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PIV Measurements of a Low-noise Top-mounted Propulsion Installation for a Supersonic Airliner
Get PDFA model-scale exhaust system was tested to validate low-noise propulsion concepts and noise prediction methods. The tests involved far-field acoustics, phased array, and particle image velocimetry (PIV). This paper covers the particle image velocimetry portion. Data was acquired at NASA Glenn's Aero-Acoustic Propulsion Lab for a series of nozzles with different chevron designs, both uninstalled and installed on a representative aircraft planform. The impact of the various chevron treatments on the turbulent velocity field was documented, along with the impact of the pylon and planform. When correlated with far-field acoustic measurements and phased array measurements, reported in companion papers, the explanation of acoustic benefits from top-mounted propulsion is clear as is the path toward optimization of the concept
Evaluation of Full Reynolds Stress Turbulence Models in FUN3D for Axisymmetric Jet Flow
Get PDFTwo full seven-equation turbulence models have been implemented into the FUN3D code to evaluate their ability to improve the computation of challenging flows encountered in aerospace propulsion, including mixing flows. These models are the SSG/LRR and Wilcox full second-moment Reynolds stress models. They solve equations for the six components of the Reynolds stress and a seventh equation for the mixing length. Two standard eddy viscosity models are also evaluated for comparison, the Spalart-Allmaras (SA) one-equation model and the Menter Shear Stress Transport (SST-V) two-equation turbulence model. Flow through an axisymmetric reference nozzle is examined at three flow conditions: subsonic unheated, subsonic heated, and near sonic unheated. Centerline profiles of velocity and turbulent kinetic energy and radial profiles of velocity, turbulent kinetic energy and turbulent stresses are examined. characteristics, no significant changes in the downstream flow behavior compared to the baseline case are observed. Furthermore, the total power consumed by the fans for different incoming flow conditions also remain marginally the same. It is hoped that the results, albeit obtained at very low speeds. would serve as a database for this technologically interesting flow field that has not been explored adequately before
Load Flow Analysis with Analytic Derivatives for Electric Aircraft Design Optimization
Get PDFMany of the aircraft concepts of the future are exploring the use of hybrid-, turbo- or all-electric propulsion systems to improve performance and decrease environmental impacts. These aircraft concepts range from small rotorcraft for urban air mobility to conventional commercial transports to large blended wing body designs. Developing the conceptual design for these vehicles presents a challenge, however, as traditional aircraft design tools often were not developed to handle these unique propulsion system architectures. Previous studies on these vehicles have therefore relied on relatively simple models of the electrical transmission and distribution system. This paper presents the development of a hybrid AC-DC load flow (or power flow) analysis capability to enhance the conceptual design of these concept vehicles. Specifically, the desire was to create a load flow analysis capability within the OpenMDAO framework that is also being used to develop a set of compatible tools for rapid optimization of conceptual designs. This load flow analysis capability is unique in its flexible object-oriented structure and implementation of analytic derivatives to facilitate the use of solvers and gradient based optimization in the design process. The developed hybrid load flow analysis capability is first verified against a published 13-bus example then used to model the electrical distribution system for a turbo-electric tiltwing aircraft
Boarding Pass: InSight Lander Mission to Mars
Get PDFJoin us on a journey from Integration and Test through to launch and landing on Mars for the Mars InSight Lander. InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) launched from Vandenberg Air Force Base in California on May 5, 2018 at 4:05 AM and landed on Mars on November 26, 2018 in Elysium Planitia. InSight was the first planetary launch from the West Coast and is the first Mars mission to attempt to measure Marsquakes. InSight is also poised to measure the thermal properties of Mars' interior and the planet's wobble. Enjoy an amazing photographic journey into the inner workings of life before launch and at landing on Mars
Implementation of Cross-Agency Nuclear Applications
Get PDFThe Radioisotope Power System (RPS) Program was established in 2009 to manage RPS investments for NASA to ensure the availability of RPS for the exploration of the solar system in environments where conventional solar or chemical power generation is impractical or impossible. The RPS Program is a multi-center and multi-agency program. NASA is in partnership with the Department of Energy (DOE) Office of Nuclear Energy to provide technologically robust nuclear power system solutions to robotic spacecraft and exploration missions. During the last decade, the RPS Program and DOE have supported missions, developed technologies and initiated new power system developments. These technical areas, as all technical areas, have challenges and standard engineering solutions; however, clearing the path to enable the technical work requires agreements to be established. This paper describes a process by which two governmental agencies have established a successful basis to accomplish the needed work
Converging-Diverging Nozzle Thruster Code for Nuclear or Chemical Rocket Performance Computations
Get PDFThis report describes development of a variable area ratio C-D nozzle numerical computational code "THRST", applicable to the evaluation of nuclear or chemical rocket performance. The propellant for the nuclear rockets is para-hydrogen with gas properties supplied by a sub-routine, while properties for chemical thrusters need to be user input. Detailed documentation of input and output variables and sample output listings enable the report to function as a "User Manual"
TESS Data Release Notes: Sectors 1 & 2, Multi-Sector 1-2, DR3
Get PDFThis release note discusses the planetary transit search data products produced by the Science Processing Operations Center at Ames Research Center from Sectors 1-2 observations made with the TESS (Transiting Exoplanet Survey Satellite) spacecraft and cameras as a means to document instrument performance and data characteristics
Heatshield for Extreme Entry Environment Technology (HEEET) TPS for Ice Giants Probe Missions
Get PDFThis poster provides an overview of the requirements, design, development and testing of the 3D Woven TPS being developed under NASAs Heatshield for Extreme Entry Environment Technology (HEEET) project. Under this current program, NASA is working to develop a Thermal Protection System (TPS) capable of surviving entry into Saturn. A primary goal of the project is to build and test an Engineering Test Unit (ETU) to establish a Technical Readiness Level (TRL) of 6 for this technology by 2018. Poster also discusses use of HEEET TPS for probe missions to the Ice Giants, Uranus and Neptune