventional regeneration configuration, but well within the capability of modern heat exchangers. Models of cycle performance exhibit several percentage points of improvement relative to either simple cycles or conventional regeneration schemes. The peak efficiencies of the alternative regeneration configuration occur at optimum pressure ratios that are significantly lower than those required for the simple cycle. For example, at a turbine inlet temperature of 1300°C (2370°F), the alternative regeneration scheme results in cycle efficiencies of 50% for overall pressure ratios of 22, whereas simple cycles operating at the same temperature would yield efficiencies of only 43.8% at optimum pressure ratios of 50, which are not feasible with current compressor designs. Model calculations for a wide range of parameters are presented, as are comparisons with simple and conventional regeneration cycles.

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