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At least 433 records · Page 24

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NASA NTRS2012

Application of an Optimal Tuner Selection Approach for On-Board Self-Tuning Engine Models

An enhanced design methodology for minimizing the error in on-line Kalman filter-based aircraft engine performance estimation applications is presented in this paper. It specific-ally addresses the under-determined estimation problem, in which there are more unknown parameters than available sensor measurements. This work builds upon an existing technique for systematically selecting a model tuning parameter vector of appropriate dimension to enable estimation by a Kalman filter, while minimizing the estimation error in the parameters of interest. While the existing technique was optimized for open-loop engine operation at a fixed design point, in this paper an alternative formulation is presented that enables the technique to be optimized for an engine operating under closed-loop control throughout the flight envelope. The theoretical Kalman filter mean squared estimation error at a steady-state closed-loop operating point is derived, and the tuner selection approach applied to minimize this error is discussed. A technique for constructing a globally optimal tuning parameter vector, which enables full-envelope application of the technology, is also presented, along with design steps for adjusting the dynamic response of the Kalman filter state estimates. Results from the application of the technique to linear and nonlinear aircraft engine simulations are presented and compared to the conventional approach of tuner selection. The new methodology is shown to yield a significant improvement in on-line Kalman filter estimation accuracy.

Simon, Donald L.↗

NASA NTRS1977

Seismic energy transmission in an intensively scattering environment

In order to account for some special features of lunar seismograms, namely, the gradual build-up of the signal, the extremely prolonged tail, and the lack of apparent coherence among three orthogonal components of ground motion, a statistical approach is proposed for describing transmission of seismic energy through a medium in which strong scattering takes place. A seismic diffusion theory is presented for a medium with randomly distributed scatterers of a given size distribution. A solution of the resulting diffusion equation for an impulsive energy source gives a curve which fairly closely reproduces the envelope of typical lunar impact seismograms. Since the model is based on constant diffusivity, long-range transmission will require a combination of diffusion and wave propagation treatments for accurate description.

Nakamura, Y.↗

NASA NTRS1998

Battery Systems for X-38 Crew Return Vehicle (CRV) and Deorbit Propulsion Stage (DPS)

A 28V 32 Ah cell Li/MnO2 and a 28V NiMH battery systems for the Deorbit Propulsion Stage (DPS) and the X-38 Crew Return Vehicle (CRV) are developed in Friwo-Silforkraft, Germany with the following objectives and approach: Provide safe battery designs for lowest volume and cost, and within schedule; Take advantage of less complex requests for V201 vs OPS CRV to simplify design and reduce cost; Use only existing commercial cell designs as building blocks for larger battery; Derive battery designs from the ASTRO-SPAS design which is the largest lithium battery design with Shuttle flight experience; Place maximum amount of battery energy on DPS; DPS battery is non rechargeable; and CRV batteries are rechargeable. This paper contains the following sections: a brief introduction on CRV requirements, CRV advantages over Soyuz, and X-38 programs; Battery objectives and approach; Battery requirements and groundrules (performance, on-orbit operation, etc); Design trades, solutions, redundancy plan, and margins; Envelope, size, and mass; Interfaces (structural, electrical & thermal); and Deviation from OPS CRV.

Darcy, Eric↗

NASA NTRS2020

A Modeling Approach for Handling Qualities and Controls Safety Analysis of Electric Air Taxi Vehicles

The combination of modern advances in electric propulsion, fly-by-wire controls, autonomy, and increasing demand for short range air taxi operations, is currently producing an outburst of vehicle designs more diverse than ever before. Advanced software tools are needed to support the rapid and safe introduction of any design into the airspace, including the safety of the deployed flight control system and vehicle handling qualities. This paper presents a methodology for building air taxi vehicle models with distributed electric propulsion for use in analyzing flight control system safety at the conceptual design level.The approach builds on existing software tools capable of outputting aeromechanics-based linear perturbation models for Vertical Take-off and Landing vehicles with multiple rotors. Rotor torque inputs are then converted into equivalent voltage control inputs, and the linear state and input dynamics matrices are modified to include electric motor dynamics with common parameters for direct-current electric motors. The linear perturbation dynamics are then stitched across multiple operating points into a quasi-Linear Parameter Varying model that covers the full flight envelope. A Model Predictive Controller is developed for use with the full envelope model, and a tradeoff analysis between handling quality and motor requirements is demonstrated using a six passenger NASA air taxi reference design.

Urban Air Mobility↗

DOE OSTI2022

Smart, Connected Manufactured Housing Solutions through High-Performance Design. Final CRADA report

This report focuses on HVAC, domestic hot water, and miscellaneous electric loads via voluntary opportunities that may arise from partnerships with utilities, as well as future US Environmental Protection Agency ENERGY STAR and DOE Zero Energy Ready Manufactured Home programs. Phase I of this project has begun the technical dialogue toward developing an implementation plan among DOE’s Oak Ridge National Laboratory, Clayton Manufactured Homes, and US Department of Housing and Urban Development Code manufactured housing stakeholders. These activities have focused on delivering high-performance design through integration of technology. Project tasks include the following: Identifying baseline energy analysis resources opportunities from a variety of DOE and utility stakeholders; Developing a smart home and business solution by leveraging existing utility programs working with Smart Homes Partners resources such as ACE IoT Solutions, Google Nest, and Ecobee; Developing improved smarter ventilation systems with industry ventilation partners such as the Madison Group; Developing improved building science QA/QC testing equipment with manufacturers such as The Energy Conservatory, and supporting other feasible concepts vetted under DOE’s Advanced Buildings Collaborative with Slipstream, reinventing HVAC in manufactured housing; and, Developing smart home short- and long-term viable technical solutions in coordination with Clayton Manufactured Homes in new and/or revitalized community scales for future Phase II prototype demonstrations, which may include design (and perhaps construction) of single-section homes targeting rental property developers and multi-section homes targeting low- to middle-income affordable housing community developers Given the ongoing US Department of Energy (DOE) rulemaking activities, baseline energy analysis assessments of envelope prescriptive and Uo (i.e., the overall thermal energy efficiency of the home in British thermal units per square foot of exterior heat loss/gain surfaces) measures were removed from the scope of Phase I of this project.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

NASA NTRS1994

Design and testing of a model CELSS chamber robot

A robot system for use in an enclosed environment was designed and tested. The conceptual design will be used to assist in research performed by the Controlled Ecological Life Support System (CELSS) project. Design specifications include maximum load capacity, operation at specified environmental conditions, low maintenance, and safety. The robot system must not be hazardous to the sealed environment, and be capable of stowing and deploying within a minimum area of the CELSS chamber facility. This design consists of a telescoping robot arm that slides vertically on a shaft positioned in the center of the CELSS chamber. The telescoping robot arm consists of a series of links which can be fully extended to a length equal to the radius of the working envelope of the CELSS chamber. The vertical motion of the robot arm is achieved through the use of a combination ball screw/ball spline actuator system. The robot arm rotates cylindrically about the vertical axis through use of a turntable bearing attached to a central mounting structure fitted to the actuator shaft. The shaft is installed in an overhead rail system allowing the entire structure to be stowed and deployed within the CELSS chamber. The overhead rail system is located above the chamber's upper lamps and extends to the center of the CELSS chamber. The mounting interface of the actuator shaft and rail system allows the entire actuator shaft to be detached and removed from the CELSS chamber. When the actuator shaft is deployed, it is held fixed at the bottom of the chamber by placing a square knob on the bottom of the shaft into a recessed square fitting in the bottom of the chamber floor. A support boot ensures the rigidity of the shaft. Three student teams combined into one group designed a model of the CELSS chamber robot that they could build. They investigated materials, availability, and strength in their design. After the model arm and stand were built, the class performed pre-tests on the entire system. A stability pre-test was used to determine whether the model robot arm would tip over on the stand when it was fully extended. Results showed the stand tipped when 50 Newtons were applied horizontally to the top of the vertical shaft while the arm was fully extended. This proved that it was stable. Another pre-test was the actuator slip test used to determine if there is an adequate coefficient of friction between the actuator drive wheels and drive cable to enable the actuator to fully extend and retract the arm. This pre-test revealed that the coefficient of friction was not large enough to prevent slippage. Sandpaper was glued to the drive wheel and this eliminated the slippage problem. The class preformed a fit test in the CELSS chamber to ensure that the completed robot arm is capable of reaching the entire working envelope. The robot was centered in the chamber and the arm was fully extended to the sides of the chamber. The arm was also able to retract to clear the drain pipes separating the upper and lower plant trays.

Davis, Mark↗

DOE OSTI2024

ResStock 2024.2 Dataset [Slides]

In the ResStock 2024.2 dataset, ResStock runs are used to create "what-if" scenarios including energy efficiency measures such as heat pumps, envelope improvements, and electrification of appliances. This dataset release includes 15 measure packages across two weather years and incorporates ResStock improvements in variable speed heat pump modeling, geothermal heat pump modeling, and housing characteristic data updates from RECS 2020.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

NASA NTRS1997

The New Heavy Gas Testing Capability in the NASA Langley Transonic Dynamics Tunnel

The NASA Langley Transonic Dynamics Tunnel (TDT) has provided a unique capability for aeroelastic testing for over thirty-five years. The facility has a rich history of significant contributions to the design of many United States commercial transports and military aircraft. The facility has many features which contribute to its uniqueness for aeroelasticity testing; however, perhaps the most important facility capability is the use of a heavy gas test medium to achieve higher test densities. Higher test medium densities substantially improve model building requirements and therefore simplify the fabrication process for building aeroelastically scaled wind-tunnel models. The heavy gas also provides other testing benefits, including reduction in the power requirements to operate the facility during testing. Unfortunately, the use of the original heavy gas has been curtailed due to environmental concerns. A new gas, referred to as R-134a, has been identified as a suitable replacement for the former TDT heavy gas. The TDT is currently undergoing a facility upgrade to allow testing in R-134a heavy gas. This replacement gas will result in an operational test envelope, model scaling advantages, and general testing capabilities similar to those available with the former TDT heavy gas. As such, the TDT is expected to remain a viable facility for aeroelasticity research and aircraft dynamic clearance testing well into the 21st century. This paper describes the anticipated advantages and facility calibration plans for the new heavy gas and briefly reviews several past test programs that exemplify the possible benefits of heavy gas testing.

Cole, Stanley R.↗

NASA NTRS2016

Feasibility of Varying Geo-Fence Around an Unmanned Aircraft Operation Based on Vehicle Performance and Wind

Managing trajectory separation is critical to ensuring accessibility, efficiency, and safety in the unmanned airspace. The notion of geo-fences is an emerging concept, where distance buffers enclose individual trajectories and areas of operation in order to manage the airspace. Currently, the Air Traffic Management system for commercial travel defines static distance buffers around the aircraft; however, commercial UASs are envisioned to operate in significantly closer proximity to other UAS requiring a geo-fence for spacing operations. The geo-fence size can be determined based on vehicle performance characteristics, state of the airspace, weather, and other unforeseen events such as emergency or disaster response. Calculation of the geo-fence size could be determined as part of pre-flight planning and during real-time operations. A largely non-homogeneous fleet of UASs will be operating in low altitude and will likely be commercially developed. Due to intellectual property concerns, the operators may not provide detailed specifications of the control system to UTM. In addition, the huge variety of UAS makes modeling each control system prohibitive and flight data for these vehicles may not exist. Therefore, a generalized, simple geo-fence sizing algorithm must be developed such that it does not rely on detailed knowledge of the vehicle control system, accounts for the presence of urban winds, and is sufficiently accurate. In this work, two simple models are investigated to determine its feasibility as an adequate means for calculating the geo-fence size. The vehicle data used in this work are provided by UAS manufactures who have partnered with NASA's UTM project and some publicly available websites. The first model utilizes wind data processed from the NOAA HRRR (Hourly Rapid Refresh) product and Sonar Annemometer data provided by San Jose State. The second model utilizes OpenFOAM which is a CFD code used to generate a wind field for flow around a single building. The key vehicle performance parameters can include UAS response time to disturbances, command to actuation latency, control system rate limits, time to recovery to desired path, and aerodynamics. It was found that the first model provides an initial understanding of geo-fence sizing, but does not provide enough accuracy to provide UTM with an efficient means of scheduling vehicles. The results of the second model reveal that modeling UAS controls systems with a linearized plant and gain scheduled PID controller does not allow capture the UAS flight dynamics within a significant envelope of the wind disturbances.

uncertainty↗

NASA NTRS1996

Computational Modeling of Ultrafast Pulse Propagation in Nonlinear Optical Materials

There is an emerging technology of photonic (or optoelectronic) integrated circuits (PICs or OEICs). In PICs, optical and electronic components are grown together on the same chip. rib build such devices and subsystems, one needs to model the entire chip. Accurate computer modeling of electromagnetic wave propagation in semiconductors is necessary for the successful development of PICs. More specifically, these computer codes would enable the modeling of such devices, including their subsystems, such as semiconductor lasers and semiconductor amplifiers in which there is femtosecond pulse propagation. Here, the computer simulations are made by solving the full vector, nonlinear, Maxwell's equations, coupled with the semiconductor Bloch equations, without any approximations. The carrier is retained in the description of the optical pulse, (i.e. the envelope approximation is not made in the Maxwell's equations), and the rotating wave approximation is not made in the Bloch equations. These coupled equations are solved to simulate the propagation of femtosecond optical pulses in semiconductor materials. The simulations describe the dynamics of the optical pulses, as well as the interband and intraband.

Goorjian, Peter M.↗

DOE OSTI2022

WBG-Enabled Current-Source Inverters for Integrated PM Motor Drives

This project takes advantage of the special capabilities of wide-bandgap (WBG) power semiconductor devices to develop innovative power electronics in the form of new current-source inverters (CSIs) that offer promising advantages over the dominant voltage-source inverter (VSI) topology. These CSIs, in turn, are extremely well-suited for integration into the housings of permanent magnet synchronous machines (PMSMs) to form integrated motor drives (IMDs). These new IMDs offer great promise for achieving major energy savings in a wide variety of applications that benefit from adjustable-speed control, including air conditioners, laundry appliances, industrial pumps/compressors, electric vehicles, and aerospace drives. WBG devices play a critical enabling role in these new IMDs because of their transformative features including much higher switching frequencies, lower losses, and compatibility with high operating temperatures. When incorporated into new CSI-based IMDs with PM machines, these WBG switches open the door to achieving major increases in power density, drive system efficiency, and fault tolerance, as well as substantial reductions in electromagnetic interference (EMI), manufacturing cost, and temperature-induced failures. The higher operating temperature capability of WBG devices compared to conventional silicon power devices is very appealing in IMD applications because the power electronics is mounted in close proximity to the motors which typically operate at temperatures well above the maximum limits of today’s silicon-based power electronics. This project has succeeded in designing, building, and testing multiple prototype versions of this CSI-IMD that have overcome many technical challenges in order to demonstrate the impressive performance improvements that can be achieved by the WBG-enabled CSI-IMD. The preliminary demo and bench-top versions of the current-source inverter developed during the first two years of the project were critical to laying the technical foundations for the 3 kW prototype CSI-IMD unit that was successfully built and tested during the third year. This prototype CSI-IMD unit was designed to fit within the housing envelope of the original permanent magnet (PM) synchronous machine in order to meet the demanding power density requirements that were set at the beginning of the project. All of the remaining performance objectives set for the prototype CSI-IMD unit including efficiency and electromagnetic interference (EMI) were also met. The last 18 months of the project were devoted to developing further enhancements of the WBG-enabled CSI-IMD technology that better prepare it for commercial production. More specifically, an upgraded version of the prototype CSI-IMD unit was developed that moved the power electronics into the same machine housing chamber as the motor, substantially raising the thermal demands on the power electronics. Tests with five different combinations of motor enclosure types and air cooling configurations were evaluated. Importantly, this work confirmed that the power electronics can deliver its full rated power and still operate well within its maximum temperature limits even for worst-case conditions when the housing is “totally-enclosed” without any openings for air to enter or exit the enclosure, and no blower/fan is provided to blow air over the outside surface of the enclosure. Reaching the full performance and energy-savings potential of this disruptive CSI-IMD motor drive technology is highly consistent with ARPA-E’s stated mission to “enhance the economic and energy security of the United States” while also supporting its commitment to “ensure that the U.S. maintains a technological lead in developing and deploying advanced energy technologies”. Follow-on projects are under way to explore the scalability of WBG-enabled CSI-IMD technology to 100 kW (peak) electric vehicle traction drives and fault-tolerant modular motor drives for future electrified aircraft propulsion applications.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2020

Gas phase formation of phenalene via 10π-aromatic, resonantly stabilized free radical intermediates

For the last few decades, the Hydrogen-Abstraction/aCetylene-Addition (HACA) mechanism has been fundamental in aiding our understanding of the source of polycyclic aromatic hydrocarbons (PAHs) in combustion processes and in circumstellar envelopes of carbon rich stars. However, the reaction mechanisms driving high temperature molecular mass growth beyond triphenylene (C 18 H 12 ) along with the link between PAHs and graphene-type nanostructures as identified in carbonaceous meteorites such as in Murchison and Allende has remained elusive. By exploring the reaction of the 1-naphthyl radical (C 10 H 7 ˙) with methylacetylene (CH 3 CCH) and allene (H 2 CCCH 2 ) under conditions prevalent in carbon-rich circumstellar environments and combustion systems, we provide compelling evidence on a facile formation of 1H-phenalene (C 13 H 10 ) – the central molecular building block of graphene-type nanostructures. Beyond PAHs, molecular mass growth processes from 1H-phenalene via ring-annulation through C3 molecular building blocks may ultimately lead to two-dimensional structures such as graphene nano flakes and after condensation of multiple layers to graphitized carbon. Furthermore, these fundamental reaction mechanisms are of crucial significance to facilitate an understanding of the origin and chemical evolution of carbon in our Galaxy.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

A dataset of eco-evidence tools to inform early-stage environmental impact assessments of hydropower development

The datasets described herein provide the foundation for a decision support prototype (DSP) toolkit aimed at assisting stakeholders in determining evidence of which aspects of river ecosystems have been impacted by hydropower. The DSP toolkit and its application are presented and described in the article “Evidence-based indicator approach to guide preliminary environmental impact assessments of hydropower development” [1]. Development of the DSP and the output for decision support centralize around 42 river function indicators describing the dimensionality of river ecosystems through six main categories: biota and biodiversity, water quality, hydrology, geomorphology, land cover, and river connectivity. Three main tools are represented in the DSP: A science-based questionnaire (SBQ), an environmental envelope model (EEM), and a river function linkage assessment tool (RFLAT). The SBQ is a structured survey-style questionnaire whose objective is to provide evidence of which indicators have been impacted by hydropower. Based on a global literature review, 140 questions were developed from general hypotheses regarding the impacts of dams on rivers. The EEM is a model to predict the likelihood of hydropower impacting indicators based on a several variables. The intended use of the EEM is for situations of new hydropower development where results of the SBQ are incomplete or highly uncertain. The EEM was developed through the compilation of a dataset containing attributes of dams, reservoirs, and geospatial information on environmental concerns, which was combined with data on ecological indicators documented at those sites through literature review. The model operates through 247 “envelopes” and weighting factors, representing the individual effect of each variable on each indicator, all available through spreadsheets. Finally, the RFLAT is a tool to examine causal relationships amongst indicators. Inter-indicator relationships were hypothesized based on literature review and summarized into node and edge datasets to represent the structure of a graphical network. Bayes theorem was used estimate conditional probabilities of inter-indicator relationships based on the output of the SBQ. Nodes and edges were imported into R programming environment to visualize ecological indicator networks. The datasets can be expanded upon and enriched with more detailed questions for the SBQ, building upon the EEM with to develop more sophisticated models, and identifying new relationships for the RFALT. Additionally, once the tools are applied to numerous hydropower developments, the output of the tools (e.g. evidence of impacted indicators) becomes a very useful dataset for meta-analyses of hydropower impacts.

13 HYDRO ENERGY↗

NASA NTRS1993

Spatial interpretation of NASA's Marshall Space Flight Center Payload Operations Control Center using virtual reality technology

In its search for higher level computer interfaces and more realistic electronic simulations for measurement and spatial analysis in human factors design, NASA at MSFC is evaluating the functionality of virtual reality (VR) technology. Virtual reality simulation generates a three dimensional environment in which the participant appears to be enveloped. It is a type of interactive simulation in which humans are not only involved, but included. Virtual reality technology is still in the experimental phase, but it appears to be the next logical step after computer aided three-dimensional animation in transferring the viewer from a passive to an active role in experiencing and evaluating an environment. There is great potential for using this new technology when designing environments for more successful interaction, both with the environment and with another participant in a remote location. At the University of North Carolina, a VR simulation of a the planned Sitterson Hall, revealed a flaw in the building's design that had not been observed during examination of the more traditional building plan simulation methods on paper and on computer aided design (CAD) work station. The virtual environment enables multiple participants in remote locations to come together and interact with one another and with the environment. Each participant is capable of seeing herself and the other participants and of interacting with them within the simulated environment.

Lindsey, Patricia F.↗

DOE OSTI2022

Decarbonization pathways for the residential sector in the United States

We report residential GHG emissions in the United States are driven in part by a housing stock where onsite fossil combustion is common, home sizes are large by international standards, energy efficiency potential is large and electricity generation in many regions is GHG intensive. In this analysis, we assess decarbonization pathways for the US residential sector to 2060, through 108 scenarios describing housing stock evolution, new housing characteristics, renovation levels and clean electricity. The lowest emission pathways involve very rapid decarbonization of electricity supply alongside extensive renovations to existing homes, including improving thermal envelopes and heat pump electrification of heating. Reducing the size and increasing the electrification of new homes provide further emission cuts and combining all strategies enables reductions of 91% between 2020 and 2050. The potential of individual mitigation strategies shows great regional variation. Reaching zero emissions will require simultaneous deployment of multiple strategies and greater reduction of embodied emissions.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

NASA NTRSDate not supplied

Extensibility of PICA TPS for Future Sample Return Missions

Stardust was the first successful robotic sample return mission delivering samples of the Comet Wild 2 to Earth in 2006. Genesis followed Stardust, in the era of “faster, better, cheaper,” collecting samples of solar wind. The Genesis sample return capsule (SRC) was larger and the program did not have the time nor funding to scale up the Stardust PICA heatshield and so, utilized an alternate heatshield. The successful Stardust mission led to future mission concepts baselining Stardust EDL, especially the entry heatshield. OSIRIS REx, was one such concept and the mission was designed to include build-to-print elements of the Stardust design. The primary scale-up limitation beyond Stardust and OSIRIS REx is the single-piece net cast PICA heatshield. In the past three years, FMI working with NASA Ames, expanded the manufacturing capability of PICA and demonstrated a 1.3 m PICA single piece TPS. This was done in anticipation of the Mars Sample Return mission as well as future Sample Return missions requiring larger-scale SRCs. This effort also identified a sustainable domestic replacement precursor for the PICA preform as the heritage precursor was discontinued in 2016 and FMI has gone through multiple rayon replacements since Stardust. As part of the effort, PICA was also tested at conditions higher than the Stardust or OSIRIS REx entry envelope to establish an expanded performance envelope and enable future sample return missions at higher entry speeds. The poster will highlight PICA sustainability and extensibility as part of the Sample Return to Earth session.

PICA thermal protection↗

DOE OSTI2024

On the Possibility of Installing the Rapid Cycling Synchrotron of the Electron Ion Collider in the AGS Tunnel

This report describes electron injector concepts for the Electron Ion Collider (EIC) using the tunnel of the Alternating Gradient Synchrotron (AGS) of Brookhaven National Laboratory which is to be compared to the RCS in the RHIC tunnel or a new ring in a new tunnel. Possible designs of the electron booster synchrotron, the Rapid Cycling Synchrotron (RCS) with good spin transparency with electron energies of up to 10 GeV and 18 GeV and placing the injector linac in the adjacent Building 912 for are worked out. The main reason for studying such options is the expectation that it will reduce the Electron Ion Collider injector cost because no civil construction is required, the machine is very compact, and existing infrastructure can be used. The design of an RCS with a top energy of 10 GeV with good spin transparency is quite conventional. However, for collider operation with 18 GeV electrons, this option would require accelerating the 10 GeV beam in the Electron Storage Ring (ESR) to 18 GeV and relying on the Sokolov Ternov self-polarization at 18 GeV in the ESR. Solutions for an RCS with Electron energies of up to 18 GeV with or without spin transparency are found to be possible but push the envelope of conventional magnet technology.

43 PARTICLE ACCELERATORS↗

NASA NTRS1987

Supersonic throughflow fans for high-speed aircraft

Increased need for more efficient long-range supersonic flight has revived interest in the supersonic throughflow fan as a possible component for advanced high-speed propulsion systems. A fan that can operate with supersonic inlet axial Mach numbers would reduce the inlet losses incurred in diffusing the flow from supersonic Mach numbers to a subsonic one at the fan face. In addition, the size and weight of an all-supersonic inlet will be substantially lower than those of a conventional inlet. However, the data base for components of this type is practically nonexistent. Therefore, in order to furnish the required information for assessing the potential for this type of fan, the NASA Lewis Research Center has begun a program to design, analyze, build, and test a fan stage that is capable of operating with supersonic axial velocities from inlet to exit. The objectives are to demonstrate the feasibility and potential of supersonic throughflow fans, to gain a fundamental understanding of the flow physics associated with such systems, and to develop an experimental data base for design and analysis code validation. A brief overview of past supersonic throughflow fan activities are provided; the technology needs discussed; the design of a supersonic throughflow fan stage, a facility inlet, and a downstream diffuser described; and the results from the analysis codes used in executing the design are presented. Also presented is an engine concept intended to permit establishing supersonic throughflow within the fan on the runway and maintaining the supersonic throughflow condition within the fan throughout the flight envelope.

Ball, Calvin L.↗