Off-Design Performance of Various Gas-Turbine Cycle and Shaft Configurations

1999 ◽  
Vol 121 (4) ◽  
pp. 649-655 ◽  
Author(s):  
T. Korakianitis ◽  
K. Svensson
Keyword(s):  
Computer Program ◽  
Gas Turbine ◽  
Operational Flexibility ◽  
Design Point ◽  
Design Performance ◽  
Advantages And Disadvantages ◽  
Power Turbine ◽  
Turbine Shaft ◽  
Gas Turbine Cycle

The design-point performance of various gas turbine cycles such as simple, regenerative, and intercooled-regenerative, is well understood. It is also understood that more elaborate shaft arrangements such as one, two, or three concentric or nonconcentric shafts, and a separate power turbine shaft, provide better starting and operational flexibility, and wider plateaus of high off-design performance. However, the types of different off-design performance one can obtain with these different shaft arrangements has not been previously reported. In this paper we use a computer program to investigate the design-point and off-design-point performance of engines with the following: one single shaft joining the compressor, turbine and load; one shaft joining compressor and turbine, and one shaft for the power turbine; two shafts for compressor and turbine, and one shaft for the power turbine; and three shafts joining the compressor and turbine, and one shaft for the power turbine. This is done by specifying typical compressor and turbine maps, and computing various aspects of off-design performance. The advantages and disadvantages of the various arrangements are investigated and discussed.

Off-Design Performance of Various Gas-Turbine Cycle and Shaft Configurations

1998 ◽  
Author(s):  
T. Korakianitis ◽  
K. Svensson
Keyword(s):  
Computer Program ◽  
Gas Turbine ◽  
Operational Flexibility ◽  
Design Point ◽  
Design Performance ◽  
Advantages And Disadvantages ◽  
Power Turbine ◽  
Turbine Shaft ◽  
Gas Turbine Cycle

The design-point performance of various gas turbine cycles such as simple, regenerative, and intercooled-regenerative, is well understood. It is also understood that more-elaborate shaft arrangements such as one, two or three concentric or non-concentric shafts, and a separate power turbine shaft, provide better starting and operational flexibility, and wider plateaus of high off-design performance. However, the types of different off-design performance one can obtain with these different shaft arrangements has not been previously reported. In this paper we use a computer program to investigate the design-point and off-design-point performance of engines with: one single shaft joining the compressor, turbine and load; one shaft joining compressor and turbine, and one shaft for the power turbine; two shafts for compressor and turbine, and one shaft for the power turbine; and three shafts joining the compressor and turbine, and one shaft for the power turbine. This is done by specifying typical compressor and turbine maps, and computing various aspects of off-design performance. The advantages and disadvantages of the various arrangements ore investigated and discussed.

scholarly journals An Optimizing Design Point Program for Selection of a Gas Turbine Cycle

1977 ◽  
Author(s):  
G. K. Conkol ◽  
T. Singh
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Design Parameters ◽  
Turbine Engines ◽  
Original Design ◽  
Ground Vehicle ◽  
Design Point ◽  
Optimizing Design ◽  
Volume Characteristics ◽  
Gas Turbine Cycle

As vehicles evolve through the concept phase, a wide variety of engines are usually considered. For long-life vehicles such as heavy armored tracked vehicles, gas turbines have been favored because of their weight and volume characteristics at high hp levels (1500 to 2000 hp). Many existing gas turbine engines, however, are undesirable for vehicular use because their original design philosophy was aircraft oriented. In a ground vehicle, mass flow and expense are only two areas in which these engines differ greatly. Because the designer generally is not given the freedom to design an engine from scratch, he must evaluate modifications of the basic Brayton cycle. In this study, various cycles are evaluated by using a design point program in order to optimize design parameters and to recommend a cycle for heavy vehicular use.

scholarly journals Gas Turbine Cycle Design Methodology: A Comparison of Parameter Variation With Numerical Optimization

1998 ◽  
Author(s):  
Joachim Kurzke
Keyword(s):  
Gas Turbine ◽  
Numerical Optimization ◽  
Graphical Representation ◽  
Thermodynamic Cycle ◽  
Parameter Variation ◽  
Parameter Study ◽  
Design Point ◽  
Optimization Task ◽  
Gas Turbine Cycle ◽  
Simulation Task

In gas turbine performance simulations often the question arises: What is the best thermodynamic cycle design point? This is an optimization task which can be attacked in two ways: One can do a series of parameter variations and pick from the resulting graphs the best solution or one can employ numerical optimization algorithms that produce a single cycle which fulfills all constraints. The conventional parameter study builds strongly on the engineering judgement and gives useful information over a range of parameter selections. However, when values for more than a few variables have to be determined while several constraints are existing, then numerical optimization routines can help to find the mathematical optimum faster and more accurately. Sometimes even an outstanding solution is found which was overlooked while doing a preliminary parameter study. For any simulation task a sophisticated graphical user interface is of great benefit. This is especially true for automated numerical optimizations. It is quite helpful to see on the screen of a PC how the variables are changing and which constraints are limiting the design. A quick and clear graphical representation of trade studies is also of great advantage. The paper describes how numerical optimization and parameter studies are implemented in a Windows-based PC program. As an example, the cycle selection of a derivative turbofan engine with a given core shows the merits of numerical optimization. The parameter variation is best suited for presenting the sensitivity of the result in the neighborhood of the optimum cycle design point.

Gas Turbine Cycle Design Methodology: A Comparison of Parameter Variation With Numerical Optimization

1999 ◽  
Vol 121 (1) ◽  
pp. 6-11 ◽  
Author(s):  
J. Kurzke
Keyword(s):  
Gas Turbine ◽  
Numerical Optimization ◽  
Graphical Representation ◽  
Thermodynamic Cycle ◽  
Parameter Variation ◽  
Parameter Study ◽  
Design Point ◽  
Optimization Task ◽  
Gas Turbine Cycle ◽  
Simulation Task

In gas turbine performance simulations often the following question arises: what is the best thermodynamic cycle design point? This is an optimization task which can be attacked in two ways. One can do a series of parameter variations and pick from the resulting graphs the best solution or one can employ numerical optimization algorithms that produce a single cycle that fulfills all constraints. The conventional parameter study builds strongly on the engineering judgement and gives useful information over a range of parameter selections. However, when values for more than a few variables have to be determined while several constraints are existing, then numerical optimization routines can help to find the mathematical optimum faster and more accurately. Sometimes even an outstanding solution is found which was overlooked while doing a preliminary parameter study. For any simulation task a sophisticated graphical user interface is of great benefit. This is especially true for automated numerical optimizations. It is quite helpful to see on the screen of a PC how the variables are changing and which constraints are limiting the design. A quick and clear graphical representation of trade studies is also of great advantage. The paper describes how numerical optimization and parameter studies are implemented in a Windows-based PC program. As an example, the cycle selection of a derivative turbofan engine with a given core shows the merits of numerical optimization. The parameter variation is best suited for presenting the sensitivity of the result in the neighborhood of the optimum cycle design point.

Gas Turbine Off-Design Performance Adaptation Using a Genetic Algorithm

2006 ◽  
Author(s):  
E. Lo Gatto ◽  
Y. G. Li ◽  
P. Pilidis
Keyword(s):  
Genetic Algorithm ◽  
Gas Turbine ◽  
Performance Prediction ◽  
Engine Performance ◽  
Design Data ◽  
Adaptive Approach ◽  
Design Point ◽  
Design Performance ◽  
Engine Design ◽  
Performance Adaptation

Gas turbine gas path diagnostics is heavily dependent on performance simulation models accurate enough around a chosen diagnostic operating point, such as design operating point. With current technology, gas turbine engine performance can be predicted easily with thermodynamic models and computer codes together with basic engine design data and empirical component information. However the accuracy of the prediction is highly dependent on the quality of those engine design data and empirical component information such as component characteristic maps but such expensive information is normally exclusive property of engine manufacturers and only partially disclosed to engine users. Alternatively, estimated design data and assumed component information are used in the performance prediction. Yet, such assumed component information may not be the same as those of real engines and therefore poor off-design performance prediction may be produced. This paper presents an adaptive method to improve the accuracy of off-design performance prediction of engine models near engine design point or other points where detailed knowledge is available. A novel definition of off-design scaling factors for the modification of compressor maps is developed. A Genetic Algorithm is used to search the best set of scaling factors in order to adapt the predicted off-design engine performance to observed engine off-design performance. As the outcome of the procedure, new compressor maps are produced and more accurate prediction of off-design performance is provided. The proposed off-design performance adaptation procedure is applied to a model civil aero engine to test the effectiveness of the adaptive approach. The results show that the developed adaptive approach, if properly applied, has great potential to improve the accuracy of engine off-design performance prediction in the vicinity of engine design point although it does not guarantee the prediction accuracy in the whole range of off-design conditions. Therefore, such adaptive approach provides an alternative method in producing good engine performance models for gas turbine gas path diagnostic analysis.

scholarly journals TopCycle: A Novel High Performance and Fuel Flexible Gas Turbine Cycle

2021 ◽  
Vol 13 (2) ◽  
pp. 651
Author(s):  
Simeon Dybe ◽  
Michael Bartlett ◽  
Jens Pålsson ◽  
Panagiotis Stathopoulos
Keyword(s):  
Gas Turbine ◽  
High Performance ◽  
Combined Cycle ◽  
Cycle Performance ◽  
Inlet Temperature ◽  
Operational Flexibility ◽  
Working Pressure ◽  
Lower Heating Value ◽  
Higher Power ◽  
Gas Turbine Cycle

High pressure humidified cycles can combine high operational flexibility and high thermal efficiency. The current work introduces such a cycle, namely TopCycle, which provides the necessary combustion infrastructure to operate on a wide fuel variety in a steam-rich atmosphere. The cycle configuration is presented in detail, and its operation is exemplified on the basis of simulation results. Operation at design condition results in electric efficiencies higher than 50% (lower heating value (LHV)) and power densities higher than 2100 kW/kgair (referred to intake air flow). A sensitivity analysis identifies the cycle performance as a function of representative parameters, which provide the basis for future operation and design improvements. As for any gas turbine cycle, TopCycle’s electric efficiency can be effectively improved by increasing the turbine inlet temperature, optimizing the economizer heat recovery, as well as elevating the working pressure. Finally, TopCycle’s performance is compared to a state-of-the-art combined cycle (CC) at equivalent operation parameters. The TopCycle operates at an elevated electric efficiency and considerably higher power density, which can be transferred into smaller plant footprint and dimensions and thus lower investment costs at equal power output in comparison to a CC.

The Map Fitting Tool Methodology: Gas Turbine Compressor Off-Design Performance Modeling

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Vishal Sethi ◽  
Georgios Doulgeris ◽  
Pericles Pilidis ◽  
Alex Nind ◽  
Marc Doussinault ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Object Oriented ◽  
Parametric Representation ◽  
Simulation Software ◽  
Performance Simulation ◽  
Design Performance ◽  
Advantages And Disadvantages ◽  
Compressor Performance ◽  
Gas Turbine Compressor ◽  
Component Models

This paper describes the structure and the implementation of an extended parametric representation of compressor characteristics for a modern object oriented gas turbine performance simulation software (PROOSIS). The proposed methodology is the map fitting tool (MFT) methodology. The proposed MFT methodology for modeling the off design performance of gas turbine turbomachinery components (fans, compressors, and turbines) is based on a concept conceived and developed collaboratively by General Electric (GE) and NASA. This paper provides a short description of both BETA and MFT compressor maps, as well as the development of compressor component models in PROOSIS capable of using both types of maps for off design compressor performance prediction. The work presented in this paper is the outcome of a collaborative effort between Snecma Moteurs and Cranfield University as part of the European Cycle Program of the EU FP6 collaborative project—VIVACE. A detailed description of the MFT map methodology is provided with a “step-by-step” calculation procedure. Synergies between compressor MFT and compressor BETA calculations are also highlighted and a description of how these two components have been integrated into an object oriented simulation software with component hierarchy is also presented. Advanced parametric representations of fan and turbine characteristics have also been developed within PROOSIS. However, a description of these methodologies is beyond the scope of this publication. Additionally, a comparison between the advantages and disadvantages between BETA and MFT maps is an interesting debate. However, this is also beyond the scope of this paper.

Assessing the Potential of Gas-Recuperation in Reheated Gas Turbines Within Combined Gas-Steam Power Plants

2014 ◽  
Author(s):  
Adam Doligalski ◽  
Luis Sanchez de Leon ◽  
Pavlos K. Zachos ◽  
Vassilios Pachidis
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Power Plants ◽  
Current Approach ◽  
Combined Cycle ◽  
Variable Position ◽  
Power Turbine ◽  
Power Generation Systems ◽  
Gas Turbine Cycle

This paper presents a comparative analysis between two different gas turbine configurations for implementation within combined cycle power plants, aiming to downselect the most promising one in terms of thermal efficiency at design point. The analysed gas turbines both feature the same dual-pressure steam bottoming cycle, but differ in the gas turbine cycle itself: the first configuration comprises a single-shaft reheated gas turbine with variable position of the reheater (representative of the current approach of the industry to combined cycle power plants), whilst the second configuration comprises a dual-shaft reheated-recuperated engine with free power turbine. Comparison of the two competing gas turbine configurations is conducted by means of systematic exploration of the combined cycle design space. The analysis showed that the reheated-recuperated configuration delivers higher thermal efficiency than the more conventional reheated (non-recuperated) gas turbine and is identified, therefore, as a competitive option for future combined cycle power generation systems.

Steady State Off-Design Performance of Humid Air Turbine Cycle

2007 ◽  
Author(s):  
Bo Wang ◽  
Shijie Zhang ◽  
Yunhan Xiao
Keyword(s):  
Steady State ◽  
Ambient Temperature ◽  
Gas Turbine ◽  
Humid Air ◽  
Part Load ◽  
Design Performance ◽  
Turbine Cooling ◽  
Air Turbine ◽  
Thermodynamic Performance ◽  
Gas Turbine Cycle

The Humid Air Turbine (HAT) cycle is recognized as a competitive innovative gas turbine cycle with good off-design thermodynamic performance. However, the off-design performance of the HAT cycle has not been sufficiently analyzed. In this paper, a steady state on-design and off-design thermodynamic performance investigation of the HAT cycle was presented by comparing the HAT cycle with other competitive gas turbine cycles. In order to perform energy analysis of various gas turbine cycles, a gas turbine cycle analysis system was developed, where the advanced detailed component models of the investigated cycles were built and integrated. A detailed turbine cooling model including various cooling methods was used to indicate the effects of the turbine cooling on the thermodynamic performance of the gas turbine cycles when the turbine inlet temperature is high. The model can also indicate changes in level of cooling technology. The saturator was simulated as a one-dimensional model which can be used to size the saturator at on-design condition and to investigate the thermodynamic performance of the saturator at off-design condition. The HAT cycle was compared with four different cycles for on-design and off-design thermodynamic performances: 1) simple cycle, 2) recuperated cycle (REC), 3) recuperated water injected (RWI) cycle and 4) steam injection gas turbine (STIG) cycle. The focus of the comparison was put on the thermodynamic off-design performance of the different gas turbine cycles. The effects of ambient temperature and load reduction (part-load at ISO conditions) on the thermodynamic performance of the simple, the recuperated, the RWI, the STIG and the HAT cycle were investigated and compared. The results indicate that the HAT cycle can recover the low grade heat efficiently and when ambient temperature increases, HAT cycle has the most favorable off-design performance. At part-load conditions, the off-design performance of HAT cycle is not so good as STIG cycle and simple cycle, but is better than the RWI cycle and recuperated cycle.

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