Software

Two-Equation Turbulence Models for Application to Internal Flow Through Pneumatic Valves

Applications include design, analysis, and optimization of valves and pumps. John F. Kennedy Space Center, Florida Predicting turbulent flowfield and pressure drop in complex internal flows, such as valves, pumps, and turbines, is of great interest in many areas of technology. Accurate prediction of three-dimensional (3D) flowfield in complex devices is critically dependent on the accuracy of the turbulence model used to describe the turbulence energy production and dissipation processes within the flowfield region of interest.

Posted in: Mechanical Components, Software, Briefs

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Multi-Species Turbulent Mixing Under Supercritical-Pressure Conditions

This mixing model under high-pressure conditions would be useful for automotive, gas turbine engine, and liquid rocket engine companies. NASA’s Jet Propulsion Laboratory, Pasadena, California A model describing supercritical-pressure, multi-species turbulent mixing has been developed to simulate situations prevailing in diesel, gas turbine, and HCCI (homogeneous charge compression ignition) engines. It is also a situation occurring in atmospheric planetary science, such as the Venus atmosphere. Previously, there had been no model to describe this high-pressure mixing under turbulent conditions.

Posted in: Materials, Software, Briefs

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A Model of Reduced Oxidation Kinetics Using Constituents and Species

The advantage of such a simple model becomes increasingly significant with increasing carbon atoms of the fuel. NASA’s Jet Propulsion Laboratory, Pasadena, California Elementary-reaction chemical kinetics of hydrocarbon oxidation consists of hundreds to thousands of species and thousands of reactions. As such, it is impossible to use it in models and codes involving turbulence because computations are unfeasible due to lack of memory and computer speed. The solution is to reduce the elementary chemical kinetics to a much smaller set of representative reactions. A kinetic reduction has been shown to work very well for isooctane and its mixtures with n-pentane, iso-hexane, and n-heptane.

Posted in: Materials, Software, Briefs

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Determining Radiation Shielding Capability of the Earth’s Atmosphere from FAA Radiation Data

An algorithm is used to determine how much material is needed to shield astronauts on their trip to Mars. John F. Kennedy Space Center, Florida The FAA, using its CARI-6 program, provides galactic cosmic radiation dosage rates for any location on the Earth from ground up to 60,000 ft (≈18,300 m). One way to protect astronauts from galactic cosmic radiation (GCR) on a Mars mission is to use material shielding. However, current radiation shielding code does not model shields thicker than about 100 to 200 gm/cm2, and it has been shown that this shield thickness is insufficient to provide protection for a trip to Mars. There is effort underway to extend the code to thicker shields, but there is a lack of experimental data to use to verify the code. The atmosphere represents a very thick and effective radiation shield, and that atmospheric radiation data might be used as a source of verification data.

Posted in: Materials, Software, Briefs

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Integrated Space Weather Analysis System (iSWA)

Goddard Space Flight Center, Greenbelt, Maryland The iSWA system is a Web-based dissemination framework for NASA-relevant space weather information that combines forecasts based on the most advanced space weather models with concurrent space environment information. A key design driver for the iSWA system is to generate and present vast amounts of space weather resources in an intuitive, user-configurable, and adaptable format, enabling users to respond to current and future space weather impacts, as well as enabling post-impact analysis.

Posted in: Physical Sciences, Software, Briefs

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Automatic Localization of MSL Rover Mosaics in HiRISE Imagery

Applications include localization of autonomous vehicles in GPS-denied environments for military applications. NASA’s Jet Propulsion Laboratory, Pasadena, California Mars Science Laboratory (MSL) surface operations require precise and accurate knowledge of rover position. A key means of establishing/verifying position is to match ortho-rectified mosaics from the MSL onboard cameras to orbital data. Manual localization by matching mosaics to HiRISE imagery can be laborious and somewhat subjective. Ortho-rectified mosaics and orbital images differ dramatically in appearance, due to the extreme viewpoint change as well as occlusions (i.e. objects must be in line of sight) in the mosaics. A straightforward intensity-based matcher using correlation or local feature descriptors cannot cope with this difference. Instead, an information theoretic matcher was used that measures the mutual information between the mosaic and trial positions in the HiRISE imagery.

Posted in: Physical Sciences, Software, Briefs

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SAM/MSL Terrestrial Background Spectral Library

Goddard Space Flight Center, Greenbelt, Maryland The SAM/MSL Terrestrial Background Spectral Library is one of the tools developed for identifying known terrestrial background for the Mars Science Laboratory (MSL) Sample Analysis at Mars (SAM) mission. The SAM instrument suite can detect trace elements in the ppb range and therefore requires a robust library and informational structure to aid it in identification of source origin. It is unique in that it is the first spectral library developed containing spectra of more than 800 gas chromatography mass spectrometry (GCMS) files generated from analysis of actual rover materials. The terrestrial background library will help ensure that the spectral identifications remain accurate, and also determine whether the spectra arise from the Mars or Earth environment.

Posted in: Physical Sciences, Software, Briefs

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