Effects of Advanced Engine Technology on Open Rotor Cycle Selection and Performance

2012 ◽  
Author(s):  
Christopher A. Perullo ◽  
Jimmy C. M. Tai ◽  
Dimitri N. Mavris
Keyword(s):  
Fuel Efficiency ◽  
Sharp Decrease ◽  
Holistic Approach ◽  
Carbon Dioxide Production ◽  
Fuel Prices ◽  
Fuel Burn ◽  
Open Rotor ◽  
Institute Of Technology ◽  
Bypass Ratio ◽  
Rotor Model

Recent increases in fuel prices and increased focus on aviation’s environmental impacts have reignited focus on the open rotor engine concept. This type of architecture was extensively investigated in previous decades but was not pursued through to commercialization due to relatively high noise levels and a sudden, sharp decrease in fuel prices. More recent increases in fuel prices and increased government pressure from taxing carbon-dioxide production mean the open rotor is once again being investigated as a viable concept. Advances in aero-acoustic design tools have allowed industry and academia to re-investigate the open rotor with an increased emphasis on noise reduction while retaining the fuel burn benefits due to the increased propulsive efficiency. Recent research with conceptual level multidisciplinary considerations of the open rotor has been performed [1], but there remains a need for a holistic approach that includes the coupled effects of the engine and airframe on fuel burn, emissions, and noise. Years of research at Georgia Institute of Technology have led to the development of the Environmental Design Space (EDS) [2]. EDS serves to capture interdependencies at the conceptual design level of fuel burn, emissions, and noise for conventional and advanced engine and airframe architectures. Recently, leveraging NASA Environmentally Responsible Aviation (ERA) modeling efforts, EDS has been updated to include an open rotor model to capture, in an integrated fashion, the effects of an open rotor on conventional airframe designs. Due to the object oriented nature of EDS, the focus has been on designing modular elements that can be updated as research progresses. A power management scheme has also been developed with the future capability to trade between fuel efficiency and noise using the variable pitch propeller system. Since the original GE open rotor test was performed using a military core, there is interest in seeing the effect of modern core-engine technology on the integrated open rotor performance. This research applies the modular EDS open rotor model in an engine cycle study to investigate the sensitivity of thermal efficiency improvements on open rotor performance, including the effects on weight and vehicle performance. The results are that advances in the core cycle are necessary to enable future bypass ratio growth and the trades between core operating temperatures and size become more significant as bypass ratio continues to increase. A general benefit of a 30% reduction in block fuel is seen on a 737–800 sized aircraft.

Effects of Advanced Engine Technology on Open Rotor Cycle Selection and Performance

2013 ◽  
Vol 135 (7) ◽  
Author(s):  
Christopher A. Perullo ◽  
Jimmy C. M. Tai ◽  
Dimitri N. Mavris
Keyword(s):  
Design Space ◽  
Environmental Design ◽  
Sharp Decrease ◽  
Multidisciplinary Optimization ◽  
Fuel Prices ◽  
Fuel Burn ◽  
Open Rotor ◽  
Institute Of Technology ◽  
Bypass Ratio ◽  
Rotor Model

Recent increases in fuel prices and increased focus on aviation's environmental impacts have reignited focus on the open rotor engine concept. This type of architecture was extensively investigated in previous decades but was not pursued through to commercialization due to relatively high noise levels and a sudden, sharp decrease in fuel prices. More recent increases in fuel prices and increased government pressure from taxing carbon-dioxide production mean the open rotor is once again being investigated as a viable concept. Advances in aero-acoustic design tools have allowed industry and academia to re-investigate the open rotor with an increased emphasis on noise reduction while retaining the fuel burn benefits due to the increased propulsive efficiency. Recent research with conceptual level multidisciplinary considerations of the open rotor has been performed (Bellocq et al., 2010, “Advanced Open Rotor Performance Modeling For Multidisciplinary Optimization Assessments,” Paper No. GT2010-2963), but there remains a need for a holistic approach that includes the coupled effects of the engine and airframe on fuel burn, emissions, and noise. Years of research at Georgia Institute of Technology have led to the development of the Environmental Design Space (EDS) (Kirby and Mavris, 2008, “The Environmental Design Space,” Proceedings of the 26th International Congress of the Aeronautical Sciences). EDS serves to capture interdependencies at the conceptual design level of fuel burn, emissions, and noise for conventional and advanced engine and airframe architectures. Recently, leveraging NASA environmentally responsible aviation (ERA) modeling efforts, EDS has been updated to include an open rotor model to capture, in an integrated fashion, the effects of an open rotor on conventional airframe designs. Due to the object oriented nature of EDS, the focus has been on designing modular elements that can be updated as research progresses. A power management scheme has also been developed with the future capability to trade between fuel efficiency and noise using the variable pitch propeller system. Since the original GE open rotor test was performed using a military core, there is interest in seeing the effect of modern core-engine technology on the integrated open rotor performance. This research applies the modular EDS open rotor model in an engine cycle study to investigate the sensitivity of thermal efficiency improvements on open rotor performance, including the effects on weight and vehicle performance. The results are that advances in the core cycle are necessary to enable future bypass ratio growth and the trades between core operating temperatures and size become more significant as bypass ratio continues to increase. A general benefit of a 30% reduction in block fuel is seen on a 737-800 sized aircraft.

Performance Study for the Benefits of a Variable Pitch Composite Fan

2010 ◽  
Author(s):  
Robert S. Mazzawy
Keyword(s):  
New Technology ◽  
Fuel Efficiency ◽  
Performance Study ◽  
Full Spectrum ◽  
Variable Pitch ◽  
Fuel Burn ◽  
Power Setting ◽  
Fan Blade ◽  
And Performance ◽  
Bypass Ratio

This paper describes the installed performance potential for a recently patented new design concept for a variable pitch composite fan blade [1,2]. The unique characteristic of this design is the compactness and light weight of the assembly of fan plus variable pitch mechanism. This design enables turbofan engine cycles with higher propulsive efficiency that previously were not viable due to high installation weight and performance penalties. As part of its mandate to support new technology that improves fuel efficiency, the Connecticut Coalition for the Advancement of Technology (CCAT) sponsored a study to quantify the potential savings. A comparison is made between a current high bypass ratio engine and an advanced very high bypass ratio engine both configured to deliver approximately 30,000 lbs of thrust at the sea level static takeoff (SLTO) power setting. These engines are evaluated to determine the installed thrust and fuel consumption characteristics over the full spectrum of flight operation, enabling fuel burn to be evaluated for any aircraft mission. For a nominal mission profile considered in this paper, the advanced engine cycle enabled by the use of the variable pitch composite fan blade provided more than 12% reduction in fuel burn.

scholarly journals Modeling Geared Turbofan and Open Rotor Engine Performance for Year-2050 Long-Range and Short-Range Aircraft

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Francesco S. Mastropierro ◽  
Joshua Sebastiampillai ◽  
Florian Jacob ◽  
Andrew Rolt
Keyword(s):  
Short Range ◽  
Pressure Ratio ◽  
Engine Performance ◽  
Optimized Design ◽  
Fuel Burn ◽  
Medium Range ◽  
Open Rotor ◽  
And Performance ◽  
Year 2000 ◽  
Bypass Ratio

Abstract This paper provides design and performance data for two envisaged year-2050 engines: a geared high bypass turbofan for intercontinental missions and a contra-rotating pusher open rotor targeting short to medium range aircraft. It defines component performance and cycle parameters, general arrangements, sizes, and weights. Reduced thrust requirements reflect expected improvements in engine and airframe technologies. Advanced simulation platforms have been developed to model the engines and details of individual components. The engines are optimized and compared with “baseline” year-2000 turbofans and an anticipated year-2025 open rotor to quantify the relative fuel-burn benefits. A preliminary scaling with year-2050 “reference” engines, highlights tradeoffs between reduced specific fuel consumption (SFC) and increased engine weight and diameter. These parameters are converted into mission fuel burn variations using linear and nonlinear trade factors (NLTF). The final turbofan has an optimized design-point bypass ratio (BPR) of 16.8, and a maximum overall pressure ratio (OPR) of 75.4, for a 31.5% TOC thrust reduction and a 46% mission fuel burn reduction per passenger kilometer compared to the respective “baseline” engine–aircraft combination. The open rotor SFC is 9.5% less than the year-2025 open rotor and 39% less than the year-2000 turbofan, while the TOC thrust increases by 8% versus the 2025 open rotor, due to assumed increase in passenger capacity. Combined with airframe improvements, the final open rotor-powered aircraft has a 59% fuel-burn reduction per passenger kilometer relative to its baseline.

scholarly journals Modelling Geared Turbofan and Open Rotor Engine Performance for Year-2050 Long-Range and Short-Range Aircraft

2019 ◽  
Author(s):  
Joshua Sebastiampillai ◽  
Florian Jacob ◽  
Francesco S. Mastropierro ◽  
Andrew Rolt
Keyword(s):  
State Of The Art ◽  
Pressure Ratio ◽  
Engine Performance ◽  
Fuel Burn ◽  
Trade Offs ◽  
Medium Range ◽  
Open Rotor ◽  
And Performance ◽  
Year 2000 ◽  
Bypass Ratio

Abstract The paper provides design and performance data for two envisaged year-2050 state-of-the-art engines: a geared high bypass turbofan for intercontinental missions and a contra-rotating pusher open rotor targeting short to medium range aircraft. It defines component performance and cycle parameters, general powerplant arrangements, sizes and weights. Reduced thrust requirements for future aircraft reflect expected improvements in engine and airframe technologies. Advanced simulation platforms have been developed, using the software PROOSIS, to model the engines and details of individual components, including custom elements for the open rotor engine. The engines are optimised and compared with ‘baseline’ year-2000 turbofans and an anticipated year-2025 entry-into-service open rotor to quantify the relative fuel-burn benefits. A preliminary scaling with non-optimised year-2050 ‘reference’ engines, based on Top-of-Climb (TOC) thrust and bypass ratio, highlights the trade-offs between reduced specific fuel consumption (SFC) and increased weight and engine diameter. These parameters are then converted into mission fuel burn using linear and non-linear trade factors from aircraft models. The final turbofan has an optimised design-point bypass ratio (BPR) of 16.8, and a maximum overall pressure ratio (OPR) of 75.4 for a 31.5% TOC thrust reduction and a 46% mission fuel burn reduction per passenger kilometre compared to the respective year-2000 baseline engine and aircraft combination. The final open rotor SFC is 9.5% less than the year-2025 open rotor and 39% less than the year-2000 turbofan, while the TOC thrust increases by 8% versus the 2025 open rotor, due to assumed increase in aircraft passenger capacity. Combined with airframe improvements, the final open rotor-powered aircraft has a 59% fuel-burn reduction per passenger kilometre relative to its year-2000 baseline.

CAEP/9-agreed certification requirement for the Aeroplane CO2Emissions Standard: a comment on ICAO Cir 337

2016 ◽  
Vol 120 (1226) ◽  
pp. 693-723 ◽  
Author(s):  
J.E. Green ◽  
J.A. Jupp
Keyword(s):  
Fuel Efficiency ◽  
Scientific Basis ◽  
Civil Aviation ◽  
Aircraft Emissions ◽  
Current Form ◽  
Fuel Burn ◽  
Aircraft Fuel ◽  
Starting Point ◽  
Range Equation ◽  
Main Criticism

ABSTRACTThe International Civil Aviation Organization (ICAO) Circular Cir 337 is the first step towards ICAO establishing an Aeroplane CO2Emissions Standard to form part of Annex 16, Volume III to the Chicago Convention. It describes itself as ‘a work in progress’. This paper reviews Cir 337 against the background of flight physics, the published literature on aircraft fuel burn and CO2emissions and the current practices of the aircraft and engine manufacturers and the airline operators. We have taken, as our starting point, the aim of ICAO to reduce the fuel used per revenue tonne-kilometre performed and argue that the Breguet range equation, which captures all the relevant flight physics, should be the basis of the metric system underpinning the standard. Our overall conclusion is that Cir 337 provides an excellent basis for the initial regulation of aviation's CO2emissions and, further in the future, for developing measures to increase the fuel efficiency of the operational side of civil aviation. Our main criticism of the circular in its current form is that it does not address the ICAO goal of reducingfuel used per revenue tonne-kilometre performedand makes no reference to payload. This defect could be eliminated simply by omission of the exponent 0.24 of the Reference Geometric Factor (RGF) in the formula for the metric given in Chapter 2 (paragraph 2.2) of the circular. Retaining theRGFto the power unity in the metric and multiplying it by an appropriate value of the effective floor loading would convert it to what the 37thAssembly of ICAO called for – a statement of fuel used per revenue tonne-kilometre performed. Finally, correlating the amended metric against design range, as determined from the measured specific air range and the key certificated masses, provides a sound scientific basis for an initial regulation to cap passenger aircraft emissions.

Ultra High Bypass Ratio Engine Sizing and Cycle Selection Study for a Subsonic Commercial Aircraft in the N+2 Timeframe

2011 ◽  
Author(s):  
Brian K. Kestner ◽  
Jeff S. Schutte ◽  
Jonathan C. Gladin ◽  
Dimitri N. Mavris
Keyword(s):  
Pressure Ratio ◽  
Important Variable ◽  
Direct Drive ◽  
Commercial Aircraft ◽  
Low Pressure Turbine ◽  
Fuel Burn ◽  
Technology Transition ◽  
Fundamental Research ◽  
Bypass Ratio ◽  
Engine Cycle

This paper presents an engine sizing and cycle selection study of ultra high bypass ratio engines applied to a subsonic commercial aircraft in the N+2 (2020) timeframe. NASA has created the Environmentally Responsible Aviation (ERA) project to serve as a technology transition bridge between fundamental research (TRL 1–4) and potential users (TRL 7). Specifically, ERA is focused on subsonic transport technologies that could reach TRL 6 by 2020 and are capable of integration into an advanced vehicle concept that simultaneously meets the ERA project metrics for noise, emissions, and fuel burn. An important variable in exploring the trade space is the selection of the optimal engine cycle for use on the advanced aircraft. In this paper, two specific ultra high bypass engine cycle options will be explored: advanced direct drive and geared turbofan. The advanced direct drive turbofan is an improved version of conventional turbofans. In terms of both bypass ratio and overall pressure ratio, the advanced direct turbofan benefits from improvements in aerodynamic design of its components, as well as material stress and temperature properties. By putting a gear between the fan and the low pressure turbine, a geared turbo fan allows both components to operate at optimal speeds, thus further improving overall cycle efficiency relative to a conventional turbofan. In this study, sensitivity of cycle design with level of technology will be explored, in terms of both cycle parameters (such as specific thrust consumption (TSFC) and bypass ratio) and aircraft mission parameters (such as fuel burn and noise). To demonstrate this sensitivity, engines will be sized for optimal performance on a 300 passenger class aircraft for a 2010 level technology tube and wing airframe, a N+2 level technology tube and wing air-frame, and finally on a N+2 level technology blended wing body airframe with and without boundary layer ingestion (BLI) engines.

scholarly journals Are the new fuel-efficient bulkers a threat to the old fleet?

2017 ◽  
Vol 2 (3) ◽  
pp. 224-246 ◽  
Author(s):  
Jeroen Pruyn
Keyword(s):  
Design Methodology ◽  
Fuel Efficiency ◽  
Content Type ◽  
Business Opportunity ◽  
Fuel Prices ◽  
Delivery Times ◽  
Low Emission ◽  
Large Fluctuations ◽  
History Of ◽  
Energy Efficiency Design Index

Purpose The purpose of this paper is to investigate whether the headlined eco-bulkers ordered in 2012 and 2013 are posing a threat to the less-efficient ships ordered at the end of the boom in 2008 and 2009. Design/methodology/approach This paper will first investigate the drivers for the interest in such low-emission, low-speed bulker as well as the more general history of bulker designs. This is followed by a study on the vessels delivered between 2005 and 2014, based on eight parameters representing fuel efficiency, speed and hydromechanics properties. Within these results, evidence is sought for a significant change in the qualities of the vessels delivered after the last boom. Findings The data showed that at least till present, no significant changes could be discovered between 2014 and the earlier years. This indicates that either because of the long delivery times at the end of the boom, such vessels are still to be delivered, or that they were not ordered in an amount large enough to change the trend. For the future, this fact and the changes in vessel design resulting from the introduction of the energy efficiency design index (EEDI) in 2017 and the large fluctuations in the fuel prices will be interesting to keep monitoring the developments in the eight studied parameters. Originality/value This paper extends (in time) and improves (number of variables studied) a number of earlier studies on average qualities of the world fleet. It studies both the composition and the changes in average properties of the ships produced each year. It allowed the author to discover and explain the trends that would not have been evident when studying ships as single units or as the result of a business opportunity optimisation. Most important of which is the fact that, on average, ships produced are optimised for the current economic conditions and are not taken into consideration for future trends and scenarios.

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