Modelling and Performance Analysis of Stationary Gas Turbines Operating Under Rotational Speed Transients

2021 ◽  
Author(s):  
André L. S. Andade ◽  
Osvaldo J. Venturini ◽  
Vladimir R. M. Cobas ◽  
Vinicius Zimmerman Silva
Keyword(s):  
Gas Turbines ◽  
Engine Performance ◽  
Heat Rate ◽  
Gas Generator ◽  
Transient Regimes ◽  
Power Turbine ◽  
Nominal Capacity ◽  
Prime Movers ◽  
And Performance ◽  
Operational Envelope

Abstract In order to increase the flexibility and performance of gas turbines, generally their manufacturers and research centers involved in their development are constantly seeking the expansion of their operational envelope as well as their efficiency, making the engine more dynamic, less polluting and able to respond promptly to variations in load demands. An important aspect that should be considered when analyzing these prime movers is the assessment of its behavior under transients due to load changes, which can be accomplished through the development of a detailed, accurate and effective computational model. Considering this scenario, the present work aims to develop a model for the simulation and analysis of the dynamic behavior of stationary gas turbines. The engine considered in this analysis has a nominal capacity of 30.7 MW (ISO conditions) and is composed by a two-spool gas generator and a free power turbine. The model was developed using T-MATS, an integrated Simulink/Matlab toolbox, develop by NASA. The gas turbine was evaluated under both permanent and transient regimes and each one of its component was analyzed individually. The assessment made it possible to determine the engine performance parameters such as efficiency, heat rate and specific fuel consumption and its operational limits (surge limits, stall, turbine inlet temperatures, etc.) under different load conditions and regimes. The results obtained were compared with available field data, and the relative deviations for the considered parameters were all lower than 1%.

Aeroderivative Mechanical Drive Gas Turbines: The Design of Intermediate Pressure Turbines

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Alberto Scotti Del Greco ◽  
Vittorio Michelassi ◽  
Stefano Francini ◽  
Daniele Di Benedetto ◽  
Mahendran Manoharan
Keyword(s):  
Gas Turbines ◽  
Engine Performance ◽  
Aircraft Engine ◽  
Secondary Flows ◽  
Power Turbine ◽  
Through Flow ◽  
Booster Compressor ◽  
Flow Curvature ◽  
Emission Limits ◽  
And Performance

Gas turbines engine designers are leaning toward aircraft engine architectures due to their footprint, weight, and performance advantages. Such engines need some modifications to both the combustion system, to comply with emission limits, and turbine rotational speed. Aeroderivative engines maintain the same legacy aircraft engine architecture and replace the fan and booster with a higher speed compressor booster driven by a single-stage intermediate turbine. A multistage free power turbine (FPT) sits on a separate shaft to drive compressors for liquefied natural gas (LNG) applications or generators. The intermediate-power turbine (IPT) design is important for the engine performance as it drives the booster compressor and sets the inlet boundary conditions to the downstream power turbine. This paper describes the experience of Baker Hughes, a GE company (BHGE) in the design of the intermediate turbine that sits in between a GE legacy aircraft engine core exhaust and the downstream power turbine. This paper focuses on the flow path of the turbine center frame (TCF)/intermediate turbine and the associated design, as well as on the 3D steady and unsteady computational fluid dynamics (CFD)-assisted design of the IPT stage to control secondary flows in presence of through flow curvature induced by the upstream TCF.

Aero Derivative Mechanical Drive Gas Turbines: The Design of Intermediate Pressure Turbines

2018 ◽  
Author(s):  
Alberto Scotti Del Greco ◽  
Vittorio Michelassi ◽  
Stefano Francini ◽  
Daniele Di Benedetto ◽  
Mahendran Manoharan
Keyword(s):  
Gas Turbines ◽  
Engine Performance ◽  
Aircraft Engine ◽  
Secondary Flows ◽  
Power Turbine ◽  
Through Flow ◽  
Booster Compressor ◽  
Flow Curvature ◽  
Emission Limits ◽  
And Performance

Gas turbines engine designers are leaning towards aircraft engine architectures due to their footprint, weight, and performance advantages. Such engines need some modifications to both the combustion system, to comply with emission limits, and turbine rotational speed. Aero derivative engines maintain the same legacy aircraft engine architecture, and replace the fan and booster with higher speed compressor booster driven by a single stage intermediate turbine. A multistage free power turbine (FPT) sits on a separate shaft to drive compressors for Liquefied Natural Gas (LNG) applications or generators. The intermediate power turbine (IPT) design is important for the engine performance as it drives the booster compressor and sets the inlet boundary conditions to the downstream power turbine. This paper describes the experience of Baker Hughes, a GE company (BHGE) in the design of the intermediate turbine that sits in between a GE legacy aircraft engine core exhaust and the downstream power turbine. This paper focuses on the flow path of the TCF/intermediate turbine and the associated design, as well as on the 3D steady and unsteady CFD assisted design of the IPT stage to control secondary flows in presence of through flow curvature induced by the upstream TCF.

Advanced Control System Considerations for Small Shaft-Type Aircraft Gas Turbines

1970 ◽  
Author(s):  
D. A. Prue ◽  
T. L. Soule
Keyword(s):  
Control System ◽  
Gas Turbines ◽  
Evaluation Criteria ◽  
Open Loop ◽  
Engine Control ◽  
Gas Generator ◽  
Engine Control System ◽  
Power Turbine ◽  
Advanced Control ◽  
Temperature Load

The next generation of free-turbine engines in the 2 to 5-lb/sec airflow class will undergo vast improvements in performance and efficiency. The improvements will be achieved concurrent with overall reductions in size and weight. Effort is required at optimization and miniaturization of the engine control system to keep pace with these improvements. This paper describes a conceptual design of an advanced engine control system for this class of engine. It provides gas generator and power turbine control with torque, temperature, load sharing and overspeed limiting functions. The control system was concepted to accommodate, with minimum hardware changes, such variants as regenerative cycle and/or variable power turbine geometry. In addition, considerations for closed and open loop modes of control and fluidic, electronic and hydromechanical technologies were studied to best meet a defined specification and a weighted set of evaluation criteria.

Regenerative Gas Turbines With Divided Expansion

2004 ◽  
Author(s):  
Brian Elmegaard ◽  
Bjo̸rn Qvale
Keyword(s):  
Mathematical Model ◽  
Gas Turbines ◽  
High Efficiency ◽  
Limited Range ◽  
Simulation Program ◽  
Operating Parameters ◽  
Gas Generator ◽  
Extensive Simulation ◽  
Power Turbine ◽  
The Mathematical Model

Recuperated gas turbines are currently drawing an increased attention due to the recent commercialization of micro gas turbines with recuperation. This system may reach a high efficiency even for the small units of less than 100kW. In order to improve the economics of the plants, ways to improve their efficiency are always of interest. Recently, two independent studies have proposed recuperated gas turbines to be configured with the turbine expansion divided, in order to obtain higher efficiency. The idea is to operate the system with a gas generator and a power turbine, and use the gas from the gas generator part for recuperation ahead of the expansion in the power turbine. The present study is more complete than the predecessors in that the ranges of the parameters have been extended and the mathematical model is more realistic using an extensive simulation program. It is confirmed that the proposed divided expansion can be advantageous under certain circumstances. But, in order for todays micro gas turbines to be competitive, the thermodynamic efficiencies will have to be rather high. This requires that all component efficiencies including the recuperator effectiveness will have to be high. The advantages of the divided expansion manifest themselves over a rather limited range of the operating parameters, that lies outside the range required to make modern micro turbines economically competitive.

Capacity Matching of Aeroderivative Gas Generator With Free Power Turbine: Challenges, Uncertainties, and Opportunities

2019 ◽  
Author(s):  
Deepak Thirumurthy ◽  
Jose Carlos Casado Coca ◽  
Kanishka Suraweera
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Systems Approach ◽  
Gas Generator ◽  
Performance Guarantees ◽  
Design Variables ◽  
Performance Trends ◽  
Power Turbine ◽  
Parameter Matching ◽  
Turbine Capacity

Abstract For gas turbines with free power turbines, the capacity or flow parameter matching is of prime importance. Accurately matched capacity enables the gas turbine to run at its optimum conditions. This ensures maximum component efficiencies, and optimum shaft speeds within mechanical limits. This paper presents the challenges, uncertainties, and opportunities associated with an accurate matching of a generic two-shaft aeroderivative HP-LP gas generator with the free power turbine. Additionally, generic performance trends, uncertainty quantification, and results from the verification program are also discussed. These results are necessary to ensure that the final free power turbine capacity is within the allowable range and hence the product meets the performance guarantees. The sensitivity of free power turbine capacity to various design variables such as the vane throat area, vane trailing edge size, and manufacturing tolerance is presented. In addition, issues that may arise due to not meeting the target capacity are also discussed. To conclude, in addition to design, analysis, and statistical studies, a system-of-systems approach is mandatory to meet the allowed variation in the free power turbine capacity and hence the desired gas turbine performance.

An Application Oriented Gas Turbine Laboratory Experience

2004 ◽  
Author(s):  
Kenneth W. Van Treuren
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Engine Performance ◽  
Data Set ◽  
Actual Performance ◽  
Turbine Engine ◽  
Practical Applications ◽  
Baylor University ◽  
And Performance ◽  
Technology Level

The gas turbine industry is experiencing growth in many sectors. An important part of teaching a gas turbine course is exposing students to the practical applications of the gas turbine. This laboratory proposes an opportunity for students to view an operating gas turbine engine in an aircraft propulsion application and to model the engine performance. A Pratt and Whitney PT6A-20 turboprop was run at a local airfield and engine parameters typical of cockpit instrumentation were taken. The students, in teams of two, then modeled the system using the software PARA and PERF in an attempt to match the manufacturer’s specifications. This laboratory required students to research the parameters necessary to model this engine that were not part of the data set provided by the manufacturer. The research and modeling encompassed areas such as technology level, efficiencies, fuel consumption, and performance. The end result was a two-page report containing the students’ calculations comparing the actual performance of the engine with the manufacturer’s specifications. Supporting graphs and figures were included as appendices. The same type laboratory could be adapted for co-generation gas turbines. Over 121 colleges and universities have co-generation facilities on campus and that presents a unique opportunity for the students to observe the operation of a land-based gas turbine used for power generation. A 5 MW TB5000 manufactured by Ruston (Alstom) Gas Engines is available on the Baylor University campus and is highlighted as an example. Potential problems encountered with using the Baylor University gas turbine are discussed which include lack of appropriate engine instrumentation.

scholarly journals A New Turbine for Natural Gas Pipelines

1999 ◽  
Vol 121 (05) ◽  
pp. 72-74
Author(s):  
Jay M. Wilson ◽  
Henry Baumgartner
Keyword(s):  
High Efficiency ◽  
Fuel Efficiency ◽  
Engine Performance ◽  
Aircraft Engine ◽  
Gas Generator ◽  
Natural Gas Pipelines ◽  
Modular Concept ◽  
Power Turbine ◽  
Temperature Capability ◽  
Turbine Design

The new Cooper-Bessemer power turbine is a high-efficiency, center frame-mounted, three-stage unit that can be driven by either the existing RB211-24 gas generator or the new improved version. The upgraded gas generator combined with the new power turbine offers an increase in nominal output from 28.4 MW (38,000 hp) to 31.8 MW (42,600 hp). The new coupled turbine, now being tested, is called the Coberra 6761. Besides improving core engine performance, the program's objectives included improved fuel efficiency and reliability, and easier site serviceability; extension of the modular concept from the gas generator into the power turbine with improvements in sealing, materials, and temperature capability as well as interchangeability of both upgraded turbines with existing hardware. The Rolls-Royce industrial RB211 turbine, derived from an aircraft engine, is the basis for the gas generator end of Cooper Energy Services' Coberra coupled turbines. The power turbine design capacity has a significant effect on the power at a given speed. The flow capacity was optimized to achieve the best thermal efficiency and lower IP speeds to optimize IP compressor efficiency and permit future throttle push.

scholarly journals Results of the GT Prime Program Improvements to General Electric MS7001B Gas Turbines at the Houston Light and Power T.H. Wharton Site

1998 ◽  
Author(s):  
Jerome Svatek ◽  
Michael Elliott ◽  
Paul Crabtree ◽  
Gerald E. Jurczynski ◽  
John R. (Bob) Johnston
Keyword(s):  
Gas Turbines ◽  
Heat Rate ◽  
Combined Cycle ◽  
High Rate ◽  
Operating Costs ◽  
General Electric ◽  
Hot Gas ◽  
Program Schedule ◽  
Design Changes ◽  
And Performance

At the time of the start of the GT PRIME upgrade project, the eight General Electric MS7001 gas turbines in combined cycle service at the Wharton Station of Houston lighting and Power each had 85,000 hours of operation with 2000 starts. The units were ready for their second major overhaul. A number of hot gas path components required replacement at that time. Rather than replacing components one by one, the user devised a Program for Reliability, Improved Maintenance, and Efficiency (GT PRIME). We will discuss turbine condition, design changes, reduced emissions, and increased output in the paper. Actual user experience on maintenance and operating costs resulted in some special requirements to be satisfied in addition to the expected parts replacement. General Electric had developed many improved parts for newer units, all of which could be easily applied to older machines. The use of these newer production MS7001EA parts increase component life, parts availability, inspection intervals, system reliability and performance. These will be described in the paper. These 1972 vintage turbines achieved a 50PPM NOx level by injecting water at a high rate of flow which resulted in the need for more frequent combustion inspection intervals. The development of a dry low NOx system for the unit allowed the combustion inspection interval to double while reducing NOx to 25PPM. The improvement in component efficiencies in the gas path resulted in increased output and improved the heat rate. These changes had a significant impact on customer operating costs which resulted in a very attractive payback period. We will discuss expected versus actual output, heat rate and emissions results for all eight units. The upgrade of the first unit started in 1992 and the last unit was completed in 1996. A detailed listing of uprate program schedule by unit is listed in Figure #1.

scholarly journals Alternate Ways of Using Bottoming Cycle Power in Pipeline Gas Compressor Stations

1979 ◽  
Author(s):  
R. J. Rossbach
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Heat Rate ◽  
Department Of Energy ◽  
General Electric ◽  
General Electric Company ◽  
Target Value ◽  
Electric Company ◽  
Cycle Systems ◽  
Prime Movers

The General Electric Company is carrying out a design study and evaluation of bottoming cycles for gas pipeline compressor prime movers. Three sites were chosen for the study of demonstration organic bottoming cycles of about 5000 hp applied to three aircraft derivative gas turbines of approximately the same size. The purpose of the study is to design and evaluate all important aspects of installing organic bottoming cycle systems on a selected group of gas turbine prime movers driving gas compressors. As a result of the study, it was found that pipeline bottoming cycles applied to gas turbine prime movers could reduce the heat rate 35 percent more than the Department of Energy target value of 20 percent. Installation designs for three sites are described.

Analysis of Operational Effects on Cooled H-Class Gas Turbines

2019 ◽  
Author(s):  
Selcuk Can Uysal ◽  
James B. Black
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Power Output ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Cooling System ◽  
Engine Performance ◽  
Heat Rate ◽  
Operating Conditions ◽  
Performance Parameters

Abstract During the operation of an industrial gas turbine, the engine deviates from its new condition performance because of several effects including dirt build-up, compressor fouling, material erosion, oxidation, corrosion, turbine blade burning or warping, thermal barrier coating (TBC) degradation, and turbine blade cooling channel clogging. Once these problems cause a significant impact on engine performance, maintenance actions are taken by the operators to restore the engine to new performance levels. It is important to quantify the impacts of these operational effects on the key engine performance parameters such as power output, heat rate and thermal efficiency for industrial gas turbines during the design phase. This information can be used to determine an engine maintenance schedule, which is directly related to maintenance costs during the anticipated operational time. A cooled gas turbine performance analysis model is used in this study to determine the impacts of the TBC degradation and compressor fouling on the engine performance by using three different H-Class gas turbine scenarios. The analytical tool that is used in this analysis is the Cooled Gas Turbine Model (CGTM) that was previously developed in MATLAB Simulink®. The CGTM evaluates the engine performance using operating conditions, polytropic efficiencies, material properties and cooling system information. To investigate the negative impacts on engine performance due to structural changes in TBC material, compressor fouling, and their combined effect, CGTM is used in this study for three different H-Class engine scenarios that have various compressor pressure ratios, turbine inlet temperatures, and power and thermal efficiency outputs; each determined to represent different classes of recent H-Class gas turbines. Experimental data on the changes in TBC performance are used as an input to the CGTM as a change in the TBC Biot number to observe the impacts on engine performance. The effect of compressor fouling is studied by changing the compressor discharge pressures and polytropic compressor efficiencies within the expected reduction ranges. The individual and combined effects of compressor fouling and TBC degradation are presented for the shaft power output, thermal efficiency and heat rate performance parameters. Possible improvements for the designers to reduce these impacts, and comparison of the reductions in engine performance parameters of the studied H-Class engine scenarios are also provided.

Sign in / Sign up

Export Citation Format

Share Document