The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
Jeffrey J. Berton - One of the best experts on this subject based on the ideXlab platform.
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Advanced Single-Aisle Transport Propulsion Design Options Revisited
2013 Aviation Technology Integration and Operations Conference, 2013Co-Authors: Mark D. Guynn, Jeffrey J. Berton, Michael T. Tong, William J. HallerAbstract:Future propulsion options for advanced single-aisle transports have been investigated in a number of previous studies by the authors. These studies have examined the system level characteristics of aircraft incorporating ultra-high bypass ratio (UHB) turboFans (direct drive and geared) and open rotor engines. During the course of these prior studies, a number of potential refinements and enhancements to the analysis methodology and assumptions were identified. This paper revisits a previously conducted UHB turboFan Fan Pressure ratio trade study using updated analysis methodology and assumptions. The changes in propulsion, airframe, and noise modeling are described and discussed. The impacts of these changes are then examined by comparison to the previously reported results. The changes incorporated have decreased the optimum Fan Pressure ratio for minimum fuel consumption and reduced the engine design trade-offs between minimizing noise and minimizing fuel consumption. Nacelle drag and engine weight are found to be key drivers in determining the optimum Fan Pressure ratio from a fuel efficiency perspective. The revised noise analysis results in the study aircraft being 2 to 4 EPNdB (cumulative) quieter due to a variety of reasons explained in the paper. With equal core technology assumed, the geared engine architecture is found to be as good as or better than the direct drive architecture for most parameters investigated. However, the engine ultimately selected for a future advanced single-aisle aircraft will depend on factors beyond those considered here.
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Refined Exploration of TurboFan Design Options for an Advanced Single-Aisle Transport
2011Co-Authors: Mark D. Guynn, Jeffrey J. Berton, Michael T. Tong, William J. Haller, Kenneth L. Fisher, Douglas R. ThurmanAbstract:Abstract The desire for higher engine efficiency has resulted in the evolution of aircraft gas turbine engines from turbojets, to low bypass ratio, first generation turboFans, to today’s high bypass ratio turboFans. It is possible that future designs will continue this trend, leading to very-high or ultra-high bypass ratio engines. A comprehensive exploration of the turboFan engine design space for an advanced technology single-aisle transport (737/A320 class aircraft) was conducted previously by the authors and is documented in a prior report. Through the course of that study and in a subsequent evaluation of the approach and results, a number of enhancements to the engine design ground rules and assumptions were identified. A follow-on effort was initiated to investigate the impacts of these changes on the original study results. The fundamental conclusions of the prior study were found to still be valid with the revised engine designs. The most significant impact of the design changes was a reduction in the aircraft weight and block fuel penalties incurred with low Fan Pressure ratio, ultra-high bypass ratio designs. This enables lower noise levels to be pursued (through lower Fan Pressure ratio) with minor negative impacts on aircraft weight and fuel efficiency. Regardless of the engine design selected, the results of this study indicate the potential for the advanced aircraft to realize substantial improvements in fuel efficiency, emissions, and noise compared to the current vehicles in this size class.
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Multi-Objective Optimization of TurboFan Design Parameters for an Advanced, Single-Aisle Transport
10th AIAA Aviation Technology Integration and Operations (ATIO) Conference, 2010Co-Authors: Jeffrey J. Berton, Mark D. GuynnAbstract:Considerable interest surrounds the design of the next generation of single-aisle commercial transports in the Boeing 737 and Airbus A320 class. Aircraft designers will depend on advanced, next-generation turboFan engines to power these airplanes. The focus of this study is to apply singleand multi-objective optimization algorithms to the conceptual design of ultrahigh bypass (UHB) turboFan engines for this class of aircraft, using NASA’s Subsonic Fixed Wing Project goals as multidisciplinary objectives for optimization. The independent propulsion design parameters investigated are aerodynamic design point Fan Pressure ratio, overall Pressure ratio, Fan drive system architecture (i.e., director geardriven), bypass nozzle architecture (i.e., fixedor variable-geometry), and the highand lowPressure compressor work split. NASA Project goal metrics – fuel burn, noise, and emissions – are among the parameters treated as dependent objective functions. These optimized solutions provide insight to the UHB engine design process and provide independent information to NASA program management to help guide its technology development efforts. This assessment leverages results from earlier NASA system concept studies conducted in 2008 and 2009, in which UHB turboFans were examined for a notional, nextgeneration, single-aisle transport. The purpose of these NASA UHB engine concept studies is to determine if the fuel consumption and noise benefits of engines having lower Fan Pressure ratios (and correspondingly higher bypass ratios) translate into overall aircraft system-level benefits for a 737 class vehicle.
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Advanced Engine Cycles Analyzed for TurboFans With Variable-Area Fan Nozzles Actuated by a Shape Memory Alloy
2002Co-Authors: Jeffrey J. BertonAbstract:Advanced, large commercial turboFan engines using low-Fan-Pressure-ratio, very high bypass ratio thermodynamic cycles can offer significant fuel savings over engines currently in operation. Several technological challenges must be addressed, however, before these engines can be designed. To name a few, the high-diameter Fans associated with these engines pose a significant packaging and aircraft installation challenge, and a large, heavy gearbox is often necessary to address the differences in ideal operating speeds between the Fan and the low-Pressure turbine. Also, the large nacelles contribute aerodynamic drag penalties and require long, heavy landing gear when mounted on conventional, low wing aircraft. Nevertheless, the reduced fuel consumption rates of these engines are a compelling economic incentive, and Fans designed with low Pressure ratios and low tip speeds offer attractive noise-reduction benefits. Another complication associated with low-Pressure-ratio Fans is their need for variable flow-path geometry. As the design Fan Pressure ratio is reduced below about 1.4, an operational disparity is set up in the Fan between high and low flight speeds. In other words, between takeoff and cruise there is too large a swing in several key Fan parameters-- such as speed, flow, and Pressure--for a Fan to accommodate. One solution to this problem is to make use of a variable-area Fan nozzle (VAFN). However, conventional, hydraulically actuated variable nozzles have weight, cost, maintenance, and reliability issues that discourage their use with low-Fan-Pressure-ratio engine cycles. United Technologies Research, in cooperation with NASA, is developing a revolutionary, lightweight, and reliable shape memory alloy actuator system that can change the on-demand nozzle exit area by up to 20 percent. This "smart material" actuation technology, being studied under NASA's Ultra-Efficient Engine Technology (UEET) Program and Revolutionary Concepts in Aeronautics (RevCon) Program, has the potential to enable the next generation of efficient, quiet, very high bypass ratio turboFans. NASA Glenn Research Center's Propulsion Systems Analysis Office, along with NASA Langley Research Center's Systems Analysis Branch, conducted an independent analytical assessment of this new technology to provide strategic guidance to UEET and RevCon. A 2010-technology-level high-spool engine core was designed for this evaluation. Two families of low-spool components, one with and one without VAFN's, were designed to operate with the core. This "constant core" approach was used to hold most design parameters constant so that any performance differences between the VAFN and fixed nozzle cycles could be attributed to the VAFN technology alone. In this manner, the cycle design regimes that offer a performance payoff when VAFN's are used could be identified. The NASA analytical model of a performance-optimized VAFN turboFan with a Fan Pressure ratio of 1.28 is shown. Mission analyses of the engines were conducted using the notional, long-haul, advanced commercial twinjet shown. A high wing design was used to accommodate the large high-bypassratio engines. The mission fuel reduction benefit of very high bypass shape-memory-alloy VAFN aircraft was calculated to be 8.3 percent lower than a moderate bypass cycle using a conventional fixed nozzle. Shape-memory-alloy VAFN technology is currently under development in NASA's UEET and RevCon Programs.
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Comparison of turbine bypass and mixed flow turboFan engines for a high-speed civil transport
Aircraft Design and Operations Meeting, 1991Co-Authors: Jonathan A. Seidel, William J. Haller, Jeffrey J. BertonAbstract:A comparison of the turbine bypass engine and the mixed flow turboFan for a Mach 2.4 cruise application is presented. A parametric assessment is conducted for each cycle. Parameters that are investigated for the turbine bypass engine include design bypass, combustor exit temperature, and overall Pressure ratio. Parameters that are investigated for the mixed flow turboFan include Fan Pressure ratio, mixer design Pressure ratio, and combustor exit temperature. The engines are analyzed for a 5000-nautical-mile, all supersonic cruise mission to determine the aircraft takeoff gross weights. The effects of takeoff noise, cruise emissions, the addition of subsonic cruise legs, and constrained supersonic cruise altitudes are also evaluated.
Martin Heinrich - One of the best experts on this subject based on the ideXlab platform.
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A Model for Stall and Surge in Low-Speed Contra-Rotating Fans
Journal of Engineering for Gas Turbines and Power, 2019Co-Authors: Mohammad Javad Shahriyari, Hossein Khaleghi, Martin HeinrichAbstract:This paper reports on a theory for poststall transients in contra-rotating Fans, which is developed from the basic Moore–Greitzer theory. A second-order hysteresis term is assumed for the Fan Pressure rise, which gives the theory more capabilities in predicting the Fan instabilities. The effect of the rotational speed ratio of the two counter rotating rotors on the Fan performance during the occurrence of surge and rotating stall are studied (the rotational speed of the front rotor is assumed to be kept constant whereas the speed of the rear rotor is variable). One of the new capabilities of the current model is the possibility of investigating the effect of the initial slope on the Fan characteristic. Results reveal that unlike the conventional Fans and compressors, in the current contra-rotating Fan stall cannot be initiated from the negative slope portion of the Fan Pressure rise characteristic curve. One of the important advantages of the developed model is that it enables investigation of the effect of the rate of throttling on the instabilities. Results show that more the rotational speed of the rear rotor, the more robust to surge (caused by throttling) the Fan is.
Mark D. Guynn - One of the best experts on this subject based on the ideXlab platform.
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Advanced Single-Aisle Transport Propulsion Design Options Revisited
2013 Aviation Technology Integration and Operations Conference, 2013Co-Authors: Mark D. Guynn, Jeffrey J. Berton, Michael T. Tong, William J. HallerAbstract:Future propulsion options for advanced single-aisle transports have been investigated in a number of previous studies by the authors. These studies have examined the system level characteristics of aircraft incorporating ultra-high bypass ratio (UHB) turboFans (direct drive and geared) and open rotor engines. During the course of these prior studies, a number of potential refinements and enhancements to the analysis methodology and assumptions were identified. This paper revisits a previously conducted UHB turboFan Fan Pressure ratio trade study using updated analysis methodology and assumptions. The changes in propulsion, airframe, and noise modeling are described and discussed. The impacts of these changes are then examined by comparison to the previously reported results. The changes incorporated have decreased the optimum Fan Pressure ratio for minimum fuel consumption and reduced the engine design trade-offs between minimizing noise and minimizing fuel consumption. Nacelle drag and engine weight are found to be key drivers in determining the optimum Fan Pressure ratio from a fuel efficiency perspective. The revised noise analysis results in the study aircraft being 2 to 4 EPNdB (cumulative) quieter due to a variety of reasons explained in the paper. With equal core technology assumed, the geared engine architecture is found to be as good as or better than the direct drive architecture for most parameters investigated. However, the engine ultimately selected for a future advanced single-aisle aircraft will depend on factors beyond those considered here.
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Refined Exploration of TurboFan Design Options for an Advanced Single-Aisle Transport
2011Co-Authors: Mark D. Guynn, Jeffrey J. Berton, Michael T. Tong, William J. Haller, Kenneth L. Fisher, Douglas R. ThurmanAbstract:Abstract The desire for higher engine efficiency has resulted in the evolution of aircraft gas turbine engines from turbojets, to low bypass ratio, first generation turboFans, to today’s high bypass ratio turboFans. It is possible that future designs will continue this trend, leading to very-high or ultra-high bypass ratio engines. A comprehensive exploration of the turboFan engine design space for an advanced technology single-aisle transport (737/A320 class aircraft) was conducted previously by the authors and is documented in a prior report. Through the course of that study and in a subsequent evaluation of the approach and results, a number of enhancements to the engine design ground rules and assumptions were identified. A follow-on effort was initiated to investigate the impacts of these changes on the original study results. The fundamental conclusions of the prior study were found to still be valid with the revised engine designs. The most significant impact of the design changes was a reduction in the aircraft weight and block fuel penalties incurred with low Fan Pressure ratio, ultra-high bypass ratio designs. This enables lower noise levels to be pursued (through lower Fan Pressure ratio) with minor negative impacts on aircraft weight and fuel efficiency. Regardless of the engine design selected, the results of this study indicate the potential for the advanced aircraft to realize substantial improvements in fuel efficiency, emissions, and noise compared to the current vehicles in this size class.
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Multi-Objective Optimization of TurboFan Design Parameters for an Advanced, Single-Aisle Transport
10th AIAA Aviation Technology Integration and Operations (ATIO) Conference, 2010Co-Authors: Jeffrey J. Berton, Mark D. GuynnAbstract:Considerable interest surrounds the design of the next generation of single-aisle commercial transports in the Boeing 737 and Airbus A320 class. Aircraft designers will depend on advanced, next-generation turboFan engines to power these airplanes. The focus of this study is to apply singleand multi-objective optimization algorithms to the conceptual design of ultrahigh bypass (UHB) turboFan engines for this class of aircraft, using NASA’s Subsonic Fixed Wing Project goals as multidisciplinary objectives for optimization. The independent propulsion design parameters investigated are aerodynamic design point Fan Pressure ratio, overall Pressure ratio, Fan drive system architecture (i.e., director geardriven), bypass nozzle architecture (i.e., fixedor variable-geometry), and the highand lowPressure compressor work split. NASA Project goal metrics – fuel burn, noise, and emissions – are among the parameters treated as dependent objective functions. These optimized solutions provide insight to the UHB engine design process and provide independent information to NASA program management to help guide its technology development efforts. This assessment leverages results from earlier NASA system concept studies conducted in 2008 and 2009, in which UHB turboFans were examined for a notional, nextgeneration, single-aisle transport. The purpose of these NASA UHB engine concept studies is to determine if the fuel consumption and noise benefits of engines having lower Fan Pressure ratios (and correspondingly higher bypass ratios) translate into overall aircraft system-level benefits for a 737 class vehicle.
William J. Haller - One of the best experts on this subject based on the ideXlab platform.
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Advanced Single-Aisle Transport Propulsion Design Options Revisited
2013 Aviation Technology Integration and Operations Conference, 2013Co-Authors: Mark D. Guynn, Jeffrey J. Berton, Michael T. Tong, William J. HallerAbstract:Future propulsion options for advanced single-aisle transports have been investigated in a number of previous studies by the authors. These studies have examined the system level characteristics of aircraft incorporating ultra-high bypass ratio (UHB) turboFans (direct drive and geared) and open rotor engines. During the course of these prior studies, a number of potential refinements and enhancements to the analysis methodology and assumptions were identified. This paper revisits a previously conducted UHB turboFan Fan Pressure ratio trade study using updated analysis methodology and assumptions. The changes in propulsion, airframe, and noise modeling are described and discussed. The impacts of these changes are then examined by comparison to the previously reported results. The changes incorporated have decreased the optimum Fan Pressure ratio for minimum fuel consumption and reduced the engine design trade-offs between minimizing noise and minimizing fuel consumption. Nacelle drag and engine weight are found to be key drivers in determining the optimum Fan Pressure ratio from a fuel efficiency perspective. The revised noise analysis results in the study aircraft being 2 to 4 EPNdB (cumulative) quieter due to a variety of reasons explained in the paper. With equal core technology assumed, the geared engine architecture is found to be as good as or better than the direct drive architecture for most parameters investigated. However, the engine ultimately selected for a future advanced single-aisle aircraft will depend on factors beyond those considered here.
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Refined Exploration of TurboFan Design Options for an Advanced Single-Aisle Transport
2011Co-Authors: Mark D. Guynn, Jeffrey J. Berton, Michael T. Tong, William J. Haller, Kenneth L. Fisher, Douglas R. ThurmanAbstract:Abstract The desire for higher engine efficiency has resulted in the evolution of aircraft gas turbine engines from turbojets, to low bypass ratio, first generation turboFans, to today’s high bypass ratio turboFans. It is possible that future designs will continue this trend, leading to very-high or ultra-high bypass ratio engines. A comprehensive exploration of the turboFan engine design space for an advanced technology single-aisle transport (737/A320 class aircraft) was conducted previously by the authors and is documented in a prior report. Through the course of that study and in a subsequent evaluation of the approach and results, a number of enhancements to the engine design ground rules and assumptions were identified. A follow-on effort was initiated to investigate the impacts of these changes on the original study results. The fundamental conclusions of the prior study were found to still be valid with the revised engine designs. The most significant impact of the design changes was a reduction in the aircraft weight and block fuel penalties incurred with low Fan Pressure ratio, ultra-high bypass ratio designs. This enables lower noise levels to be pursued (through lower Fan Pressure ratio) with minor negative impacts on aircraft weight and fuel efficiency. Regardless of the engine design selected, the results of this study indicate the potential for the advanced aircraft to realize substantial improvements in fuel efficiency, emissions, and noise compared to the current vehicles in this size class.
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Comparison of turbine bypass and mixed flow turboFan engines for a high-speed civil transport
Aircraft Design and Operations Meeting, 1991Co-Authors: Jonathan A. Seidel, William J. Haller, Jeffrey J. BertonAbstract:A comparison of the turbine bypass engine and the mixed flow turboFan for a Mach 2.4 cruise application is presented. A parametric assessment is conducted for each cycle. Parameters that are investigated for the turbine bypass engine include design bypass, combustor exit temperature, and overall Pressure ratio. Parameters that are investigated for the mixed flow turboFan include Fan Pressure ratio, mixer design Pressure ratio, and combustor exit temperature. The engines are analyzed for a 5000-nautical-mile, all supersonic cruise mission to determine the aircraft takeoff gross weights. The effects of takeoff noise, cruise emissions, the addition of subsonic cruise legs, and constrained supersonic cruise altitudes are also evaluated.
Becky Rose - One of the best experts on this subject based on the ideXlab platform.
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Ultrashort Nacelles for Low Fan Pressure Ratio Propulsors
Journal of Turbomachinery, 2014Co-Authors: Andreas Peters, Zoltán S. Spakovszky, Wesley K. Lord, Becky RoseAbstract:As the propulsor Fan Pressure ratio (FPR) is decreased for improved fuel burn, reduced emissions and noise, the Fan diameter grows and innovative nacelle concepts with short inlets are required to reduce their weight and drag. This paper addresses the uncharted inlet and nacelle design space for low-FPR propulsors where Fan and nacelle are more closely coupled than in current turboFan engines. The paper presents an integrated Fan–nacelle design framework, combining a spline-based inlet design tool with a fast and reliable body-force-based approach for the Fan rotor and stator blade rows to capture the inlet–Fan and Fan–exhaust interactions and flow distortion at the Fan face. The new capability enables parametric studies of characteristic inlet and nacelle design parameters with a short turn-around time. The interaction of the rotor with a region of high streamwise Mach number at the Fan face is identified as the key mechanism limiting the design of short inlets. The local increase in Mach number is due to flow acceleration along the inlet internal surface coupled with a reduction in effective flow area. For a candidate short-inlet design with length over diameter ratio L/D = 0.19, the streamwise Mach number at the Fan face near the shroud increases by up to 0.16 at cruise and by up to 0.36 at off-design conditions relative to a long-inlet propulsor with L/D = 0.5. As a consequence, the rotor locally operates close to choke resulting in Fan efficiency penalties of up to 1.6% at cruise and 3.9% at off-design. For inlets with L/D < 0.25, the benefit from reduced nacelle drag is offset by the reduction in Fan efficiency, resulting in propulsive efficiency penalties. Based on a parametric inlet study, the recommended inlet L/D is suggested to be between 0.25 and 0.4. The performance of a candidate short inlet with L/D = 0.25 was assessed using full-annulus unsteady Reynolds-averaged Navier–Stokes (RANS) simulations at critical design and off-design operating conditions. The candidate design maintains the propulsive efficiency of the baseline case and fuel burn benefits are conjectured due to reductions in nacelle weight and drag compared to an aircraft powered by the baseline propulsor.
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Ultra-Short Nacelles for Low Fan Pressure Ratio Propulsors
Volume 1A: Aircraft Engine; Fans and Blowers, 2014Co-Authors: Andreas Peters, Zoltán S. Spakovszky, Wesley K. Lord, Becky RoseAbstract:As the propulsor Fan Pressure ratio (FPR) is decreased for improved fuel burn, reduced emissions and noise, the Fan diameter grows and innovative nacelle concepts with short inlets are required to reduce their weight and drag. This paper addresses the uncharted inlet and nacelle design space for low-FPR propulsors where Fan and nacelle are more closely coupled than in current turboFan engines. The paper presents an integrated Fan-nacelle design framework, combining a spline-based inlet design tool with a fast and reliable body-force-based approach for the Fan rotor and stator blade rows to capture the inlet-Fan and Fan-exhaust interactions and flow distortion at the Fan face. The new capability enables parametric studies of characteristic inlet and nacelle design parameters with a short turn-around time. The interaction of the rotor with a region of high streamwise Mach number at the Fan face is identified as the key mechanism limiting the design of short inlets. The local increase in Mach number is due to flow acceleration along the inlet internal surface coupled with a reduction in effective flow area. For a candidate short-inlet design with length over diameter ratio L/D = 0.19, the streamwise Mach number at the Fan face near the shroud increases by up to 0.16 at cruise and by up to 0.36 at off-design conditions relative to a long-inlet propulsor with L/D = 0.5. As a consequence, the rotor locally operates close to choke resulting in Fan efficiency penalties of up to 1.6 % at cruise and 3.9 % at off-design. For inlets with L/D < 0.25, the benefit from reduced nacelle drag is offset by the reduction in Fan efficiency, resulting in propulsive efficiency penalties. Based on a parametric inlet study, the recommended inlet L/D is suggested to be between 0.25 and 0.4. The performance of a candidate short inlet with L/D = 0.25 was assessed using full-annulus unsteady RANS simulations at critical design and off-design operating conditions. The candidate design maintains the propulsive efficiency of the baseline case and fuel burn benefits are conjectured due to reductions in nacelle weight and drag compared to an aircraft powered by the baseline propulsor.Copyright © 2014 by ASME
