Advanced Technologies for Gas Turbines (2020) / Chapter Skim
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3 High-Priority Research Areas and Topics
3 High-Priority Research Areas and Topics
Pages 39-100
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From page 39... ...
Likewise, as discussed throughout this chapter, the success of each research area is tied to the success of multiple other research areas.1 1 All but two of the research areas have three research topics. The Digital Twins and Their Supporting Infrastructure research area has one research topic, and the Gas Turbines in Pipeline Applications research area has two research topics.
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From page 40... ...
and oxyfuel combustion. This research area includes three research topics: • Fundamental Combustion Properties • Combustion Concepts to Reduce Harmful Emissions at Elevated Temperatures and Pressures • Operational and Performance Limits on Combustors Research Topic 1.1 Fundamental Combustion Properties Research Topic Summary Statement: Investigate fundamental combustion properties that control macro system emissions and operability characteristics for constant pressure and pressure gain combustors.
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From page 41... ...
While research around general questions of this nature is commonplace in the combustion community, there is little activity or data at conditions of interest for gas turbines because relevant facilities are expensive to maintain and operate and they require specialized staff to manage operational safety issues. For example, the higher temperatures and pressures associated with some techniques for improving efficiency are pushing combustion physics into regimes of combustion where fuel consumption occurs via autoignition.
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From page 42... ...
This challenge is also unique to gas turbine applications, as there are essentially no other technology platforms with combustion at these elevated temperatures and pressures. Background Historically, reducing NOx levels in gas turbines with turbine inlet temperatures less than about 1,500°C/2,800°F has been achieved through premixing of the fuel and air.
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From page 43... ...
This research topic applies to all gas turbine applications with turbine inlet temperatures higher than about 1,500°C/2,800°F in markets with NOx restrictions. Depending on the geographic region of the world, these NOx restrictions affect power generation, aviation, and oil and gas applications differently.
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From page 44... ...
This research topic could advance relevant technology from TRL 2 to TRL 7 by 2030. These topics are closely coupled to understanding the fundamental combustion properties outlined in Box 3.1.
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From page 45... ...
Better yet would be new combustion approaches that are less sensitive to uncertainties and variations in operating conditions and fuel composition. This research topic applies to power generation, aviation, and oil and gas turbine applications because the combustor inherently limits operational performance in all three applications.
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From page 46... ...
To attain current goals for thermal efficiency and fuel burn, advanced high-temperature technologies are required to enable higher temperatures in the hot gas path. This research area includes three research topics: • CMC Performance and Affordability • Physics-Based Lifing Models7 • Advanced Alloy Technologies The scope of all three research topics includes both static and rotating components.
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From page 47... ...
Gas turbines employ the Brayton cycle in their operation. A critical parameter for high thermal efficiency is the high cycle pressure ratio, which in turn drives high turbine flow path temperatures.
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From page 48... ...
Benefit As stated in the summary above, the benefits of higher quality CMCs include improved gas turbine efficiency as a result of higher operating temperatures and reduced cooling air requirements, as well as more efficient combustion, thereby reducing CO2 emissions.13 Reducing the costs of higher quality CMCs will enable them to be adopted earlier across a broader range applications. This research topic could accelerate ongoing research as follows: • Develop an optimum SiC fiber using cost-effective polymer processing routes that produce fiber with excellent strength retention, modulus, and creep-resistance properties with the key characteristics: stoichiometric ratio or carbon to silicon, protected grain boundaries, low residual oxygen content, and no foreign phases.
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From page 49... ...
Physics-based lifing models will be validated through laboratory testing that reliably and accurately predicts field performance. This research topic is critical for attaining and maintaining the thermal efficiency goals of future advanced gas turbines over their service life.
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From page 50... ...
In an aircraft gas turbine engine, failure of a high-pressure turbine blade can result in an unscheduled engine removal, potential disruption to service for the airline, and, in the worst case, flight safety risk. Analogous costs are incurred upon failure of a gas turbine in service for power generation or oil and gas applications.
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From page 51... ...
This research topic could advance relevant technology from TRL 3 to TRL 6 by 2030. The need to improve thermal efficiency in gas turbines will drive increased operating temperatures and exacerbate the impact of environmental distress.
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From page 52... ...
, doi:10.1038/s41524-017-0056-5. 23 There are some common elements to the development of new tools relevant to this research topic and those addressed in the section "Research Area 3: Additive Manufacturing for Gas Turbines," below.
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From page 53... ...
The most advanced high-temperature materials, such as single-crystal airfoils and advanced corrosion and thermal barrier coatings, are used in the high-pressure turbine and combustor, which are the highest temperature sections of the gas turbine. As the temperature of the main gas path of the gas turbine increases, advanced hightemperature material technologies will be needed in additional areas of the gas turbine.
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From page 54... ...
Benefit This research topic could accelerate ongoing research by providing the technology that is required to operate gas turbines at main gas path temperatures required to meet thermal efficiency goals. In addition, the successful development and utilization of advanced, high-temperature alloy technologies will be essential in meeting lifecycle cost goals by increasing gas turbine service life.
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From page 55... ...
Research areas that do not have a strong interrelationship with the structural materials and coatings research area are not shown. RESEARCH AREA 3: ADDITIVE MANUFACTURING FOR GAS TURBINES Research Area Summary Statement: Integrate model-based definitions of gas turbine materials (those already in use as well as advanced materials under development)
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From page 56... ...
Challenges for additive manufacturing of particular relevance to gas turbines include the ability to successfully manage potentially damaging process-induced phenomena such as increased distortion and cracking, print defects (e.g., lack of fusion 25 T.Wohlers and T Gornet, 2013, "History of Additive Manufacturing," Wohlers Report, http://wohlersassociates.com/history2013.pdf.
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From page 57... ...
This will require mastery of the complex physics of these printing processes, including high and rapidly varying temperature gradients, complex melt pool fluid flow phenomena, widely varying solidification morphologies, and residual stresses during the cooling process. This research area includes three research topics: • Integrated Design and Additive Manufacturing • Additive Manufacturing of High-Temperature Structural Materials • Integration of Sensors, Machine Learning, and Process Analytics Research Topic 3.1 Integrated Design and Additive Manufacturing Research Topic Summary Statement: Develop advanced methods for integrating models of materials, pro cesses, machines, and cost with computer-aided design (CAD)
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From page 58... ...
This research topic applies pervasively to gas turbines for power generation, aviation, and oil and gas applications because of the similarity in turbine component designs and the processes used to manufacture components. Research Topic 3.2 Additive Manufacturing of High-Temperature Structural Materials Research Topic Summary Statement: Develop new high-temperature structural materials and advanced additive manufacturing equipment and processes in order to raise the thermal efficiency and operating tem perature limits and increase the durability of gas turbine components produced using additive manufacturing; in addition, accelerate the qualification process for their application.
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From page 59... ...
A new combined test and simulation-based analysis approach to part qualification has been elusive, but it is essential to the rapid and cost-effective employment of high-temperature materials for additive manufacturing. Benefit This research topic could accelerate ongoing research in this area by focusing on the development of new additive manufacturing equipment capabilities and configurations.
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From page 60... ...
This research topic applies to power generation, aviation, and oil and gas applications because of similarities in relevant materials and component designs. Research Topic 3.3 Integration of Sensors, Machine Learning, and Process Analytics Research Topic Summary Statement: Integrate models of physics-based composition, processing, micro structures, and mechanical behavior with artificial intelligence (AI)
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From page 61... ...
However, advances in materials characterization techniques to inform model development and relevant global technology trends will mitigate the risks associated with the complexity. This research topic applies to gas turbines for power generation, aviation, and oil and gas applications because of the similarity in turbine component designs and the processes used to manufacture components.
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From page 62... ...
Subsequent development of high-temperature turbine materials, coatings, and cooling technologies have enabled turbine inlet temperatures of commercial transport engines at takeoff to increase from 1,000°C/1,850°F in the 1960s to more than 1,400°C/2,550°F in the 1990s. Modern gas turbines benefit from decades of impactful research on high-temperature alloys, advanced coatings, and improved cooling technologies.
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From page 63... ...
Because existing models are not able to accurately capture the complex, 3D thermal energy exchange between cooling film flows and the main gas path, the optimization of combustor and turbine cooling configurations is limited. Greater understanding is also needed regarding the effects of particle-laden flows entering the gas turbine from the external operating environment.33 Because of air pollution in some regions of the globe, particle-laden 33 Particle-laden flows affect the operation of gas turbines because the inlet supply air carries with it small particles that exist in the sur rounding environment.
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From page 64... ...
This research area includes three research topics: • Innovative Cooling • Full Conjugate Heat Transfer Models • Fundamental Physics and Modeling in Particle-Laden Flows Research Topic 4.1 Innovative Cooling Research Topic Summary Statement: Improve turbine component efficiencies through innovative cooling technologies and strategies. Summary Research to develop innovative cooling strategies needs to address the high temperatures and high mechanical stresses that turbine components experience as well as specific material properties and manufacturing methods.
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From page 65... ...
Benefit This research topic could accelerate ongoing research in innovative cooling strategies that enable higher turbine inlet temperatures, resulting in increased thermal efficiency while meeting life-cycle cost requirements. This research addresses a gap in the development of advanced cooling innovations in light of new high-temperature materials and additive manufacturing methods.
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From page 66... ...
Research Topic 4.2 Full Conjugate Heat Transfer Models Research Topic Summary Statement: Develop advanced full conjugate heat transfer techniques to enable the optimum design of combustor and turbine cooling configurations, which would minimize component cooling air flow, enable increased turbine inlet temperatures, and allow for higher cycle pressure ratios. Summary Conductive heat transfer is typically the dominant form of heat transfer in solids, while convective heat transfer typically dominates in liquids.
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From page 67... ...
This activity would require careful coordination among these key stakeholders. This research topic applies to power generation, aviation, and oil and gas applications for gas turbines operating at full and partial load.
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From page 68... ...
Unlike gas turbines for aircraft propulsion, gas turbines for both power generation and oil and gas applications can use filters to remove many larger particles (>10 μm) , but smaller particles remain in the main gas path flow.
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From page 69... ...
This research topic applies to aviation, power generation, and oil and gas applications, by providing a better understanding of how turbine operations are affected by particle-laden flows, which improves turbine cooling designs as well as lifing models needed. For the aviation applications, particle-laden flows can disrupt operations by requiring aircraft to detour around regions such as volcanic plumes or over developing countries with an especially high concentration of particles, increase engine wear, and possibly lead to a loss of propulsion in flight.
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From page 70... ...
This research area includes three research topics: • Numerical Simulation of Subsystems and System Integration • Coordinated Experimental Research • Computer Science and the Utility of Simulation Data Research Topic 5.1 Numerical Simulation of Subsystems and System Integration Research Topic Summary Statement: Develop advanced, high-fidelity, predictive numerical simulations to permit expanded exploration of design spaces and to enhance system-level optimization to support the development of gas turbines with higher efficiencies, reliability, and durability, and with lower develop ment costs. Summary Integrated numerical simulations can capture interactions among gas turbine modules.
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From page 71... ...
This research topic has moderate technical risk because of the issues that may have to be resolved with subgrid-scale models (e.g., turbulent combustion, liquid fuel atomization, and wall models for flow and heat transfer) that may surface as the simulations are applied to realistic gas turbines.
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From page 72... ...
in both the near and far field of the reaction zones. Benefit This research topic could accelerate ongoing research in this area by developing validated unresolved physics models, which would enable the assessment of subgrid-scale models and could reduce uncertainties in the results of numerical simulations.
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From page 73... ...
In addition to their utility in model development and validation of high-fidelity simulations, experimental data obtained in relevant conditions provide benchmarking platforms for mixed fidelity engineering models in all gas turbine applications. Research Topic 5.3 Computer Science and the Utility of Simulation Data Research Topic Summary Statement: Develop advanced methods for mapping high-fidelity numerical tools, including pre- and post-processing algorithms, to emerging computer architectures to facilitate the adoption of the high-fidelity simulation tools by gas turbine designers without specialized expertise in these methods.
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From page 74... ...
RESEARCH AREA 6: UNCONVENTIONAL THERMODYNAMIC CYCLES Research Area Summary Statement: Investigate and develop unconventional thermodynamic cycles for simple and combined cycle gas turbines to improve thermal efficiency, while ensuring that trade-offs with other elements of gas turbine performance, such as life-cycle cost, are acceptable. Overview The conventional approach for improving gas turbine efficiency relies on increasing cycle pressure ratio, increasing turbine inlet temperature, and improving the efficiency of individual turbine modules (compressor, combustor, and turbine)
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From page 75... ...
Cycles of potential interest include the following: • Pressure gain combustion cycle with simultaneous pressure and temperature rise in the combustor. In contrast, the Brayton cycle used by conventional gas turbines features constant-pressure combustion.
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From page 76... ...
This research area includes three research topics: • Gas Turbines with Pressure Gain Combustion: Technology • Gas Turbine Cycles for Carbon-Free Fuels • Gas Turbine Cycles with Inherent Carbon Capture Ability 48 In fact, pressure gain combustion and turbocompound cycles were originally conceived for aircraft propulsion applications.
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From page 77... ...
The specific PGC technology currently under investigation for aviation and power generation applications is detonation combustion. (An earlier version, pulsed detonation combustion, has been dropped in favor of the rotating detonation combustion due to the better amenability of the latter to quasi-steady flow applications.)
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From page 78... ...
This research topic applies to power generation, aviation, and oil and gas applications. Research Topic 6.2 Gas Turbine Cycles for Carbon-Free Fuels Research Topic Summary Statement: Develop gas turbine technology that would allow incorporation of unconventional Brayton cycle variants to achieve high thermal efficiency from combustion of carbon-free fuels such as hydrogen.
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From page 79... ...
This research topic could advance relevant technology from TRL 1 to TRL 3 by 2030. The research topic has high technical risk because, ultimately, regardless of the resources spent on it, a concept readily amenable to practical implementation may turn out to be unachievable.
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From page 80... ...
This research topic applies to stationary gas turbine applications -- more specifically, land-based gas turbines for electric power generation. (It is practically impossible to store or use captured carbon -- very difficult to achieve in the first place -- on a moving platform with extremely limited space.)
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From page 81... ...
and as yet unknown options. This research area includes three research topics: • Gas Turbines with Pressure Gain Combustion: System Layout • Closed Cycle Gas Turbines • Hybrid Gas Turbine Systems Research Topic 7.1 Gas Turbines with Pressure Gain Combustion: System Layout Research Topic Summary Statement: Develop an optimal layout for gas turbines with pressure gain com bustion that derives the maximum benefit from the total pressure rise generated by the combustor.
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From page 82... ...
Research Topic 7.2 Closed Cycle Gas Turbines Research Topic Summary Statement: Develop closed cycle gas turbine systems to maximize reliability, availability, and maintainability (RAM) and thermal efficiency when using external heat sources, such as solar and modular nuclear power plants, that eliminate carbon emissions.
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From page 83... ...
Research Topic 7.3 Hybrid Gas Turbine Systems Research Topic Summary Statement: Develop configurations for compact and cost-effective integration of Brayton cycle gas turbines with other technologies (e.g., fuel cells and reciprocating engines) for high thermal efficiency.
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From page 84... ...
This research topic could advance relevant technology from TRL 3 to TRL 7 by 2030 by reducing the system cost without hampering thermal efficiency or RAM. Despite the technical challenges involved, this research topic has medium technical risk primarily because of the large body of work done earlier.
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From page 85... ...
This required sensors, data acquisition systems, and data storage and analysis over the product life cycle. With gas turbines being closely monitored, both OEMs and owners started to exploit opportunities to reduce risk, operating and maintenance costs, and design margins through increasingly sophisticated analysis of sensor data.
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From page 86... ...
This research area includes three research topics: • Sensors • Inspection and Repair Technologies • Advanced Controls Research Topic 8.1 Sensors Research Topic Summary Statement: Develop reliable, high-capability, and low-cost sensors that will improve the accuracy of information gained about the health of gas turbines during operation. Summary Sensors for gas turbines face challenging requirements in terms of size, cost, temperature, pressure, reliability, and lifetime.
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From page 87... ...
This research topic applies to power generation, aviation, and oil and gas applications because the sensor requirements and challenges for all three gas turbine applications are similar. Research Topic 8.2 Inspection and Repair Technologies Research Topic Summary Statement: Develop in situ inspection and repair technologies to evaluate the degraded state of gas turbines, to maximize run time, and to minimize long-term maintenance costs.
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From page 88... ...
Benefit This research topic could accelerate ongoing research related to the following: • Miniaturization of sensor technology and end-effector technologies for inspection and repair to be introduced through borescope ports or other engine passages. • Enabling inspection and repair experts to work remotely from gas turbine site, thereby reducing the skill set required of local technicians.
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From page 89... ...
Regulatory changes may be required to redistribute responsibility and authority for inspections and repair using telepresence or teleoperation. This research topic applies to gas turbines for power generation, aviation, and oil and gas applications.
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From page 90... ...
This research topic applies primarily to power generation given that it is driven by requirements associated with the changing electrical grid. The results of this research topic, however, could also benefit gas turbines for aviation and oil and gas applications to the extent that improved control technologies developed would improve their ability to meet their system requirements.
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From page 91... ...
Research Topic 9.1 Digital Twins and the Digital Thread Research Topic Summary Statement: Develop digital twins and the supporting digital thread infrastructure that is specially designed to meet the needs of a gas turbine.
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From page 92... ...
Although concepts for digital twins and the digital thread have existed for many years, they are not widely implemented for gas turbines. The aviation industry is beginning to embrace digital twins for maintenance, repair, and overhaul,57 and OEMs are seeking to employ digital twins for power generation turbines.58 Recent advances in digitalization have created an environment that will enable the realization of this technology.
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From page 93... ...
This research topic applies to gas turbines for power generation, aviation, and oil and gas applications because they will all benefit from having advanced digital twins supported by a robust and reliable digital thread. This will ensure that all the pertinent data are fully utilized to support high-fidelity digital twins.
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From page 94... ...
This research area features two distinct research topics: • Efficiency of Pipeline Gas Turbines Under Partial Load • Safe Operation of Gas Turbines in Pipeline Applications with Hydrogen Fuels Research Topic 10.1 Efficiency of Pipeline Gas Turbines Under Partial Load Research Topic Summary Statement: Improve the efficiency of gas turbines for natural gas pipeline com pressor stations while operating under partial load and while maintaining high efficiency at peak load. Summary The focus of this research topic has been largely neglected mainly because compressor station operators do not need to pay for the natural gas in the pipeline that is diverted to the operation of the gas turbines in the compressor station.
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From page 95... ...
. Additive manufacturing provides methods to customize gas turbines for specific applications.
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From page 96... ...
This research topic applies to oil and gas and, potentially, to power generation applications. Research Topic 10.2 Safe Operation of Gas Turbines in Pipeline Applications with Hydrogen Fuels Research Topic Summary Statement: Develop the ability for gas turbines in pipeline applications to operate safely with varying levels of hydrogen (up to 100 percent)
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From page 97... ...
This research topic applies to oil and gas applications (particularly pipeline compressor stations driven by gas turbines) and, to a lesser extent, power generation.
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From page 98... ...
As shown, the different research areas are closely linked to one another, and efforts to support gas turbine research in different areas would be most effective if research plans are well coordinated.66 RECOMMENDATION: High-Priority Research Areas. In order to expedite the process of improving and creating advanced technologies that can be introduced into the design and manufacture of gas turbines, the Department of Energy (DOE)
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From page 99... ...
Develop advanced cooling strategies that can quickly and inexpensively be incorporated into gas turbines and enable higher turbine inlet temperatures, increased cycle pressure ratios, and lower combustor and turbine cooling flows, thereby yielding increased thermodynamic cycle efficiency while meeting gas turbine life requirements.
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From page 100... ...
Investigate (1) opportunities to improve the efficiency of Gas gas turbines in pipeline applications exposed to extended periods of partial load operation and (2)
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