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Results for “Distributed Propulsion”

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 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Probabilistic Structural Analysis Methods for select space propulsion system structural components (PSAM)

The objective is the development of several modular structural analysis packages capable of predicting the probabilistic response distribution for key structural variables such as maximum stress, natural frequencies, transient response, etc. The structural analysis packages are to include stochastic modeling of loads, material properties, geometry (tolerances), and boundary conditions. The solution is to be in terms of the cumulative probability of exceedance distribution (CDF) and confidence bounds. Two methods of probability modeling are to be included as well as three types of structural models - probabilistic finite-element method (PFEM); probabilistic approximate analysis methods (PAAM); and probabilistic boundary element methods (PBEM). The purpose in doing probabilistic structural analysis is to provide the designer with a more realistic ability to assess the importance of uncertainty in the response of a high performance structure. Probabilistic Structural Analysis Method (PSAM) tools will estimate structural safety and reliability, while providing the engineer with information on the confidence that should be given to the predicted behavior. Perhaps most critically, the PSAM results will directly provide information on the sensitivity of the design response to those variables which are seen to be uncertain.

Cruse, T. A.↗
NASA NTRS2017

Model Validation for Propulsion - On the TFNS and LES Subgrid Models for a Bluff Body Stabilized Flame

With advances in computational power and availability of distributed computers, the use of even the most complex of turbulent chemical interaction models in combustors and coupled analysis of combustors and turbines is now possible and more and more affordable for realistic geometries. Recent more stringent emission standards have enticed the development of more fuel-efficient and low-emission combustion system for aircraft gas turbine applications. It is known that the NOx emissions tend to increase dramatically with increasing flame temperature. It is well known that the major difficulty, when modeling the turbulence-chemistry interaction, lies in the high non-linearity of the reaction rate expressed in terms of the temperature and species mass fractions. The transport filtered density function (FDF) model and the linear eddy model (LEM), which both use local instantaneous values of the temperature and mass fractions, have been shown to often provide more accurate results of turbulent combustion. In the present, the time-filtered Navier-Stokes (TFNS) approach capable of capturing unsteady flow structures important for turbulent mixing in the combustion chamber and two different subgrid models, LEM-like and EUPDF-like, capable of emulating the major processes occurring in the turbulence-chemistry interaction will be used to perform reacting flow simulations of a selected test case. The selected test case from the Volvo Validation Rig was documented by Sjunnesson.

bluff body↗
NASA NTRS2019

Evaluation of Electrical System Requirements for Implementing Turbine Electrified Energy Management

Turbine Electrified Energy Management (TEEM) is a concept concerned with the management of energy in an electrified propulsion system. The management of energy in the hybrid-electric architecture has potential to benefit the turbomachinery and the aircraft it powers. The concept is particularly useful for improving operability during transient operation and could be leveraged to design a better performing engine. The concept utilizes electric machines coupled to the engine shafts and an electric power distribution system that includes energy storage. A controller is used to decide when and how energy is moved around the electrified propulsion system, particularly when considering energy conversion between mechanical and electrical forms. Prior work has shown that the electric machines can be used to supply/or extract supplemental power to/from the engine shafts to improve their operability and achieve or enable propulsion efficiency and performance benefits. However, the previous studies did not consider the practical constraints of the electrical machines and energy storage devices that are required for implementing the TEEM system architecture concept. This paper presents an integrated engine and electrical system model that is used to evaluate the electrical system requirements. The model captures the physics of the conceptual, Advanced Geared Turbofan 30,000lbf (AGTF30) engine, which features advanced technologies such as a compact gas turbine and a variable area fan nozzle. For this work, the engine is augmented with electrical system components that allow for the implementation of the TEEM concept. The evaluation presented suggests the potential of the TEEM concept to provide performance benefits for a turbofan engine.

electrified↗
NASA NTRS2019

Evaluation of Electrical System Requirements for Implementing Turbine Electrified Energy Management

Turbine Electrified Energy Management (TEEM) is a concept concerned with the management of energy in an electrified propulsion system. The management of energy in the hybrid-electric architecture has potential to benefit the turbomachinery and the aircraft it powers. The concept is particularly useful for improving operability during transient operation and could be leveraged to design a better performing engine. The concept utilizes electric machines coupled to the engine shafts and an electric power distribution system that includes energy storage. A controller is used to decide when and how energy is moved around the electrified propulsion system, particularly when considering energy conversion between mechanical and electrical forms. Prior work has shown that the electric machines can be used to supply/or extract supplemental power to/from the engine shafts to improve their operability and achieve or enable propulsion efficiency and performance benefits. However, the previous studies did not consider the practical constraints of the electrical machines and energy storage devices that are required for implementing the TEEM system architecture concept. This paper presents an integrated engine and electrical system model that is used to evaluate the electrical system requirements. The model captures the physics of the conceptual, Advanced Geared Turbofan 30,000lbf (AGTF30) engine, which features advanced technologies such as a compact gas turbine and a variable area fan nozzle. For this work, the engine is augmented with electrical system components that allow for the implementation of the TEEM concept. The evaluation presented suggests the potential of the TEEM concept to provide performance benefits for a turbofan engine.

hybrid electric propulsion↗
NASA NTRS1941

Effect of Body Nose Shape on the Propulsive Efficiency of a Propeller

Report presents the results of an investigation of the propulsive efficiency of three adjustable propellers of 10-foot diameter operated in front of four body nose shapes, varying from streamline nose that continued through the propeller plane in the form of a large spinner to a conventional open-nose radial-engine cowling. One propeller had airfoil sections close to the hub, the second had conventional round blade shanks, and the third differed from the second only in pitch distribution. The blade-angle settings ranged from 20 degrees to 55 degrees at the 0.75 radius. The effect of the body nose shape on propulsive efficiency may be divided into two parts: (1) the change in the body drag due to the propeller slipstream and (2) the change in propeller load distribution due to the change in velocity caused by the body. For the nose shape tested in the report, the first effect is shown to be very small; therefore, the chief emphasis of the report is confined to the second effect.

Stickle, George W↗
DOE OSTI2023

Concentration fluctuations and flammability of cryo-compressed hydrogen and methane jets

Compressed hydrogen stored at cryogenic temperatures has a much higher density than room-temperature storage, which enables large-scale hydrogen storage and transport. An understanding of the release of cryogenic hydrogen from pressurized vessels is needed to evaluate the risk and safety concerns with the use of this fuel. Here, the present work extends the analysis of previous experimental studies that measured the gas concentrations of cryo-compressed hydrogen jets and methane jets using a laser Raman scattering diagnostic system. Since the Raman signals are very small, a denoising algorithm was applied to significantly reduce the noise to enable statistical analysis of the data. The transient features of the turbulent jets were characterized by their concentration intermittencies and probability density functions (PDFs). A two-part PDF was developed to predict the bimodal features of the jet concentration distributions. Then, the flammability factors of the cryogenic jets were calculated based on the intermittency and the PDF.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2025

Colorado Alternatively Powered Aircraft Airport Infrastructure Study

Advanced Air Mobility encompasses emerging technologies in propulsion of general aviation and commuter aircraft for the purpose of moving passengers and goods. The State of Colorado has a strong aerospace and aviation legacy, and this research explores the potential energy implications of a transition from traditional aircraft propulsion systems to more-electric, full electric and hydrogen powered aircraft in flight schools, and small community air service utilizing NASA's Regional Air Mobility Model. Effort includes identifying potential energy needs and cost-effective solutions to support those emerging needs analyzing potential benefits on on-site generation and storage to optimize energy systems.Advanced Air Mobility encompasses emerging technologies in propulsion of general aviation and commuter aircraft for the purpose of moving passengers and goods. The State of Colorado has a strong aerospace and aviation legacy, and this research explores the potential energy implications of a transition from traditional aircraft propulsion systems to more-electric, full electric and hydrogen powered aircraft in flight schools, and small community air service utilizing NASA's Regional Air Mobility Model. Effort includes identifying potential energy needs and cost-effective solutions to support those emerging needs analyzing potential benefits on on-site generation and storage to optimize energy systems.

33 ADVANCED PROPULSION SYSTEMS↗
NASA NTRS1981

Dispersive Doppler measurement of the electron content of the torus of Io

As Voyager 1 made its swing-by of Io, it passed through and behind the satellite's plasma torus. The phase paths of the coherent 13 cm and 3.6-cm wavelength signals transmitted from the spacecraft were shortened differentially by the plasma, resulting in the observation of a dispersive Doppler signature in the signals received at the NASA/Jet Propulsion Laboratory (deep space network) stations. Ray path integration through three different models of the electron distribution of the torus of Io (Warwick et al. 1979; Birmingham et al. 1981; Bagenal et al., 1981) have been performed. The results of the integrations are compared with the dispersive Doppler data.

Levy, G. S.↗
NASA NTRS1993

The evolving trend in spacecraft health analysis

The Space Flight Operations Center inaugurated the concept of a central data repository for spacecraft data and the distribution of computing power to the end users for that data's analysis at the Jet Propulsion Laboratory. The Advanced Multimission Operations System is continuing the evolution of this concept as new technologies emerge. Constant improvements in data management tools, data visualization, and hardware lead to ever expanding ideas for improving the analysis of spacecraft health in an era of budget constrained mission operations systems. The foundation of this evolution, its history, and its current plans will be discussed.

Kirkpatrick, Russell L.↗
NASA NTRS2012

Health-Enabled Smart Sensor Fusion Technology

A process was designed to fuse data from multiple sensors in order to make a more accurate estimation of the environment and overall health in an intelligent rocket test facility (IRTF), to provide reliable, high-confidence measurements for a variety of propulsion test articles. The object of the technology is to provide sensor fusion based on a distributed architecture. Specifically, the fusion technology is intended to succeed in providing health condition monitoring capability at the intelligent transceiver, such as RF signal strength, battery reading, computing resource monitoring, and sensor data reading. The technology also provides analytic and diagnostic intelligence at the intelligent transceiver, enhancing the IEEE 1451.x-based standard for sensor data management and distributions, as well as providing appropriate communications protocols to enable complex interactions to support timely and high-quality flow of information among the system elements.

Wang, Ray↗
NASA NTRS2018

Particle Size Calibration Testing in the NASA Propulsion Systems Laboratory

The particle size characterization portion of the 2017 Propulsion Systems Laboratory (PSL) Cloud Calibration is described. The work focuses on characterizing the particle size distribution of the icing cloud as a function of simulated atmospheric conditions.These results will aid in upcoming ice crystal and supercooled liquid icing tests in PSL. Measurements acquired with the Phase Doppler Interferometer and High Speed Imaging instruments are presented. Experimental results indicate that the particle size distribution is primarily a function nozzle air and water pressures, and that air speed is not a significant effect for ice crystal clouds in PSL and both thermodynamic conditions and air speed are not significant effects for supercooled liquid water clouds in PSL.

Engine icing↗
NASA NTRS2019

Particle Size Calibration Testing in the NASA Propulsion Systems Laboratory

The particle size characterization portion of the 2017 Propulsion Systems Laboratory (PSL) Cloud Calibration is described. The work focuses on characterizing the particle size distribution of the icing cloud as a function of simulated atmospheric conditions.These results will aid in upcoming ice crystal and supercooled liquid icing tests in PSL. Measurements acquired with the Phase Doppler Interferometer and High Speed Imaging instruments are presented. Experimental results indicate that the particle size distribution is primarily a function nozzle air and water pressures, and that air speed is not a significant effect for ice crystal clouds in PSL and both thermodynamic conditions and air speed are not significant effects for supercooled liquid water clouds in PSL.

Engine Icing↗
NASA NTRS2020

Accessibility Design and Operational Considerations in the Development of Urban Aerial Mobility Vehicles and Networks

Urban aerial mobility vehicles and networks have recently gained considerable interest in the aviation community. These small, short-range vehicles with all-electric or hybrid-electric propulsion systems, tailored to metropolitan aerial transportation needs, promise to radically change passenger mobility and cargo distribution in cities. Accessibility issues have not been a major consideration in UAM vehicle and network discussions to date. This paper seeks to help change that.

Young, Larry A.↗
DOE OSTI2019

Electricity Cost for Electric Vehicle Fast Charging

As the adoption of plug-in electric vehicles (PEVs) continues to grow, so does the development of a network of fast-charging stations to support long-distance travel and provide alternatives to residential and workplace charging. Fast charging, however, could be significantly more expensive than residential/workplace charging, mainly due to high power consumption and low utilization. This poster highlights NREL's review of the current cost of electricity for PEV fast charging in the United States as well as its evaluation of alternative charting options to mitigate electricity costs for public fast-charging stations via on-site electricity generation (from photovoltaics) and storage.

25 ENERGY STORAGE↗
NASA NTRS2017

A Novel UAV Electric Propulsion Testbed for Diagnostics and Prognostics

This paper presents a novel hardware-in-the-loop (HIL) testbed for systems level diagnostics and prognostics of an electric propulsion system used in UAVs (unmanned aerial vehicle). Referencing the all electric, Edge 540T aircraft used in science and research by NASA Langley Flight Research Center, the HIL testbed includes an identical propulsion system, consisting of motors, speed controllers and batteries. Isolated under a controlled laboratory environment, the propulsion system has been instrumented for advanced diagnostics and prognostics. To produce flight like loading on the system a slave motor is coupled to the motor under test (MUT) and provides variable mechanical resistance, and the capability of introducing nondestructive mechanical wear-like frictional loads on the system. This testbed enables the verification of mathematical models of each component of the propulsion system, the repeatable generation of flight-like loads on the system for fault analysis, test-to-failure scenarios, and the development of advanced system level diagnostics and prognostics methods. The capabilities of the testbed are extended through the integration of a LabVIEW-based client for the Live Virtual Constructive Distributed Environment (LVCDC) Gateway which enables both the publishing of generated data for remotely located observers and prognosers and the synchronization the testbed propulsion system with vehicles in the air. The developed HIL testbed gives researchers easy access to a scientifically relevant portion of the aircraft without the overhead and dangers encountered during actual flight.

Gorospe, George E., Jr.↗
DOE OSTI2018

Correlation of nanoparticle size distribution features to spatiotemporal flame luminosity in gasoline direct injection engines

Particle size distribution measured by mobility instruments is a common diagnostic used to characterize ultrafine and nanoparticle emissions in engine exhaust; however, some features of particle size distribution data are poorly correlated to in-cylinder combustion phenomena. In this work, in-cylinder spatiotemporal flame luminosity is quantitatively correlated to features in the solid particle size distribution measured in the exhaust of a gasoline direct injection engine operating in lean and stoichiometric combustion modes. A multi-channel optical sensor was used to measure diffusion flame light intensity in different areas of the combustion chamber. Furthermore, total solid particle number and particle size distribution in the exhaust were measured using a scanning mobility particle sizer after a catalytic stripper that removed semi-volatile compounds. Results of the experiments showed that different flame phenomenon resulted in distinct particle size distribution characteristics. A large accumulation mode (particles with diameter of 50–100 nm) in the particle size distribution from stoichiometric engine operation with early injection resulted from anomalous diffusion flames like piston-top pool fires. In lean operation incorporating a secondary fuel injection, particle emissions were dominated by flame propagation through fuel-rich regions of the combustion chamber resulting in a comparatively broad particle size distribution. More generally, this work illustrates how particle size distribution data can be more accurately used to diagnose soot formation in gasoline direct injection engines.

33 ADVANCED PROPULSION SYSTEMS↗
NASA NTRS2011

Redefining Tactical Operations for MER Using Cloud Computing

The Mars Exploration Rover Mission (MER) includes the twin rovers, Spirit and Opportunity, which have been performing geological research and surface exploration since early 2004. The rovers' durability well beyond their original prime mission (90 sols or Martian days) has allowed them to be a valuable platform for scientific research for well over 2000 sols, but as a by-product it has produced new challenges in providing efficient and cost-effective tactical operational planning. An early stage process adaptation was the move to distributed operations as mission scientists returned to their places of work in the summer of 2004, but they would still came together via teleconference and connected software to plan rover activities a few times a week. This distributed model has worked well since, but it requires the purchase, operation, and maintenance of a dedicated infrastructure at the Jet Propulsion Laboratory. This server infrastructure is costly to operate and the periodic nature of its usage (typically heavy usage for 8 hours every 2 days) has made moving to a cloud based tactical infrastructure an extremely tempting proposition. In this paper we will review both past and current implementations of the tactical planning application focusing on remote plan saving and discuss the unique challenges present with long-latency, distributed operations. We then detail the motivations behind our move to cloud based computing services and as well as our system design and implementation. We will discuss security and reliability concerns and how they were addressed

Mars↗