Browse Topic: Turbofan engines

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Performance Analysis of a High-Speed Tiltrotor Aircraft Featuring VerdeGo Aero's VH-5 Hybrid-Electric Turbofan EngineF-0080-2024-12355/7/2024
In the pursuit of High-Speed Vertical Takeoff and Landing (HSVTOL) platforms, VerdeGo Aero offers its VH-5 hybrid-electric turbofan as the answer to missions requiring high power, vertical lift, and jet-like speeds. To evaluate the possibility of designing a real HSVTOL aircraft around VerdeGo's VH-5 powerplant, this paper investigates the size and expected performance of a militarized spinoff of NASA's Class B, High-Efficiency Civil TiltRotor (HECTR) concept, which has been renamed the VerdeGo Hybrid-Electric Combative TiltRotor, or "VHECTR" for short. Through an in-depth conceptual weight buildup of four commonly proposed tiltrotor architectures, this paper suggests that an entirely new, turbofan-driven propulsion system is needed if modern day HSVTOL demands are to be met. Hence, a separate, yet more conventional "Modified HECTR" tiltrotor configuration is considered to contest the proposed, VH-5 powered VHECTR concept. However, the results of a full-scale aircraft comparison
Roiati, Riccardo, Rice, Tyler, Steinfeldt, Brock, Nitzsche, Jasper, Anderson, Richard
Hydrogen Fueled Aircraft Engines2022-26-11565/26/2022
In the recent years, the climate change has become more devastating, and its continuing use of fossil fuels seems unreasonable as humankind is being pushed into a corner where the need to choose an alternative fuel has become necessary. The two main alternatives currently available are: Electrical propulsion and Hydrogen injected air breathing engines. Electrical propulsion had come far since last 10 years with Li+ ion technology, but the problem with them persists. They provide a low power to weight ratio which reduces the range as well as the load while operating the aircraft. On the other hand, Hydrogen with fuel cells or H2-O2 combustion has a high power to weight ratio but very difficult to handle. So, using hydrogen comes with a lot of difficulties in the present scenario. However. the concept of hydrogen has come a long way since its first use as a Rocket fuel. But this alternate fuel provides many advantages as well as challenges which needs to be overcome to move on its use in
Sri, Ratan, Sivamani, Seralathan
SAE TOMORROW TODAY: Cleaner, Greener & Quieter: Transforming the Future of Flying131619/3/2021
The best airplane can only be designed around the best engine - so says Pratt & Whitney, a Raytheon Technologies Company, where they've been transforming powered flight with an explorer's heart and a perfectionist's grit. Lisa Claveloux, Pratt & Whitney's Senior Director, Group Quality, tells the iconic brand's history, what impacts the pandemic has had on the aerospace industry, and the more sustainable footprint that their GTF engines bring to the skies. These revolutionary geared turbofan engines have already saved more than half a billion gallons of fuel and about five million metric tonnes of CO2, while also slashing aircraft noise footprint by 75%. Claveloux's passion for safety drew her to the work of the SAE ITC Aerospace Engine Supplier Quality (AESQ) strategy group. She discusses the challenges in the market, the gap the SAE AS13100 Standard fills, and why compliance is critical for enabling quality and making our skies safe for everyone.
Hineman, Marcie
Landing Gear Integration into Aircraft Structure in Early Design Stage2019-01-18909/16/2019
The demanded development towards various emission reduction goals set up by several institutions forces the aerospace industry to think about new technologies and alternative aircraft configurations. With these alternative aircraft concepts, the landing gear layout is also affected. Turbofan engines with very high bypass ratios could increase the diameter of the nacelles extensively. In this case, mounting the engines above the wing could be a possible arrangement to avoid an exceedingly long landing gear. Thus, the landing gear could be shortened and eventually mounted at the fuselage instead of the wings. Other technologies such as high aspect ratio wings have an influence on the landing gear integration as well. To assess the difference, especially in weight, between the conventional landing gear configuration and alternative layouts a method is developed based on preliminary structural designs of the different aircraft components, namely landing gear, wing and fuselage. Simplified
Kling, Ulrich, Hornung, Mirko
Aircraft Engine Icing Event Avoidance and MitigationTBMG-347387/1/2019
Innovators at NASA’s Glenn Research Center have developed a new means of avoiding and mitigating icing events for aircraft flying above 14,000 feet, dramatically improving aviation safety and reducing operating costs.
Scaling Evaluation of Ice-Crystal Icing on a Modern Turbofan Engine in PSL Using the COMDES-MELT Code2019-01-19206/10/2019
This paper presents preliminary ice-crystal icing (ICI) altitude scaling evaluation results of a Honeywell Uncertified Research Engine (HURE) that was tested in the NASA Glenn Research Center Propulsion Systems Laboratory (PSL) during January of 2018. This engine geometry features a hidden core design to keep the core less exposed. The engine was fitted with internal video cameras to observe various ice buildup processes at multiple selected locations within the engine core flow path covering the fan stator, the splitter-lip/shroud/strut, and the high pressure compressor (HPC) variable inlet guide vane (IGV) regions. The potential ice accretion risk was pre-determined to occur by using NASA’s in-house 1D Engine Icing Risk assessment code, COMDES-MELT. The code was successful in predicting the risk of ice accretion in adiabatic regions like the fan-stator of the HURE at specific engine operating points. However at several operating points during the test, liquid water was observed
Tsao, Jen-Ching
The Effect of Crosswinds on Icing at Turbofan Engine Inlet2019-01-20246/10/2019
Ice accretion at engine inlet has a dangerous effect on the inlet airflow and shed ice would be ingested into the engine and cause compressor blades damage, and even combustors flame out. In order to analyze the effect of crosswinds on icing at turbofan engine inlet, a complete icing analysis method, which is based on the Messinger model and takes the influence of runback water into consideration, is constructed. The runback water is considered laminar flow and the flow direction is dominated by the bottom flow of air. The supercooled water droplets impingement, ice accretion and runback water characteristics and inlet distortion with and without ice were investigated at crosswinds speed of 15, 20, 25, 30 kt. The variation of local water collection coefficient β is unchanged at crosswind conditions, but the location of the maximum value and non-dimensional impact limits change with the crosswind, which move backward along the outer edge on the windward, and move along the inner edge on
Yang, Qian, Guo, Zhiqiang, Zheng, Mei, Dong, Wei
Wind Tunnel Measurements of Simulated Glaciated Cloud Conditions to Evaluate Newly Developed 2D Imaging Probes2019-01-19816/10/2019
Instrumentation that has been used for characterization of mixed-phase and glaciated conditions in the past, like the OAP probes, are subject to errors caused by variations in diffraction on the images away from the object plane and by the discrete nature of their particle detection and sizing. Correction methods are necessary to consider their measurements adequate for high ice water content (IWC) environments judged to represent a significant safety hazard to propellers and turbofan engine operability and performance. For this reason, within the frame of EU FP7 HAIC project, instrumentation characterization and validation is considered a major element need for successful execution of flight tests campaigns. Clearly, instrumentation must be sufficiently reliable to assess the reproducibility of artificial clouds with high ice water content generated in icing tunnels. Instruments are required to measure these conditions with a sufficient level of accuracy for the purposes of the
Esposito, Biagio M., Bachalo, William D., Leroy, Delphine, Schwarzenboeck, Alfons, Jurkat, Tina, Voigt, Christiane, Bansmer, Stephan
Microwave Technique for Liquid Water Detection in Icing Applications2019-01-19306/10/2019
The partial melting of ingested ice crystals can lead to ice accretion in aircraft compressors, but accurately measuring the relatively small fraction of liquid water content in such flows is challenging. Probe-based methods for detecting liquid water content are not suitable for deployment within turbofan engines, and thus alternatives are sought. Recent research has described approaches based on passive microwave sensing. We present here an approach based on active microwave transmission and reflection, employing a vector network analyzer. Utilization of both transmission and reflection provides additional data over and above emission or transmission only, and permits a more controllable environment than passive sensing approaches. The paper specifically addresses the question of whether such an approach is viable within the context of representative icing wind tunnel and engine flow conditions. A quasi-thermal equilibrium approach is presented herein to estimate the melting ratio
Leis, John, Buttsworth, David, Saeed, Ramiz, Saleh, Khalid, McGilvray, Matthew, Gillespie, David
Semi-Empirical Modelling of Erosion Phenomena for Ice Crystal Icing Numerical Simulation2019-01-19676/10/2019
The aim of this work is to develop a semi-empirical model for erosion phenomena under ice crystal condition, which is one of the major phenomena for ice crystal accretion. Such a model would be able to calculate the erosion rate caused by impinging ice crystals on accreted ice layer. This model is based on Finnie [1] and Bitter [2] [3] solid/solid collision theory which assumes that metal erosion due to sand impingement is driven by two phenomena: cutting wear and deformation wear. These two phenomena are strongly dependent on the particle density, velocity and shape, as well as on the surface physical properties such as Young modulus, Poisson ratio, surface yield strength and hardness. Moreover, cutting wear is mostly driven by tangential velocity and is more effective for ductile eroded body, whereas deformation wear is driven by normal velocity and is more effective for brittle eroded body. Several researchers based their erosion modelling on these two phenomena such as Hutchings et
Charton, Virgile, Trontin, Pierre, Aouizerate, Gilles, Villedieu, Philippe
Design of Composite Materials for Improved Loss-of-Lubrication Survivability of Hybrid Rotorcraft GearsF-0075-2019-146855/13/2019
Hybrid gears featuring steel teeth mated to a composite body provide the potential for significant weight savings in aerospace applications such as rotorcraft and geared turbofan engines. For hybrid gears to be viable for use in these applications, they must not degrade mechanical performance or thermal characteristics, particularly under loss-of- lubrication operation. The heat generated by loss-of-lubrication operation may be especially problematic for the fiber- reinforced polymer composite materials used in hybrid steel-composite gear prototypes. Initial hybrid gear design and testing is described in the literature, but no prior studies have investigated optimization of the composite material for thermal performance. In the study presented herein, conductive fibers and high-temperature polymers are introduced to make a composite material better suited to high-temperature and loss-of-lubrication. Channel-flow resin transfer molding was used to fabricate composites with a variety of
Waller, Matthew, Koudela, Kevin, McIntyre, Sean
Novel Turboelectric Aircraft DesignTBMG-288615/1/2018
NASA Langley Research Center has developed a novel aircraft design that can carry 150+ passengers over a range of 3,500 nautical miles. Key features include a turboelectric propulsion system, twin underwing turbofans, and a rear-fuselage, electrically driven, boundary layer ingesting fan. The design is developed for single-aisle-class aircraft (the largest commercial transport class in the world) to significantly reduce fuel burn compared to current aircraft.
Variable Bypass Turbofan EngineTBMG-288775/1/2018
Many aircraft need to operate efficiently at more than one flight regime; for example, certain airframes are expected to perform in relatively high-speed cruise modes, as well as slower loitering scenarios. Unfortunately, an engine operates most efficiently when the exit velocity closely matches the speed of the airframe. As a result, designing an engine that is suitable for multiple roles yields an engine that only performs moderately well in each of those operating conditions.
Software Helps Optimize World’s Largest All-Composite AircraftTBMG-2800812/1/2017
Collier Research Corp. Newport News, VA
ASTM-D7684-11 Compliant Computer Aided Interactive Wear Debris Particle Analysis for On-Site Condition Monitoring, Diagnostics and Prognostics2017-01-21249/19/2017
Within the aviation industry analysis of wear debris particles recovered from magnetic plugs and lubricating fluids is an essential condition monitoring tool. However, in large organisations, high staff turnover in remote work environments often leaves dangerous gaps in on-site support and background knowledge. The current work develops interactive software for wear debris particle classification, root cause diagnosis and serviceability prognostics. During the research several hundred wear debris particle images were collected, analysed and classified by a number of experts. At each stage of the analysis the experts were questioned about the knowledge and experience used to make their diagnoses and prognoses. The end result is an extensive knowledge base representing the combined expertise of a number of highly trained engineers, each with decades of hands-on experience. Access to this knowledge base is provided at each stage of interaction with the software, as automatically generated
Leavers, Violet
Turbofan Engine Acoustic Liner Design and Analysis ToolsTBMG-268665/1/2017
NASA Langley Research Center has developed two tools for turbofan engine acoustic liner design and analysis. The first is a statistical approach for broadband liner design and assessment; the second is graphical software to design and analyze resonant channels in acoustic liners.
Uncertainty of In-Flight Thrust DeterminationAIR1678B (Current)10/22/2016
This document defines and illustrates the process for determination of uncertainty of turbofan and turbojet engine in-flight thrust and other measured in-flight performance parameters. The reasons for requiring this information, as specified in the E-33 Charter, are: determination of high confidence aircraft drag; problem rectification if performance is low; interpolation of measured thrust and aircraft drag over a range of flight conditions by validation and development of high confidence analytical methods; establishment of a baseline for future engine modifications. This document describes systematic and random measurement uncertainties and methods for propagating the uncertainties to the more complicated parameter, in-flight thrust. Methods for combining the uncertainties to obtain given confidence levels are also addressed. Although the primary focus of the document is in-flight thrust, the statistical methods described are applicable to any measurement process. The E-33 Committee
E-33 In Flight Propulsion Measurement Committee
Numerical Investigations on a Tunable Helmholtz Resonator: Integration of a Passive Polymer Membrane in a Helmholtz Resonator2016-01-18426/15/2016
A Helmholtz resonator is a passive acoustic resonator used to control a single frequency resulting from the cavity volume and the resonator neck size. The main purpose of work in progress is to propose to investigate numerically some strategies allowing real-time tunability of the Helmholtz resonator in order to provide a wider bandwidth and hence enhance noise attenuation. Two concepts will be developed, both based on the use of electroactive polymer (EAP) membranes. These materials exhibit a change of shape when stimulated by an electric field. The first concept consists in replacing the resonator rigid back plate by an EAP material membrane, while on the second one, the membrane is located in front of the resonator. Numerical investigations are performed using several kinds of a passive EAPs material membranes in order to determine the practical potential of these concepts. Significant enhancements of the transmission loss and/or the absorption properties could be obtained in the
Abbad, Ahmed
Cantera Integration with T-MATSTBMG-240993/1/2016
The Toolbox for the Modeling and Analysis of Thermodynamic Systems (TMATS) software package is a library of building blocks that can be assembled to represent any thermodynamic system in the Simulink® (MathWorks, Inc.) environment. These elements, along with a Newton Raphson solver (also provided as part of the T-MATS package), enable users to create models of a wide variety of systems. The updated version of T-MATS (v1.1.1) includes the integration of Cantera, an open source thermodynamic simulation tool. T-MATS was initially described in detail in LEW-19165-1, "", Software Tech Briefs (September 2014), p. 11.
Automated ATM System Enabling 4DT-Based Operations2015-01-25399/15/2015
As part of the current initiatives aimed at enhancing safety, efficiency and environmental sustainability of aviation, a significant improvement in the efficiency of aircraft operations is currently pursued. Innovative Communication, Navigation, Surveillance and Air Traffic Management (CNS/ATM) technologies and operational concepts are being developed to achieve the ambitious goals for efficiency and environmental sustainability set by national and international aviation organizations. These technological and operational innovations will be ultimately enabled by the introduction of novel CNS/ATM and Avionics (CNS+A) systems, featuring higher levels of automation. A core feature of such systems consists in the real-time multi-objective optimization of flight trajectories, incorporating all the operational, economic and environmental aspects of the aircraft mission. This article describes the conceptual design of an innovative ground-based Air Traffic Management (ATM) system featuring
Gardi, Alessandro, Sabatini, Roberto, Ramasamy, Subramanian, Marino, Matthew, Kistan, Trevor
Characterization of the Ultrafine and Black Carbon Emissions from Different Aviation Alternative Fuels2015-01-25629/15/2015
This study reports gaseous and particle (ultrafine and black carbon (BC)) emissions from a turbofan engine core on standard Jet A-1 and three alternative fuels, including 100% hydrothermolysis synthetic kerosene with aromatics (CH-SKA), 50% Hydro-processed Esters and Fatty Acid paraffinic kerosene (HEFA-SPK), and 100% Fischer Tropsch (FT-SPK). Gaseous emissions from this engine for various fuels were similar but significant differences in particle emissions were observed. During the idle condition, it was observed that the non-refractory mass fraction in the emitted particles were higher than during higher engine load condition. This observation is consistent for all test fuels. The 100% CH-SKA fuel was found to have noticeable reductions in BC emissions when compared to Jet A-1 by 28-38% by different BC instruments (and 7% in refractory particle number (PN) emissions) at take-off condition. BC emissions from this fuel were lower than from Jet A-1 by 45-50% (and 25-26% in refractory PN
Chan, Tak W., Chishty, Wajid, Davison, Craig, Buote, David
Ice Crystal Ingestion in a Turbofan Engine2015-01-21466/15/2015
A through-flow based Monte Carlo particle trajectory simulation is used to calculate the ice crystal paths in the low pressure compressor of a high bypass ratio turbofan engine. The simulation includes a statistical ice particle breakup model due to impact on the engine surfaces. Stage-by-stage ice water content, particle size and particle velocity distributions are generated at multiple flight conditions and engine power conditions. The majority of the ice particle breakup occurs in the fan and first LPC stage. The local ice water content (IWC) within LPC is much higher than the ambient conditions due to scoop effects, centrifuging and flow-path curvature. Also the ice particles approach the stators at lower incidence angles than the air flow. The simulation results prompt the need to revisit the approach for properly setting up boundary conditions for component or cascade testing.
Feulner, Matthew, Liao, Shengfang, Rose, Becky, Liu, Xuejun
Computational Method for Ice Crystal Trajectories in a Turbofan Compressor2015-01-21396/15/2015
In this study the characteristics of ice crystals on their trajectory in a single stage of a turbofan engine compressor are determined. The particle trajectories are calculated with a Lagrangian method employing a classical fourth-order Runge-Kutta time integration scheme. The air flow field is provided as input and is a steady flow field solution governed by the Euler equations. The single compressor stage is represented using a cascaded grid. The grid consists of three parts of which the first and the last part are stator parts and the centre part is a rotor. Each particle is modelled as a non-rotating rigid sphere. The remaining model does allow the exchange of heat and mass to and from the particle resulting in a mass, temperature and phase change of the particle. The phase change is based on a perfectly concentric ice core-water film model and it is assumed that the particle is at uniform temperature. The results for the collection efficiency, particle temperature and amount of
Grift, E.J., Norde, E., Van der Weide, E.T.A., Hoeijmakers, H.W.M.
Performance Modeling of Honeywell Turbofan Engine Tested with Ice Crystal Ingestion in the NASA Propulsion System Laboratory2015-01-21336/15/2015
The Propulsion Systems Laboratory (PSL) altitude test facility at NASA Glenn Research Center, has been used to test a full scale Honeywell turbofan engine at simulated altitude operating conditions. The PSL has spray bars to create a continuous cloud of fully glaciated ice crystals. The tests successfully duplicated the icing events that were experienced by the Honeywell engine (ALF502R-5) during flight through ice crystal clouds. After the ice cloud was turned on key engine performance parameters such as the fan speed, air flow rate, fuel flow rate, and compressor exit pressure and temperature responded immediately to the ingestion of the ice crystals. For some of the test points, these performance parameters remained unchanged from the initial response to the ice crystals, while during other test points the engine performance began to deteriorate to the point where an uncommanded loss of thrust control (engine rollback) was judged by the test engineers to have been imminent. The data
Veres, Joseph P., Jones, Scott M., Jorgenson, Philip C. E.
Development of a Coupled Air and Particle Thermal Model for Engine Icing Test Facilities2015-01-21556/15/2015
This paper describes a numerical model that simulates the thermal interaction between ice particles, water droplets, and the flowing air applicable during icing wind tunnel tests where there is significant phase-change of the cloud. It has been previously observed that test conditions, most notably temperature and humidity, change when the icing cloud is activated. It is hypothesized that the ice particles and water droplets thermally interact with the flowing air causing the air temperature and humidity to change by the time it reaches the test section. Unlike previous models where the air and particles are uncoupled, this model attempts to explain the observed changes in test conditions by coupling the conservation of mass and energy equations. The model is compared to measurements taken during wind tunnel tests simulating ice-crystal and mixed-phase icing that relate to ice accretions within turbofan engines. The model simulates trends that were experimentally observed, but does not
Bartkus, Tadas P., Struk, Peter, Tsao, Jen-Ching
Ice Crystal Icing Engine Testing in the NASA Glenn Research Center's Propulsion Systems Laboratory: Altitude Investigation2015-01-21566/15/2015
The National Aeronautics and Space Administration (NASA) conducted a full scale ice crystal icing turbofan engine test using an obsolete Allied Signal ALF502-R5 engine in the Propulsion Systems Laboratory (PSL) at NASA Glenn Research Center. The test article used was the exact engine that experienced a loss of power event after the ingestion of ice crystals while operating at high altitude during a 1997 Honeywell flight test campaign investigating the turbofan engine ice crystal icing phenomena. The test plan included test points conducted at the known flight test campaign field event pressure altitude and at various pressure altitudes ranging from low to high throughout the engine operating envelope. The test article experienced a loss of power event at each of the altitudes tested. For each pressure altitude test point conducted the ambient static temperature was predicted using a NASA engine icing risk computer model for the given ambient static pressure while maintaining the engine
Oliver, Michael
Tool for Turbine Engine Closed-loop Transient Analysis (TTECTrA)TBMG-222056/1/2015
The current steady-state performance-based system studies are not adequate to evaluate certain advanced technologies for the challenges associated with meeting the transient performance requirements without better definition and control of component operating margins. Additional dynamic analyses would require more detailed, physics-based, component-level models and controllers in order to better identify dynamic issues that may arise during operation of the engine. The additional complexity in these models increases the effort necessary throughout the design processes, including the system-analysis step. The solution would be a physics-based engine model with full envelope controller. C-MAPSS and C-MAPSS40k are examples of engine models with full envelope controllers, but because they are designed to model a specific engine, they are not good candidates for systems analysis.
Passive Destructive Interference Acoustic Liner for a Turbofan Engine Using Additive ManufacturingTBMG-219995/1/2015
This technology exploits the capabilities of additive manufacturing to attenuate the fan noise within the inlet or aft duct of a turbofan engine. The approach may be expanded to include auxiliary power units, environmental control systems, or other cooling systems requiring noise attenuation.
Transient Engine Emulation within a Laboratory Testbed for Aircraft Power Systems2014-01-21709/16/2014
This paper presents the details of an engine emulation system utilized within a Hardware-in-the-Loop (HIL) test environment for aircraft power systems. The paper focuses on the software and hardware interfaces that enable the coupling of the engine model and the generator hardware. In particular, the rotor dynamics model that provides the critical link between the modeled dynamics of the engine and the measured dynamics of the generator is described in detail. Careful consideration for the measured torque is included since the measurement contains inertial effects as well as torsional resonances. In addition, the rotor model is equipped with the ability to apply power and speed scaling between the engine and generator. This scaling approach provides significant flexibility that can be useful when hardware resources are limited such that a direct engine-generator match is not possible or when one wants to evaluate turboshaft engine dynamics for a variety of applications and power levels
Bash, Michelle, Boyd, Michael, Miller, Chad
HTF7000 Engine Design, Development and Uses2013-01-22289/17/2013
Honeywell has developed a unique turbofan engine for application to the super mid-size business aviation market, the HTF7000. This paper will describe the design of this engine including aeromechanical design of its components. The unique design features of this engine will be described along with the technology growth path to keep the engine current. This paper will also describe several features which have been developed for this engine in response to new regulatory requirements. Some aspects of the engine to aircraft integration will also be described.
Winstanley, David K.
Distribution of Power13AERD0603_026/3/2013
When designing the electrical distribution system for a turboelectric architecture, it is imperative to select technologies that will provide the highest efficiency and stability for the propulsion system. Turboelectric propulsion is a revolutionary system in which the propulsor (fan) is not connected to the turbine through a mechanical connection; thus, both components can be set at their individual optimum speeds. Also, turboelectric propulsion makes use of distributed fans, using several small fans in place of the traditional large propulsors on the wings or sides of the fuselage. Distributed fans are usually placed on the top side of the fuselage of a blended wing body aircraft to take advantage of boundary layer ingestion that increases fan performance. The smaller fans can run at faster speeds than their larger counterpart in a turbofan engine.
Integrated Engine/Thermal Architecture Model Interface Development2011-01-258510/18/2011
Integrated system-level analysis capability is critical to the design and optimization of aircraft thermal, power, propulsion, and vehicle systems. Thermal management challenges of modern aircraft include increased heat loads from components such as avionics and more-electric accessories. In addition, on-going turbine engine development efforts are leading to more fuel efficient engines which impact the traditionally-preferred heat sink - engine fuel flow. These conditions drive the need to develop new and innovative ways to manage thermal loads. Simulation provides researchers the ability to investigate alternative thermal architectures and perform system-level trade studies. Modeling the feedback between thermal and engine models ensures more accurate thermal boundary conditions for engine air and fuel heat sinks, as well as consideration of thermal architecture impacts on engine performance. Interface development is an important aspect of the system modeling process, and this paper
Puterbaugh, Rebekah L., Brown, Jeffrey, Battelle, Ryan T.
Acoustic Liner for Turbomachinery ApplicationsTBMG-84919/1/2010
The purpose of this innovation is to reduce aircraft noise in the communities surrounding airports by significantly attenuating the noise generated by the turbomachinery, and enhancing safety by providing a containment barrier for a blade failure. Acoustic liners are used in today’s turbofan engines to reduce noise. The amount of noise reduction from an acoustic liner is a function of the treatment area, the liner design, and the material properties, and limited by the constraints of the nacelle or casement design. It is desirable to increase the effective area of the acoustic treatment to increase noise suppression. Modern turbofan engines use “wide-chord” rotor blades, which means there is considerable treatment area available over the rotor tip.
Taking measures of the machineAEROAPR08_034/1/2008
New requirements and technologies advance the art of test and sensing. Few sensor and instrumentation environments are more challenging than those found inside a jet engine. With temperatures up to 1200°F in the hot section, the climate is particularly hostile to just about anything that an engineer can design. “Measurements inside an engine are in a number of ways limited by the operational requirements of the engine,” said Gary Hunter, Intelligence Systems Hardware Lead in the Sensors and Electronics branch at NASA Glenn Research Center (GRC). “It is hot and gases flow at high velocity rates. If you wish something to be in the engine, it needs to survive the harsh environment, and not a lot of things can survive there.”
Rosenberg, Barry
Long Range Aircraft, an Ideal Case for Fuel Cell Power2007-01-295711/28/2007
This paper shows that the analysis of factors such as costs, weights, fuel distribution logistics, etc. indicates that the replacement of internal combustion engines (ICE) by fuel cell/electric motor (FC/EM) systems, can be more attractive to aeronautical than to automotive applications. For long range airplanes especially, where the fuel represents an important fraction of the vehicle weight, the penalties from that replacement by a heavier system, can be overcome by the fuel weight reductions resulting from the higher fuel cell efficiencies. The necessity of FC/EM powered airplanes is also discussed in view of the eventual climate effects the air traffic may have, due to the injection of carbon dioxide and water vapor into the high troposphere. Some of the weight and aerodynamic issues posed by a FC/EM medium sized long range transport airplane preliminary design are discussed, and a non conventional aircraft configuration is proposed to be used in order to partially compensate the
Galvão, Francisco Leme
System Would Detect Foreign-Object Damage in Turbofan EngineTBMG-TB-0010601/29/2007
Vibration-sensor and gas-path-analysis data would be fused. A proposed data-fusion system, to be implemented mostly in software, would further process the digitized and preprocessed outputs of sensors in a turbofan engine to detect foreign-object damage (FOD) [more precisely, damage caused by impingement of such foreign objects as birds, pieces of ice, and runway debris]. The proposed system could help a flight crew to decide what, if any, response is necessary to complete a flight safely, and could aid mechanics in deciding what post-flight maintenance action might be needed.
Breaking records via fuel managementAEROMAY06_035/1/2006
Onboard sensors reported lower-than-expected fuel-tank readings not far into the around-the-world flight of the GlobalFlyer, jeopardizing the entire mission. In March 2005, the Virgin Atlantic turbofan-powered GlobalFlyer flew around the world nonstop, unrefueled, in 67 hours and one minute. Aerodynamics was key to GlobalFlyer's success; its configuration was optimized for range and fuel efficiency. At takeoff, the aircraft was approximately 83% fuel by weight. Getting the fuel to where it was needed, while maintaining balance and stability in flight, required constant supervision and monitoring. Scaled Composites, which also designed and launched SpaceShipOne, built the GlobalFlyer. The aircraft consisted of three bodies attached to a 114-ft wing measuring more than half the wingspan of a Boeing 747. Twin “booms” on either side of the central fuselage each carried almost 5500 lb of fuel.
System Would Detect Foreign-Object Damage in Turbofan EngineTBMG-10601/1/2006
A proposed data-fusion system, to be implemented mostly in software, would further process the digitized and preprocessed outputs of sensors in a turbofan engine to detect foreign-object damage (FOD) [more precisely, damage caused by impingement of such foreign objects as birds, pieces of ice, and runway debris]. The proposed system could help a flight crew to decide what, if any, response is necessary to complete a flight safely, and could aid mechanics in deciding what post-flight maintenance action might be needed.
Aerospace Engineering 2004-07-01AEROJUL047/1/2004
More-electric small turbofan engines The aerospace industry demands continuous improvement of propulsion engines as well as timely response to the new and changing requirements for them. Zero-emissions aircraft Researchers explore the potential application of alternative fuels and propulsion systems for aircraft that include a business jet and single-engine propeller aircraft. Integration releases the reins Cessna's new Citation Mustang launches the company into a new market for business jets, helped by the latest PLM solutions from IBM. Military: general A military flight-control system proposed for use in general aviation uses inverse control to decouple the flight controls and to modify the handling qualities of the aircraft, while employing articficial neural networks to compensate for any modeling errors.
Integration releases the reinsAEROJUL04_037/1/2004
Cessna's new Citation Mustang launches the company into a new market for business jets, helped by the latest PLM solutions from IBM. At the National Business Aviation Association convention in September 2002, Cessna unveiled the Citation Mustang, an all-new, entry-level business jet. With two turbofan engines and space for two pilots and four passengers, the new airplane will have a cruising speed of 340 knot, a maximum operating altitude of 41,000 ft, and a takeoff distance of 3120 ft at MTOW (maximum take-off weight). The Mustang will have a VFR (visual flight rules) range of 1300 nmi. With more than 200 orders already taken, approximately half U.S. and half international customers, the assembly plant in Independence, KS, is expected to more than double its workforce by the time the aircraft is in full production. Certification is expected in mid-2006, with first customer deliveries in the fourth quarter of 2006.
Alexander, David
Program Predicts Broadband Noise From a Turbofan EngineTBMG-17521/1/2004
Broadband Fan Noise Prediction System (BFaNS) is a computer program that, as its name indicates, predicts the broadband noise generated by the fan stage of a turbofan engine. This noise is the sum of (1) turbulent- inflow noise, which is caused by turbulence impinging on leading edges of the fan and the fan exit guide vane and (2) self noise, which is caused by turbulence convecting past the corresponding trailing edges. The user provides input data on the fan-blade, vane, and flow-path geometries and on the mean and turbulent components of the flow field. BFaNS then calculates the turbulent-inflow noise by use of D. B. Hanson's theory, which relates sound power to the inflow turbulence characteristics and the cascade geometry. Hanson's program, BBCASCADE, is incorporated into BFaNS, wherein it is applied to the rotor and stator in a stripwise manner. The spectra of upstream and downstream sound powers radiated by each strip are summed to obtain the total upstream and downstream sound
Bombardier CRJ900 and CRJ700AEROJUN02_046/1/2002
Bombardier hits 70- to 100-seat regional market running. Already creating a position for itself in the 50- to 100-seat regional jet market, Bombardier's CRJ200 70-seat derivative, the CRJ700, has recently entered service with its North American launch customer American Eagle. The company is also continuing with development of its 86-seat CRJ900, which is scheduled for certification later this year and first delivery early 2003. Officially launched January 1997, the CRJ700 was developed to meet the demand for larger aircraft with superior operating economies on regional airline jet routes. With an overall length of 106 ft, 8 in. and a wingspan of 76 ft, 3 in., the aircraft is 19 ft longer and has a wingspan 7 ft greater than the 50-seat CRJ200. To date, the CRJ700 has received certification from Transport Canada, European Joint Aviation Authorities, and the U.S. Federal Aviation Administration. First customer delivery to Brit Air of Morlaix, France, took place in January 2001, with the
Aerospace Engineering 2001-11-01AERONOV0111/1/2001
Safeguarding aircraft systems How several systems suppliers, airframers, and researchers have approached the need for increased system safeguards and protection against lightning strikes. One last look back A review of the technology news, discussions, and announcements from the first Aerospace Congress & Exhibition held September 10-13 in Seattle, WA. Powering unmanned aircraft Pratt & Whitney Canada is developing and testing a commercial turbofan engine derivative for high-altitude unmanned air vehicle applications. 737-800 winglet integration A joint venture between Boeing and Aviation Partners Inc. is involved in developing a performance improvement for in-service aircraft.
Optimal and Near-Optimal Take-off Maneuvers in the Presence of Windshear2000-01-559310/10/2000
This paper is concerned with the development of short-range forward-look guidance strategies for take-off maneuvers in the presence of windshear, with reference to flight in the vertical and horizontal plane. In addition to the horizontal shear, the presence of a downdraft is assumed. First, two open-loop optimal escape strategies are considered, viz. a performance maintaining strategy and a survival strategy, where it is assumed that the windshear is detected in an early stage of the encounter. Next, two closed-loop guidance strategies featuring short-range forward-look detection, which closely approximate the open-loop optimal solutions, are developed. Numerical results show that lateral maneuvering, in which an aircraft is turned away from the microburst, improves the flight performance significantly in both optimal escape strategies. The simulation results demonstrate that the employed closed-loop guidance strategies are able to closely approximate the open-loop optimal
Elferink, K., Visser, H.G.
Software Predicts Noise From Rotor-Wake/Stator InteractionsTBMG-696310/1/2000
V072 is a computer program that predicts the noise generated by the interaction between the rotor-blade wake (fan wake) and the stator vanes of a turbofan engine. The program is a combination of subroutines from prior NASA programs, with many added features.
Development of Aircraft-Specific Accident Investigation Reference Data Handbooks2000-01-21034/11/2000
This paper discusses the background, development, features and utility of aircraft-specific mishap investigation reference materials.
Gwynne, Donald G.
Passive Aircraft Anti Icing System Using Waste Heat9815427/13/1998
A passive anti icing system for the engine cowl of the Global Hawk UAV was designed and evaluated under a NASA Phase I SBIR Program. The system utilizes five Loop Heat Pipes to remove 3.8 kW of waste heat from the hydraulic system and deliver it to the engine inlet during icing conditions. During non-icing conditions the heat is bypassed to relief valves on the fuel ullage tank to maintain their temperature above freezing. The system masses 18.5 kg and replaces some 15 lbs of existing equipment. A Phase II program to integrate the system aboard the aircraft is underway with the goal of starting flight tests in early 1999.
Phillips, A. L. (Fred), Gernert, Nelson J.
Recommended Values of Rain and Hail Concentrations to be Considered in the Design of Turbine Engines96559610/1/1996
Extreme rain and hail conditions have caused engine rundowns during commercial airplane flights. In some cases, rain and hail conditions have caused all of the engines on the airplane to rundown simultaneously. This paper presents an analysis that quantifies the rain and hail threat in terms of the probability of encountering a storm of a given intensity for a given period of time. This analysis was used to establish recommended rain and hail concentration levels for design and certification of turbine engines.
Moravec, Bradford A., Patnoe, Michael W.
The Development and Application of Aircraft Radar Cross Section Prediction Methodology96553910/1/1996
In the last twenty years, radar cross section (RCS) reduction has emerged as an important and achievable way to improve the survivability of military aircraft. Specifically, the first manned aircraft to achieve a tactically significant reduction in RCS was the Lockheed Have Blue technology demonstrator, which was designed starting in 1975 and first flew in 1977. This was followed by a true military aircraft, the F-117 A, which became operational in 1983. Several very low observable (VLO) aircraft have been designed since then. All of them benefit from significant advances in the ability to predict and improve the RCS of an aircraft in its early design stages. The present paper describes these advances and their impact on aircraft design, using examples of reduced RCS aircraft designed before and after the techniques were evolved.
Aronstein, David C.
Preliminary Sizing of a Supersonic Commercial Transport Between Mach 2.0 and 2.496558910/1/1996
To review specifications of a next-generation supersonic commercial transport (SCT), conceptual design is performed. The study covers the cruise speed between Mach 2.0 and 2.4, and the range between 4,000 nmi and 6,000 nmi with the number of seats fixed to 300. Engines for Mach 2.0, 2.2 and 2.4 are conceptually designed and the data are applied to Japan Aircraft Development Corporation (JADC)'s SCT sizing and performance prediction tool (“CAD”). The maximum take off weights (MTOW) are surveyed to find the best combination of cruise speed and range.
Takasu, Toru, Maekawa, Shoji, Ugai, Takashi, Mizuno, Hiroshi
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