Design and Off-Design Characteristics of the Alternative Recuperated Gas Turbine Cycle With Divided Turbine Expansion

2006 ◽  
Author(s):  
Sung Hoon Hwang ◽  
Soo Hyung Yoon ◽  
Tong Seop Kim
Keyword(s):  
Mechanical Design ◽  
Pressure Ratio ◽  
Variable Speed ◽  
Part Load ◽  
Turbine Expansion ◽  
Compressor Pressure Ratio ◽  
Design Characteristics ◽  
Inlet Conditions ◽  
Design Analyses ◽  
Gas Turbine Cycle

In order to fully address the characteristics of the alternative recuperated cycle with divided turbine expansion, both the design and off-design analyses have been performed. Two types of mechanical design are assumed: two-shaft and single-shaft. In particular, optimal pressure ratio division between the high and low pressure turbines is evaluated for the single shaft configuration. It is predicted that the alternative recuperated cycle hardly exhibits sensible design efficiency advantage over the conventional recuperated cycle for moderate turbine inlet conditions and with usual component performances. An advantage of the alternative cycle with single shaft design is that thermal efficiency is less sensitive to compressor pressure ratio compared with other configurations and we can also have flexibility in the turbine division without much efficiency loss. The part load analyses have been carried out with the aid of realistic component maps and models for off-design operation. In addition to the general fuel only control, a variable speed control is assumed as the part load operating strategy of the single shaft configuration. Obvious advantage with the alternative cycle is observed in the variable speed operation of the single shaft design. With this strategy, the part load efficiency of the alternative cycle is far superior to the conventional cycle. Almost constant efficiency is predicted for a wide power range.

Design and Off-Design Characteristics of the Alternative Recuperated Gas Turbine Cycle With Divided Turbine Expansion

2006 ◽  
Vol 129 (2) ◽  
pp. 428-435 ◽  
Author(s):  
Sung Hoon Hwang ◽  
Soo Hyoung Yoon ◽  
Tong Seop Kim
Keyword(s):  
Mechanical Design ◽  
Pressure Ratio ◽  
Variable Speed ◽  
Part Load ◽  
Turbine Expansion ◽  
Compressor Pressure Ratio ◽  
Design Characteristics ◽  
Inlet Conditions ◽  
Design Analyses ◽  
Gas Turbine Cycle

In order to fully address the characteristics of the alternative recuperated cycle with divided turbine expansion, both design and off-design analyses have been performed. Two types of mechanical design are assumed: two shaft and single shaft. In particular, optimal pressure ratio division between the high- and low-pressure turbines is evaluated for the single-shaft configuration. It is predicted that the alternative recuperated cycle hardly exhibits sensible design efficiency advantage over the conventional recuperated cycle for moderate turbine inlet conditions and with usual component performances. An advantage of the alternative cycle with single-shaft design is that thermal efficiency is less sensitive to compressor pressure ratio compared to other configurations, and we can also have flexibility in the turbine division without much efficiency loss. The part load analyses have been carried out with the aid of realistic component maps and models for off-design operation. In addition to the general fuel only control, a variable speed control is assumed as the part load operating strategy of the single-shaft configuration. Obvious advantage with the alternative cycle is observed in the variable speed operation of the single-shaft design. With this strategy, the part load efficiency of the alternative cycle is far superior to the conventional cycle. Almost constant efficiency is predicted for a wide power range.

scholarly journals Off-Design Performance Comparison Between Single and Two-Shaft Engines: Part 1 — Fixed Geometry

2020 ◽  
Author(s):  
Th. Nikolaidis ◽  
A. Pellegrini ◽  
H. I. H. Saravanamuttoo ◽  
I. Aslanidou ◽  
A. Kalfas ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Mass Flow ◽  
Thermal Efficiency ◽  
Rotational Speed ◽  
Pressure Ratio ◽  
Performance Comparison ◽  
Part Load ◽  
Design Performance ◽  
Research Activities ◽  
Compressor Pressure Ratio

Abstract This paper describes an investigation into the off-design performance comparison of single and two-shaft gas turbine engines. A question that has been asked for a long time which gas turbine delivers a better thermal efficiency at part load. The authors, notwithstanding their intensive searches, were unable to find a comprehensive answer to this question. A detailed investigation was carried out using a state of the art performance evaluation method and the answer was found to be: It depends! In this work, the performance of two engine configurations is assessed. In the first one, the single-shaft gas turbine operates at constant shaft rotational speed. Thus, the shape of the compressor map rotational speed line will have an important influence on the performance of the engine. To explore the implications of the shape of the speed line, two single-shaft cases are examined. The first case is when the speed line is curved and as the compressor pressure ratio falls, the non-dimensional mass flow increases. The second case is when the speed line is vertical and as the compressor pressure ratio falls, the non-dimensional mass flow remains constant. In the second configuration, the two-shaft engine, the two-shafts can be controlled to operate at different rotational speeds and also varying relationships between the rotational speeds. The part-load operation is characterized by a reduction in the gas generator rotational speed. The tool, which was used in this study, is a 0-D whole engine simulation tool, named Turbomatch. It was developed at Cranfield and it is based on mass and energy balance, carried out through an iterative method, which is based on component maps. These generic, experimentally derived maps are scaled to match the design point of a particular engine before an off-design calculation is performed. The code has been validated against experimental data elsewhere, it has been used extensively for academic purposes and the research activities that have taken place at Cranfield University. For an ideal cycle, the single-shaft engine was found to be a clear winner in terms of part-load thermal efficiency. However, this picture changed when realistic component maps were utilized. The basic cycle and the shape of component maps had a profound influence on the outcome. The authors explored the influence of speed line shapes, levels of component efficiencies and the variation of these component efficiencies within the operating range. This paper describes how each one of these factors, individually, influences the outcome.

Thermodynamic and Energy Study of a Regenerator in Gas Turbine Cycle and Optimization of Performances

2016 ◽  
Vol 5 (2) ◽  
pp. 25-44
Author(s):  
Saria Abed ◽  
Taher Khir ◽  
Ammar Ben Brahim
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Parametric Study ◽  
Pressure Ratio ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Compressor Pressure Ratio ◽  
Compressor Inlet ◽  
Gas Turbine Cycle

In this paper, thermodynamic study of simple and regenerative gas turbine cycles is exhibited. Firstly, thermodynamic models for both cycles are defined; thermal efficiencies of both cycles are determined, the overall heat transfer coefficient through the heat exchanger is calculated in order to determinate its performances and parametric study is carried out to investigate the effects of compressor inlet temperature, turbine inlet temperature and compressor pressure ratio on the parameters that measure cycles' performance. Subsequently, numerical optimization is established through EES software to determinate operating conditions. The results of parametric study have shown a significant impact of operating parameters on the performance of the cycle. According to this study, the regeneration technique improves the thermal efficiency by 10%. The studied regenerator has an important effectiveness (˜ 82%) which improves the heat transfer exchange; also a high compressor pressure ratio and an important combustion temperature can increase thermal efficiency.

scholarly journals Investigation of the Pressure Gain Characteristics and Cycle Performance in Gas Turbines Based on Interstage Bleeding Rotating Detonation Combustion

Entropy ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 265 ◽  
Author(s):  
Lei Qi ◽  
Zhitao Wang ◽  
Ningbo Zhao ◽  
Yongqiang Dai ◽  
Hongtao Zheng ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Cycle Performance ◽  
Efficiency Enhancement ◽  
Compressor Pressure Ratio ◽  
Detonation Combustion ◽  
Gas Turbine Cycle ◽  
Cycle Efficiency ◽  
Rotating Detonation

To further improve the cycle performance of gas turbines, a gas turbine cycle model based on interstage bleeding rotating detonation combustion was established using methane as fuel. Combined with a series of two-dimensional numerical simulations of a rotating detonation combustor (RDC) and calculations of cycle parameters, the pressure gain characteristics and cycle performance were investigated at different compressor pressure ratios in the study. The results showed that pressure gain characteristic of interstage bleeding RDC contributed to an obvious performance improvement in the rotating detonation gas turbine cycle compared with the conventional gas turbine cycle. The decrease of compressor pressure ratio had a positive influence on the performance improvement in the rotating detonation gas turbine cycle. With the decrease of compressor pressure ratio, the pressurization ratio of the RDC increased and finally made the power generation and cycle efficiency enhancement rates display uptrends. Under the calculated conditions, the pressurization ratios of RDC were all higher than 1.77, the decreases of turbine inlet total temperature were all more than 19 K, the power generation enhancements were all beyond 400 kW and the cycle efficiency enhancement rates were all greater than 6.72%.

scholarly journals Analyses of Long-Term Off-Design Performance Strategy and Operation of a High-Pressure Ratio Intercooled Brayton Helium Gas Turbine Cycle for Generation IV Nuclear Power Plants

2018 ◽  
Vol 4 (4) ◽  
Author(s):  
A. Gad-Briggs ◽  
P. Pilidis ◽  
T. Nikolaidis
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Pressure Ratio ◽  
Pressure Losses ◽  
High Pressure Ratio ◽  
Compressor Pressure Ratio ◽  
Gas Turbine Cycle ◽  
Cycle Efficiency

The intercooled cycle (IC) is a simplified novel proposal for generation IV nuclear power plants (NPP) based on studies demonstrating efficiencies of over 45%. As an alternative to the simple cycle recuperated (SCR) and the intercooled cycle recuperated (ICR), the main difference in configuration is no recuperator, which reduces its size. It is expected that the components of the IC will not operate at optimum part power due to seasonal changes in ambient temperature and grid prioritization for renewable sources. Thus, the ability to demonstrate viable part load performance becomes an important requirement. The main objective of this study is to derive off-design points (ODPs) for a temperature range of −35 °C to 50 °C and core outlet temperatures (COTs) between 750 °C and 1000 °C. The ODPs have been calculated using a tool designed for this study. Based on the results, the intercooler changes the mass flow rate and compressor pressure ratio (PR). However, a drop of ∼9% in plant efficiency, in comparison to the ICR (6%) was observed for pressure losses of up to 5%. The reactor pressure losses for IC have the lowest effect on plant cycle efficiency in comparison to the SCR and ICR. Characteristic maps are created to support first-order calculations. It is also proposed to consider the intercooler pressure loss as a handle for ODP performance. The analyses brings attention to the IC an alternative cycle and aids development of cycles for generation IV NPPs specifically gas-cooled fast reactors (GFRs) and very-high-temperature reactors (VHTRs), using helium.

Improvements in Part-Load Efficiency by Reducing Pressure Ratio in Regenerative Gas-Turbine Engines

1985 ◽  
Author(s):  
Theodosios P. Korakianitis ◽  
David Gordon Wilson
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Heat Exchangers ◽  
Pressure Ratio ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Design Point ◽  
Part Load ◽  
Compressor Pressure Ratio ◽  
Point Pressure

To obtain equal thermal efficiencies in gas-turbine engines, designers have the freedom (if space and mass constraints are not limiting) of exchanging compressor pressure ratio for heat-exchanger effectiveness. Because heat exchangers can have lower losses than compressors, a high-effectiveness heat-exchanger cycle can have a much higher thermal efficiency (theoretically 55–60%) than is possible with unregenerated cycles. What has not been known up to now is the effect of design-point pressure ratio on the part-load efficiency of gas-turbine engines. The work reported here shows that, for similar turbomachinery technology, design-point and part-load efficiencies improve as the design-point pressure ratio decreases and the heat-exchanger thermal ratio increases.

USE OF VACUUM MICROGAS TURBINE PLANTS FOR HEATPOWER SUPPLY OF LOCAL OBJECTS

2020 ◽  
Vol 4 (1) ◽  
pp. 42-48
Author(s):  
A.V. DOLOGLONYAN ◽  
D.S. STREBKOV ◽  
V.T. MATVIIENKO ◽  
I.N. STACENKO
Keyword(s):  
Pressure Ratio ◽  
Simple Cycle ◽  
Specific Power ◽  
Ratio Increase ◽  
Turbine Expansion ◽  
Optimum Parameters ◽  
Compressor Pressure Ratio

Consideration subject in article are vacuum cycles of microgas turbine plants (MGTP) for the purpose of studying of their profitability and perspectives of use for heatpower supply of local objects. Vacuum MGTP of a simple cycle and with warmth regeneration is investigated. Optimum parameters of cycles – ratio of turbine expansion and regeneration ratio are found. It is established that profitability of MGTP with regeneration of warmth is higher in comparison with MGTP of a simple cycle almost twice, specific power decreases approximately by 1,35 times. By virtue of profitability and smaller values of compressor pressure ratio increase of the microturbine it is reasonable to apply in MGTP of a vacuum cycle with warmth regeneration.

Development of a High-Pressure-Ratio Axial Flow Compressor for a Medium-Size Gas Turbine

1986 ◽  
Vol 108 (2) ◽  
pp. 233-239 ◽  
Author(s):  
Y. Kashiwabara ◽  
Y. Matsuura ◽  
Y. Katoh ◽  
N. Hagiwara ◽  
T. Hattori ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Mechanical Design ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Axial Flow ◽  
Medium Size ◽  
High Pressure Ratio ◽  
Compressor Pressure Ratio ◽  
Predicted Values ◽  
Flow Compressor

In this paper, the development of a model 17-stage axial compressor (pressure ratio 14.7) for a medium-size gas turbine is described. The aerodynamic and mechanical design features of the compressor are presented. In advance of the full 17-stage test, the first three and nine stages were tested. Measured results confirm the design performance in the first stages of the 17-stage compressor. The details of the construction of the facilities, instrumentation and data acquisition system for the full 17-stage test are described. Test results for the 17-stage compressor are presented. The measured results are in good agreement with the predicted values.

A New High-Efficiency Heavy-Duty Combustion Turbine 701F

1994 ◽  
Vol 116 (2) ◽  
pp. 389-394 ◽  
Author(s):  
I. Fukue ◽  
S. Aoki ◽  
K. Aoyama ◽  
S. Umemura ◽  
A. Merola ◽  
...  
Keyword(s):  
High Efficiency ◽  
Pressure Ratio ◽  
Heavy Duty ◽  
Test Program ◽  
Testing Program ◽  
Industrial Grade ◽  
Design Changes ◽  
Compressor Pressure Ratio ◽  
Verification Test ◽  
Reliability Verification

The 701F is a high-temperature 50 Hz industrial grade 220 MW size engine based on a scaling of the 501F 150 MW class 60 Hz machine, and incorporates a higher compressor pressure ratio to increase the thermal efficiency. The prototype engine is under a two-year performance and reliability verification testing program at MHI’s Yokohama Plant and was initially fired in June of 1992. This paper describes the 701F design features design changes made from 501F. The associated performance and reliability verification test program will also be presented.

Recuperators in Gas Turbine Systems

1998 ◽  
Author(s):  
Esa Utriainen ◽  
Bengt Sundén
Keyword(s):  
Research And Development ◽  
Gas Turbine ◽  
Cross Sections ◽  
Heat Exchangers ◽  
Power Plants ◽  
Pressure Ratio ◽  
Compact Heat Exchangers ◽  
Thermodynamic Cycles ◽  
Large Pressure ◽  
Gas Turbine Cycle

The application of recuperators in advanced thermodynamic cycles is growing due to stronger demands of low emissions of pollutants and the necessity of improving the cycle efficiency of power plants to reduce the fuel consumption. This paper covers applications and types of heat exchangers used in gas turbine units. The trends of research and development are brought up and the future need for research and development is discussed. Material aspects are covered to some extent. Attempts to achieve compact heat exchangers for these applications are also discussed. With the increasing pressure ratio in the gas turbine cycle, large pressure differences between the hot and cold sides exist. This has to be accounted for. The applicability of CFD (Computational Fluid Dynamics) is discussed and a CFD–approach is presented for a specific recuperator. This recuperator has narrow wavy ducts with complex cross-sections and the hydraulic diameter is so small that laminar flow prevails. The thermal-hydraulic performance is of major concern.

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