Results for “pilot model” — Page 23

DOE OSTI2018

Development of a Spouted Bed Reactor for Chemical Looping Combustion

We have investigated a novel gas/solid contacting configuration for chemical looping combustion (CLC) with potential operating benefits. CLC configurations are typically able to achieve high fuel conversion efficiencies at the expense of high operating costs and low system reliability. The spouted fluid bed (SB) was identified as an improved reactor configuration for CLC, since it typically exhibits high heat transfer rates and offers the ability to use lower gas flows for material movement compared to bubbling beds (BB). Multiphase Flow with Interphase eXchanges (MFIX) software was used to establish a spouted fluid bed reactor design. An experimental setup was built to supplement the model. The experimental setup was also modified for testing under high temperature, reacting conditions (1073–1273 K). The setup was operated in either a spouted fluid bed or a bubbling bed regime to compare the performance attributes of each. Results for the reactor configurations are presented for CLC using a mixture of carbon monoxide and hydrogen as fuel. Compared to the bubbling bed, the spouted fluid bed reactor achieved an equivalent or better fuel conversion at a lower pressure drop over the material bed. The spouted fluid bed design represents a viable configuration to improve gas/solid contacting for efficient fuel conversion, lower energy requirements for material movement and increase operational robustness for CLC. The research laid the groundwork for future research into a multi-phase reacting flow CLC system. The system will be developed from computational fluid dynamic modeling and pilot-scale testing to expedite the development of CLC technologies.

Energy & Fuels↗

DOE OSTI2014

Final Report: Geoelectrical Measurement of Multi-Scale Mass Transfer Parameters

Mass transfer affects contaminant transport and is thought to control the efficiency of aquifer remediation at a number of sites within the Department of Energy (DOE) complex. An improved understanding of mass transfer is critical to meeting the enormous scientific and engineering challenges currently facing DOE. Informed design of site remedies and long-term stewardship of radionuclide-contaminated sites will require new cost-effective laboratory and field techniques to measure the parameters controlling mass transfer spatially and across a range of scales. In this project, we sought to capitalize on the geophysical signatures of mass transfer. Previous numerical modeling and pilot-scale field experiments suggested that mass transfer produces a geoelectrical signature—a hysteretic relation between sampled (mobile-domain) fluid conductivity and bulk (mobile + immobile) conductivity—over a range of scales relevant to aquifer remediation. In this work, we investigated the geoelectrical signature of mass transfer during tracer transport in a series of controlled experiments to determine the operation of controlling parameters, and also investigated the use of complex-resistivity (CR) as a means of quantifying mass transfer parameters in situ without tracer experiments. In an add-on component to our grant, we additionally considered nuclear magnetic resonance (NMR) to help parse mobile from immobile porosities. Including the NMR component, our revised study objectives were to: 1. Develop and demonstrate geophysical approaches to measure mass-transfer parameters spatially and over a range of scales, including the combination of electrical resistivity monitoring, tracer tests, complex resistivity, nuclear magnetic resonance, and materials characterization; and 2. Provide mass-transfer estimates for improved understanding of contaminant fate and transport at DOE sites, such as uranium transport at the Hanford 300 Area. To achieve our objectives, we implemented a 3-part research plan involving (1) development of computer codes and techniques to estimate mass-transfer parameters from time-lapse electrical data; (2) bench-scale experiments on synthetic materials and materials from cores from the Hanford 300 Area; and (3) field demonstration experiments at the DOE’s Hanford 300 Area. In a synergistic add-on to our workplan, we analyzed data from field experiments performed at the DOE Naturita Site under a separate DOE SBR grant, on which PI Day-Lewis served as co-PI. Techniques developed for application to Hanford datasets also were applied to data from Naturita.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2014

Geoelectrical Measurement of Multi-Scale Mass Transfer Parameters

Mass transfer affects contaminant transport and is thought to control the efficiency of aquifer remediation at a number of sites within the Department of Energy (DOE) complex. An improved understanding of mass transfer is critical to meeting the enormous scientific and engineering challenges currently facing DOE. Informed design of site remedies and long-term stewardship of radionuclide-contaminated sites will require new cost-effective laboratory and field techniques to measure the parameters controlling mass transfer spatially and across a range of scales. In this project, we sought to capitalize on the geophysical signatures of mass transfer. Previous numerical modeling and pilot-scale field experiments suggested that mass transfer produces a geoelectrical signature—a hysteretic relation between sampled (mobile-domain) fluid conductivity and bulk (mobile + immobile) conductivity—over a range of scales relevant to aquifer remediation. In this work, we investigated the geoelectrical signature of mass transfer during tracer transport in a series of controlled experiments to determine the operation of controlling parameters, and also investigated the use of complex-resistivity (CR) as a means of quantifying mass transfer parameters in situ without tracer experiments. In an add-on component to our grant, we additionally considered nuclear magnetic resonance (NMR) to help parse mobile from immobile porosities. Including the NMR component, our revised study objectives were to: 1. Develop and demonstrate geophysical approaches to measure mass-transfer parameters spatially and over a range of scales, including the combination of electrical resistivity monitoring, tracer tests, complex resistivity, nuclear magnetic resonance, and materials characterization; and 2. Provide mass-transfer estimates for improved understanding of contaminant fate and transport at DOE sites, such as uranium transport at the Hanford 300 Area. To achieve our objectives, we implemented a 3-part research plan involving (1) development of computer codes and techniques to estimate mass-transfer parameters from time-lapse electrical data; (2) bench-scale experiments on synthetic materials and materials from cores from the Hanford 300 Area; and (3) field demonstration experiments at the DOE’s Hanford 300 Area. In a synergistic add-on to our workplan, we analyzed data from field experiments performed at the DOE Naturita Site under a separate DOE SBR grant, on which PI Day-Lewis served as co-PI. Techniques developed for application to Hanford datasets also were applied to data from Naturita.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2022

Direct conversion of Light Hydrocarbons to Olefins (Final report)

Reaction35 is developing a new industrial process that is substantially different from the traditional standalone dehydrogenation process practiced in industry such as Oleflex® and Catofin®. Those processes have substantial energy consumption and loss of feed constraints. The Reaction35 process is based on using molecular bromine to activate the alkane (e.g., nbutane) by forming highly reactive butyl bromides. The butyl bromides are easily converted to nbutylenes (final product) and hydrogen bromide. The hydrogen bromide generated in bromination and dehydrobromination is oxidized with air, recovering the molecular bromine which is reused. The overall result is a process with a favorably low energy consumption and less than 1 % overall loss of feed compared to more than 5 % for the direct dehydrogenation processes. During the grant period, several important aspects of the technology have been developed further. The major effort was the hydrogenation catalyst step development. The hydrogenation catalyst is used for recovery of the polybromobutanes to the bromobutanes intermediates. The scientific field regarding dibromo- and polybromoalkanes has not been extensively studied, which necessitated that Reaction35 performs a full study of a number of catalysts and the various experimental conditions that influence the hydrogenation reaction. Currently, Reaction35 has completed its catalyst selection and preliminary experimental parameters optimization. This will allow for the construction of an engineering model for a pilot unit testing.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

NASA NTRS1968

Human transfer characteristics in flight and ground simulation for the roll tracking task Final technical report

Mathematical models of human pilot performance in roll tracking task derived from flight simulator and T 33 aircraft situations

Newell, F. D.↗

NASA NTRS1975

Effects of control-stick parameters on tracking performance in a vibration environment

A set of manual control experiments was conducted to determine the effects of control stick parameters on tracking performance in a vibration environment. Primary experimental variables were stick design parameters, stick location, and presence or absence of vibration. Considerable effect on control activity suggests that stick design parameters will significantly influence overall performance in systems that respond at vibration frequencies. Stick location had no significant effect on either tracking or biodynamic performance measures. The vibration correlated component of tracking error was relatively small. A model based guide for the design of control sticks in a vibration environment is described. This model is based on the state variable model for pilot/vehicle systems. Effects of vibration are represented as additional model elements and by changes in pilot related parameters of the tracking model.

Levison, W. H.↗

NASA NTRS1982

High angle-of-attack characteristics of three-surface fighter aircraft

As part of a research program aimed at providing information on the high angle-of-attack characteristics of three-surface fighter concepts incorporating a close-coupled canard, an investigation is being conducted on two specific configurations based on the F-18 and F-15 designs. The study configurations are being subjected to a wide range of tests including wind-tunnel tests, dynamic model tests, and piloted simulation. This paper summarizes the results obtained to date in this study. High-alpha results in the areas of static stability, damping, and control characteristics are reviewed and some of the more significant aerodynamic phenomena are identified.

Croom, M. A.↗

NASA NTRS1987

Simulator manufacturers' requirements

Simulator manufacturers must continue to provide the customers the latest wind shear models available for pilot training. The release of the JAWS data package enabled the provision of a much more realistic wind shear package to the customer rather than just the standard six SRI wind shear profiles currently in use. In this brief presentation, the steps taken in implementing the JAWS data into the FAA 727 simulator are highlighted.

Reilly, David R.↗

NASA NTRS1987

The temperature dependence of inelastic light scattering from small particles for use in combustion diagnostic instrumentation

A computer calculation of the expected angular distribution of coherent anti-Stokes Raman scattering (CARS) from micrometer size polystyrene spheres based on a Mie-type model, and a pilot experiment to test the feasibility of measuring CARS angular distributions from micrometer size polystyrene spheres by simply suspending them in water are discussed. The computer calculations predict a very interesting structure in the angular distributions that depends strongly on the size and relative refractive index of the spheres.

Cloud, Stanley D.↗

NASA NTRS1989

Simulation evaluation of transition and hover flying qualities of a mixed-flow, remote-lift STOVL aircraft

Using a generalized simulation model developed for piloted evaluations of STOVL aircraft, an initial fixed-base simulation of a mixed-flow, remote-lift configuration has been completed. Objectives were to evaluate the integration of the aircraft's flight and propulsion controls to achieve good flying qualities throughout the low-speed flight envelope; to determine control power used during transition, hover, and vertical landing; and to evaluate the transition flight envelope considering the influence of thrust deflection of the remote-lift component. Pilots' evaluations indicated that Level 1 flying qualities could be achieved for deceleration to hover in instrument conditions, for airfield landings, and for recovery to a small ship when attitude and velocity stabilization and command augmentation control modes were provided. Level 2 flying qualities were obtained for these same tasks when only the attitude command mode was used, leaving the pilot to perform the task of thrust management required to control the flight-path and speed in transition and the horizontal and vertical translational velocities in hover. Thrust margins were defined for vertical landing as a function of ground effect and hot-gas ingestion.

Franklin, James A.↗

NASA NTRS1990

Map display design

This paper presents a cognitive model of a pilot's navigation task and describes an experiment comparing a visual momentum map display to the traditional track-up and north-up approaches. The data show the advantage to a track-up map is its congruence with the ego-centered forward view; however, the development of survey knowledge is hindered by the inconsistency of the rotating display. The stable alignment of a north-up map aids the acquisition of survey knowledge, but there is a cost associated with the mental rotation of the display to a track-up alignment for ego-centered tasks. The results also show that visual momentum can be used to reduce the mental rotation costs of a north-up display.

Aretz, Anthony J.↗

NASA NTRS1992

Parameterization of surface heat fluxes above a forest with satellite thermal sensing

The authors discuss the feasibility of determining the surface flux of sensible heat from forests with surface temperatures measured by satellites together with temperature soundings in the unstable atmospheric boundary layer (ABL). The latent heat flux is derived from the sensible heat flux by means of the energy budget. The study makes use of data collected during HAPEX-MOBILHY (Hydrologic Atmospheric Pilot Experiment-Modelization du Bilan Hydrique). The methodology is based on turbulence similarity for the unstable ABL. The surface temperature data were derived from measurements by the advanced very high resolution radiometer (AVHRR) aboard the NOAA-9 satellite; the atmospheric profiles were obtained by radiosondes.

Brutsaert, Wilfried↗

NASA NTRS1998

Accommodating Actuator Failures in Flight Control Systems

A technique for the design of flight control systems that can accommodate a set of actuator failures is presented. As employed herein, an actuator failure is defined as any change in the parametric model of the actuator which can adversely affect actuator performance. The technique is based upon the formulation of a fixed feedback topology which ensures at least stability in the presence of the failures in the set. The fixed compensation is obtained from a loop-shaping design procedure similar to Quantitative Feedback Theory and provides stability robustness in the presence of uncertainty in the vehicle dynamics caused by the failures. System adaptation to improve performance after actuator failure(s) occurs through a static gain adjustment in the compensator followed by modification of the system prefilter. Precise identification of the vehicle dynamics is unnecessary. Application to a single-input, single-output design using a simplified model of the longitudinal dynamics of the NASA High Angle of Attack Research Vehicle is discussed. Non-real time simulations of the system including a model of the pilot demonstrate the effectiveness and limitations of the approach.

Hess, R. A.↗

NASA NTRS1996

An Overview of Controls and Flying Qualities Technology on the F/A-18 High Alpha Research Vehicle

The NASA F/A-18 High Alpha Research Vehicle (HARV) has been the flight test bed of a focused technology effort to significantly increase maneuvering capability at high angles of attack. Development and flight test of control law design methodologies, handling qualities metrics, performance guidelines, and flight evaluation maneuvers are described. The HARV has been modified to include two research control effectors, thrust vectoring, and actuated forebody strakes in order to provide increased control power at high angles of attack. A research flight control system has been used to provide a flexible, easily modified capability for high-angle-of-attack research controls. Different control law design techniques have been implemented and flight-tested, including eigenstructure assignment, variable gain output feedback, pseudo controls, and model-following. Extensive piloted simulation has been used to develop nonlinear performance guide-lines and handling qualities criteria for high angles of attack. This paper reviews the development and evaluation of technologies useful for high-angle-of-attack control. Design, development, and flight test of the research flight control system, control laws, flying qualities specifications, and flight test maneuvers are described. Flight test results are used to illustrate some of the lessons learned during flight test and handling qualities evaluations.

Pahle, Joseph W.↗

NASA NTRS2004

A Real-Time Satellite-Based Icing Detection System

Aircraft icing is one of the most dangerous weather conditions for general aviation. Currently, model forecasts and pilot reports (PIREPS) constitute much of the database available to pilots for assessing the icing conditions in a particular area. Such data are often uncertain or sparsely available. Improvements in the temporal and areal coverage of icing diagnoses and prognoses would mark a substantial enhancement of aircraft safety in regions susceptible to heavy supercooled liquid water clouds. The use of 3.9 microns data from meteorological satellite imagers for diagnosing icing conditions has long been recognized (e.g., Ellrod and Nelson, 1996) but to date, no explicit physically based methods have been implemented. Recent advances in cloud detection and cloud property retrievals using operational satellite imagery open the door for real-time objective applications of those satellite datasets for a variety of weather phenomena. Because aircraft icing is related to cloud macro- and microphysical properties (e.g., Cober et al. 1995), it is logical that the cloud properties from satellite data would be useful for diagnosing icing conditions. This paper describes the a prototype realtime system for detecting aircraft icing from space.

Minnis, Patrick↗

NASA NTRSDate not supplied

Flight Simulator Demonstration and Certification Implications of Powertrain Failure Mitigation in a Partial Turboelectric Aircraft

The Single-aisle Turboelectric AiRCraft with Aft Boundary Layer propulsor (STARC ABL) is a concept aircraft with a partial turboelectric powertrain. The complexity and integrated nature of the partial turboelectric powertrain architecture presents failure modes and hazards not found in conventional aircraft propulsion designs. Previously, various electrical and mechanical faults and associated recovery modes were demonstrated in a dynamic model of the powertrain. It was shown that certain faults were catastrophic without recovery logic, due specifically to the interaction of the subsystems. However, in each case, the logic, known as a reversionary control mode, enabled continued operation with assumed sufficient thrust to maintain safe flight. The current work evaluates the powertrain faults and recovery strategies using a full aircraft model in a piloted flight simulator, and places it in the context of current regulatory practice. Faults initiated in flight were successfully mitigated, with the accommodated aircraft subsequently evaluated against certification requirements for three-engine aircraft, which were shown to be appropriate for the STARC-ABL configuration.

STARC-ABL↗

NASA NTRSDate not supplied

Flight Simulator Demonstration and Certification Implications of Powertrain Failure Mitigation in a Partial Turboelectric Aircraft

The Single-aisle Turboelectric AiRCraft with Aft Boundary Layer propulsor (STARC ABL) is a concept aircraft with a partial turboelectric powertrain. The complexity and integrated nature of the partial turboelectric powertrain architecture presents failure modes and hazards not found in conventional aircraft propulsion designs. Previously, various electrical and mechanical faults and associated recovery modes were demonstrated in a dynamic model of the powertrain. It was shown that certain faults were catastrophic without recovery logic, due specifically to the interaction of the subsystems. However, in each case, the logic, known as a reversionary control mode, enabled continued operation with assumed sufficient thrust to maintain safe flight. The current work evaluates the powertrain faults and recovery strategies using a full aircraft model in a piloted flight simulator, and places it in the context of current regulatory practice. Faults initiated in flight were successfully mitigated, with the accommodated aircraft subsequently evaluated against certification requirements for three-engine aircraft, which were shown to be appropriate for the STARC-ABL configuration.

STARC-ABL↗

NASA NTRS2023

Flight Simulator Demonstration and Certification Implications of Powertrain Failure Mitigation in a Partial Turboelectric Aircraft

The Single-aisle Turboelectric AiRCraft with Aft Boundary Layer propulsor (STARC ABL) is a concept aircraft with a partial turboelectric powertrain. The complexity and integrated nature of the partial turboelectric powertrain architecture presents failure modes and hazards not found in conventional aircraft propulsion designs. Previously, various electrical and mechanical faults and associated recovery modes were demonstrated in a dynamic model of the powertrain. It was shown that certain faults were catastrophic without recovery logic, due specifically to the interaction of the subsystems. However, in each case, the logic, known as a reversionary control mode, enabled continued operation with assumed sufficient thrust to maintain safe flight. The current work evaluates the powertrain faults and recovery strategies using a full aircraft model in a piloted flight simulator, and places it in the context of current regulatory practice. Faults initiated in flight were successfully mitigated, with the accommodated aircraft subsequently evaluated against certification requirements for three-engine aircraft, which were shown to be appropriate for the STARC-ABL configuration.

certification↗