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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
NASA NTRS1997

TURBO-AE: An Aeroelastic Code for Propulsion Applications

NASA's Advanced Subsonic Technology (AST) program is developing new technologies to increase the fuel efficiency of commercial aircraft engines, improve the safety of engine operation, and reduce engine emissions and noise. With the development of new designs for ducted fans, compressors, and turbines to achieve these goals, a basic aeroelastic requirement is that there should be no flutter or high resonant blade stresses in the operating regime. To verify the aeroelastic soundness of these designs, we need an accurate prediction and analysis code. Such a two-dimensional viscous propulsion aeroelastic code, named TURBO-AE, is being developed at the NASA Lewis Research Center. The TURBO-AE aeroelastic code is based on a three-dimensional unsteady aerodynamic Euler/Navier-Stokes turbomachinery code TURBO, developed under a grant from NASA Lewis. TURBO-AE can model viscous flow effects that play an important role in certain aeroelastic problems, such as flutter with flow separation (or stall flutter) and flutter in the presence of shock and boundary-layer interaction. The structural dynamics representation of the blade in the TURBO-AE code is based on a normal mode representation. A finite element analysis code, such as NASTRAN, is used to calculate in-vacuum vibration modes and the associated natural frequency. A work-per-cycle approach is used to determine aeroelastic (flutter) stability. With this approach, the motion of the blade is prescribed to be a harmonic vibration in a specified in vacuum normal mode. The aerodynamic forces acting on the vibrating blade and the work done by these forces on the vibrating blade during a cycle of vibration are calculated. If positive work is being done on the blade by the aerodynamic forces, the blade is dynamically unstable, since it will extract energy from the flow, leading to an increase in the amplitude of the blade's oscillation. Initial calculations have been done for a configuration representative of the Energy Efficient Engine fan rotor. The accompanying figure shows the work-per-cycle after each cycle of vibration. It can be seen that the work-per-cycle does not vary much after the fourth cycle. The negative sign of the converged work-per-cycle shows that the fan blade is dynamically stable and will not flutter. TURBO-AE will provide a useful aeroelastic prediction/analysis capability for engine manufacturers. It will reduce design cycle times by allowing new blade designs to be verified for aeroelastic soundness before blades are built and tested. With this prediction capability, it will be possible to build thinner, lighter, and faster rotating blades without encountering aeroelastic problems like stall flutter and high-cycle fatigue due to forced vibrations.

Bakhle, Milind A.↗
NASA NTRS1999

Flutter Version of Propulsion Aeroelasticity Code Completed

NASA s Advanced Subsonic Technology (AST) Program seeks to develop new technologies to increase the fuel efficiency of commercial aircraft engines, improve the safety of engine operation, and reduce emissions and engine noise. For new designs of ducted fans, compressors, and turbines to achieve these goals, a basic aeroelastic requirement is that there should be no flutter or high resonant blade stresses in the operating regime. For verifying the aeroelastic soundness of the design, an accurate prediction/analysis code is required. Such a three-dimensional viscous propulsion aeroelastic code, named TURBO-AE, is being developed at the NASA Lewis Research Center. The development and verification of the flutter version of the TURBO-AE code (version 4) has been completed. Validation of the code is partially complete.

Bakhle, Milind A.↗
NASA NTRS2005

Wake Vortex Wingtip-Turbine Powered Circulation Control High-Lift System

NASA s Vehicle Systems Program is investing in aeronautics technology development across six vehicle sectors, in order to improve future air travel. These vehicle sectors include subsonic commercial transports, supersonic vehicles, Uninhabited Aerial Vehicles (UAVs), Extreme Short Takeoff and Landing (ESTOL) vehicles, Rotorcraft, and Personal Air Vehicles (PAVs). While the subsonic transport is firmly established in U.S. markets, the other vehicle sectors have not developed a sufficient technology or regulatory state to permit widespread, practical use. The PAV sector has legacy products in the General Aviation (GA) market, but currently only accounts for negligible revenue miles, sales, or market share of personal travel. In order for PAV s to ever capture a significant market, these small aircraft require technologies that permit them to be less costly, environmentally acceptable, safer, easier to operate, more efficient, and less dependent on large support infrastructures.

Moore, Mark D.↗
NASA NTRS1995

Space Window

The National Aeronautics and Space Administration has three field centers in California. Ames Research Center specializes in aeronautics research and information technology, with activities in astrobiology and space science. Dryden Flight Research Center conducts aircraft flight operations, and is a Space Shuttle landing site. Jet Propulsion Laboratory specializes in planetary exploration.

NASA Ames Research Center Dryden Flight Research C↗
NASA NTRS1996

Tropospheric Emission Spectrometer and Airborne Emission Spectrometer

The Tropospheric Emission Spectrometer (TES) is an instrument being developed for the NASA Earth Observing System Chemistry Platform. TES will measure the distribution of ozone and its precursors in the lower atmosphere. The Airborne Emission Spectrometer (AES) is an aircraft precursor to TES. Applicable descriptions are given of instrument design, technology challenges, implementation and operations for both.

TES AES Ozone Spectrometer Earth Observation↗
NASA NTRS2006

Preliminary Sizing of 120-Passenger Advanced Civil Rotorcraft Concepts

The results of a preliminary sizing study of advanced civil rotorcraft concepts that are capable of carrying 120 passengers over a range of 1,200 nautical miles are presented. The cruise altitude of these rotorcraft is 30,000 ft and the cruise velocity is 350 knots. The mission requires a hover capability, creating a runway independent solution, which might aid in reducing strain on the existing airport infrastructure. Concepts studied are a tiltrotor, a tandem rotor compound, and an advancing blade concept. The first objective of the study is to determine the relative merits of these designs in terms of mission gross weight, engine size, fuel weight, aircraft purchase price, and direct operating cost. The second objective is to identify the enabling technology for these advanced heavy lift civil rotorcraft.

vanAken, Johannes M.↗
NASA NTRS2012

Initial Investigations of Controller Tools and Procedures for Schedule-Based Arrival Operations with Mixed Flight-Deck Interval Management Equipage

NASA's Air Traffic Management Demonstration-1 (ATD-1) is a multi-year effort to demonstrate high-throughput, fuel-efficient arrivals at a major U.S. airport using NASA-developed scheduling automation, controller decision-support tools, and ADS-B-enabled Flight-Deck Interval Management (FIM) avionics. First-year accomplishments include the development of a concept of operations for managing scheduled arrivals flying Optimized Profile Descents with equipped aircraft conducting FIM operations, and the integration of laboratory prototypes of the core ATD-1 technologies. Following each integration phase, a human-in-the-loop simulation was conducted to evaluate and refine controller tools, procedures, and clearance phraseology. From a ground-side perspective, the results indicate the concept is viable and the operations are safe and acceptable. Additional training is required for smooth operations that yield notable benefits, particularly in the areas of FIM operations and clearance phraseology.

Callantine, Todd J.↗
NASA NTRS1984

Design of advanced technology maneuvering aircraft models for the National Transonic Facility

The need for a large High-Reynolds-Number Transonic Wind Tunnel which will provide a tool to study phenomena sensitive to Reynolds number is discussed. The National Transonic Facility (NTF), is in the calibration phase and the desired capability. Its usefulness, however, will be influenced by the ability of industry to develop model systems capable of withstanding the severe operating environment of the facility so necessary to achieve full scale Reynolds number, without degradation of accuracy, and at reasonable cost. The feasibility of designing models of advanced aerodynamic technology maneuvering aircraft and to achieve full scale Reynolds number for each configuration in the NTF are determined. It is concluded that the facility does not offer the potential for making tunnel to full scale data correlations for this type of aircraft configuration.

Griffin, S. A.↗
NASA NTRS1974

Jet engine exhaust emissions of high altitude commercial aircraft projected to 1990

Projected minimum levels of engine exhaust emissions that may be practicably achievable for future commercial aircraft operating at high-altitude cruise conditions are presented. The forecasts are based on:(1) current knowledge of emission characteristics of combustors and augmentors; (2) the status of combustion research in emission reduction technology; and (3) predictable trends in combustion systems and operating conditions as required for projected engine designs that are candidates for advanced subsonic or supersonic commercial aircraft fueled by either JP fuel, liquefied natural gas, or hydrogen. Results are presented for cruise conditions in terms of both an emission index (g constituent/kg fuel) and an emission rate (g constituent/hr).

Grobman, J.↗
NASA NTRS1974

Forecast of jet engine exhaust emissions for future high altitude commercial aircraft

Projected minimum levels of engine exhaust emissions that may be practicably achievable for future commercial aircraft operating at high altitude cruise conditions are presented. The forecasts are based on: (1) current knowledge of emission characteristics of combustors and augmentors; (2) the current status of combustion research in emission reduction technology; and (3) predictable trends in combustion systems and operating conditions as required for projected engine designs that are candidates for advanced subsonic or supersonic commercial aircraft. Results are presented for cruise conditions in terms of an emission index, g pollutant/kg fuel. Two sets of engine exhaust emission predictions are presented: the first, based on an independent NASA study and the second, based on the consensus of an ad hoc committee composed of industry, university, and government representatives. The consensus forecasts are in general agreement with the NASA forecasts.

Grobman, J.↗
NASA NTRS1980

The Quiet Short-haul Research Aircraft (QSRA)

The Quiet Short-Haul Research Aircraft (QSRA) is to be used as a flight facility for advanced flight experiments in terminal area operations. The overall objective of the QSRA program is to expand the technology base of the upper surface blowing propulsive lift concept in order to establish design criteria for the aircraft industry and to establish criteria for advanced STOL aircraft.

Martin, J. L.↗
NASA NTRS2017

Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) Project KDP-C Review

The topics discussed are the UAS-NAS project life-cycle and ARMD thrust flow down, as well as the UAS environments and how we operate in those environments. NASA's Armstrong Flight Research Center at Edwards, CA, is leading a project designed to help integrate unmanned air vehicles into the world around us. The Unmanned Aircraft Systems Integration in the National Airspace System project, or UAS in the NAS, will contribute capabilities designed to reduce technical barriers related to safety and operational challenges associated with enabling routine UAS access to the NAS. The project falls under the Integrated Systems Research Program office managed at NASA Headquarters by the agency's Aeronautics Research Mission Directorate. NASA's four aeronautics research centers - Armstrong, Ames Research Center, Langley Research Center, and Glenn Research Center - are part of the technology development project. With the use and diversity of unmanned aircraft growing rapidly, new uses for these vehicles are constantly being considered. Unmanned aircraft promise new ways of increasing efficiency, reducing costs, enhancing safety and saving lives 460265main_ED10-0132-16_full.jpg Unmanned aircraft systems such as NASA's Global Hawks (above) and Predator B named Ikhana (below), along with numerous other unmanned aircraft systems large and small, are the prime focus of the UAS in the NAS effort to integrate them into the national airspace. Credits: NASA Photos 710580main_ED07-0243-37_full.jpg The UAS in the NAS project envisions performance-based routine access to all segments of the national airspace for all unmanned aircraft system classes, once all safety-related and technical barriers are overcome. The project will provide critical data to such key stakeholders and customers as the Federal Aviation Administration and RTCA Special Committee 203 (formerly the Radio Technical Commission for Aeronautics) by conducting integrated, relevant system-level tests to adequately address safety and operational challenges of national airspace access by unmanned aircraft systems, or UAS. In the process, the project will work with other key stakeholders to define necessary deliverables and products to help enable such access. Within the project, NASA is focusing on five sub-projects. These five focus areas include assurance of safe separation of unmanned aircraft from manned aircraft when flying in the national airspace; safety-critical command and control systems and radio frequencies to enable safe operation of UAS; human factors issues for ground control stations; airworthiness certification standards for UAS avionics and integrated tests and evaluation designed to determine the viability of emerging UAS technology. Five Focus Areas of the UAS Integration in the NAS Project Separation Assurance Provide an assessment of how planned Next Generation Air Transportation System (NextGen) separation assurance systems, with different functional allocations, perform for UAS in mixed operations with manned aircraft Assess the applicability to UAS and the performance of NASA NextGen separation assurance systems in flight tests with realistic latencies and uncertain trajectories Assess functional allocations ranging from today's ground-based, controller-provided aircraft separation to fully autonomous airborne self-separation Communications Develop data and rationale to obtain appropriate frequency spectrum allocations to enable safe and efficient operation of UAS in the NAS Develop and validate candidate secure safety-critical command and control system/subsystem test equipment for UAS that complies with UAS international/national frequency regulations, standards and recommended practices and minimum operational and aviation system performance standards for UAS Perform analysis to support recommendations for integration of safety-critical command and control systems and air traffic control communications to ensure safe and efficient operation of UAS in the NAS Human Systems Integration Develop a research test bed and database to provide data and proof of concept for GCS - ground control station - operations in the NAS Coordinate with standards organizations to develop human-factors guidelines for GCS operation in the NAS Certification Define a UAS classification scheme and approach to determining Federal Aviation Regulation airworthiness requirements applicable to all UAS digital avionics Provide hazard and risk-related data to support development of type design criteria and best development practices Integrated Tests and Evaluation Integrate and test mature concepts from technical elements to demonstrate and test viability Evaluate the performance of technology development in a relevant environment (full-mission, human-in-the-loop simulations and flight tests)

outreach↗
NASA NTRS1994

Two Rotor Stratified Charge Rotary Engine (SCRE) Engine System Technology Evaluation

This report summarizes results of an evaluation of technology enablement component technologies as integrated into a two rotor Stratified Charge Rotary Engine (SCRE). The work constitutes a demonstration of two rotor engine system technology, utilizing upgraded and refined component technologies derived from prior NASA Contracts NAS3-25945, NAS3-24628 and NAS-23056. Technical objectives included definition of, procurement and assembly of an advanced two rotor core aircraft engine, operation with Jet-A fuel at Take-Off rating of 340 BHP (254kW) and operation at a maximum cruise condition of 255 BHP (190kW), 75% cruise. A fuel consumption objective of 0.435 LBS/BHP-Hr (265 GRS/kW-Hr) was identified for the maximum cruise condition. A critical technology component item, a high speed, unit injector fuel injection system with electronic control was defined, procured and tested in conjunction with this effort. The two rotor engine configuration established herein defines an affordable, advanced, Jet-A fuel capability core engine (not including reduction gear, propeller shaft and some aircraft accessories) for General Aviation of the mid-1990's and beyond.

Hoffman, T.↗
NASA NTRS1988

A review of technologies applicable to low-speed flight of high-performance aircraft investigated in the Langley 14- x 22-foot subsonic tunnel

An extensive research program has been underway at the NASA Langley Research Center to define and develop the technologies required for low-speed flight of high-performance aircraft. This 10-year program has placed emphasis on both short takeoff and landing (STOL) and short takeoff and vertical landing (STOVL) operations rather than on regular up and away flight. A series of NASA in-house as well as joint projects have studied various technologies including high lift, vectored thrust, thrust-induced lift, reversed thrust, an alternate method of providing trim and control, and ground effects. These technologies have been investigated on a number of configurations ranging from industry designs for advanced fighter aircraft to generic wing-canard research models. Test conditions have ranged from hover (or static) through transition to wing-borne flight at angles of attack from -5 to 40 deg at representative thrust coefficients.

Paulson, John W., Jr.↗
NASA NTRSDate not supplied

Evolution of Airspace Operations and Safety

NASA's vision of how the airspace will evolve and change by 2045. The progression will be driven in waves by technology with advances in automation and machine learning driving more dense traffic and more types of aircraft.

Airspace Operations and Safety↗
NASA NTRS2000

Gust Alleviation Using Direct Gust Measurement

The increasing competition in the market of civil aircraft leads to operating efficiency and passenger comfort being very important sales arguments. Continuous developments in jet propulsion technology helped to reduce energy consumption, as well as noise and vibrations due to the engines. The main problem with respect to ride comfort is, however, the transmittance of accelerations and jerkiness imposed by atmospheric turbulence from the wings to the fuselage. This 'gust' is also a design constraint: Light airplane structures help to save, energy, but are more critical to resist the loads imposed by turbulence. For both reasons, efficient gust alleviation is necessary to improve the performance of modern aircraft. Gust can be seen as a change in the angle of attack or as an additional varying vertical component of the headwind. The effect of gust can be very strong, since the same aerodynamic forces that keep the airplane flying are involved. Event though the frequency range of those changes is quite low, it is impossible for the pilot to alleviate gust manually. Besides, most of the time during the flight, the, autopilot maintains course and the attitude of flight. Certainly, most autopilots should be capable of damping the roughest parts of turbulence, but they are unable to provide satisfactory results in that field. A promising extension should be the application of subsidiary, control, where the inner (faster) control loop alleviates turbulence and the outer (slower) loop controls the attitude of flight. Besides the mentioned ride comfort, another reason for gust alleviation with respect to the fuselage is the sensibility of electrical devices to vibration and high values of acceleration. Many modern airplane designs--especially inherently instable military aircraft--are highly dependent on avionics. The lifetime and the reliability of these systems is thus essential.

Hoppe, Sven Marco↗
NASA NTRS1980

Aircraft noise control in the 1980's

It is pointed out that a need exists for the orderly development of technology and engineering methods for noise control of all types of aircraft. The nature and scope of aircraft noise problems are reviewed, and a description is provided of noise control progress made to date. The most serious aircraft noise problems confronting communities in the past two decades have been associated with the subsonic air carrier jet transport. Operational trends related to traffic growth and operational constraints are examined, and noise level trends are considered, taking into account engine cycle developments, the role of Federal noise certification, future noise exposures, and multiple noise sources. Advanced source noise reduction technology developments are discussed along with a noise impact assessment, and advanced operating procedures. Attention is also given to engine noise and sonic boom exposures in connection with supersonic air carrier aircraft, and exterior and interior noise control related to propeller/rotor aircraft.

Hubbard, H. H.↗
NASA NTRS1975

Evaluation of methods of reducing community noise impact around San Jose municipal airport

A computer simulation of the airport noise impact on the surrounding communities was used to evaluate alternate operational procedures, improved technology, and land use conversion as methods of reducing community noise impact in the airport vicinity. In addition, a constant density population distribution was analyzed for possible application to other airport communities with fairly uniform population densities and similar aircraft operational patterns. The introduction of sound absorption material (SAM) was found to reduce community noise annoyance by over 25 percent, and the introduction of refan was found to reduce community annoyance by over 60 percent. Replacing the present aircraft was found to reduce the noise problem to very small proportions, and the introduction of an advanced technology twin was found to essentially eliminate the community noise problem.

Glick, J. M.↗