Tech Briefs

High-Channel-Count, High-Scan-Rate Data Acquisition System for the NASA Langley Transonic Dynamics Tunnel

Langley Research Center, Hampton, Virginia The NASA Langley Research Center (LaRC) Transonic Dynamics Tunnel (TDT) has been operational since 1960, investigating a wide range of aeroelastic and non-aeroelastic phenomena. A dedicated aeroelastic test facility, the TDT is a large, variable-pressure, transonic wind tunnel. To support unique types of aeroelastic and dynamic tests, the TDT possesses a dynamic data acquisition system (DAS) with synchronous scanning of all analog channels. Steady (static) values are simply computed as the mean of any signal. The existing TDT DAS is referred to as the Open Architecture Data Acquisition System (OA-DAS). An effort was initiated to replace OA-DAS in order to increase the scan rate, increase the channel count, increase the reliability, increase user friendliness, and improve upon some features while maintaining synchronous scanning and other unique abilities. This effort has been spearheaded by researchers within the Aeroelasticity Branch (AB) co-located with the TDT; hence, the new data system has been named AB-DAS. The new data system will serve as the primary data system and will substantially increase the scan rate capabilities and analog channel count. This synchronous and dynamic system enables high-channel-count buffet and aeroacoustic tests in addition to the range of other testing done at TDT.

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Fusible Alloy Thermometer

Goddard Space Flight Center, Greenbelt, Maryland This work was based on the need for a relatively small passive detector of maximum temperature reached by an object that can be visually inspected. The device requirements are to be hermetically sealed for contamination control, give a clear indication of maximum temperature achieved (non-reversible) with a ~10 °C resolution, have an essentially unlimited shelf-life and insensitivity to radiation, be passive without any electronics or mechanisms, provide good thermal conductivity, and be low-cost. Prior detectors have an unclear lifetime, contamination outgassing properties, and radiation tolerance. These could be used at much higher temperatures than plastic methods (>>100 °C), though out of scope for the tests performed to date.

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Small-Volume Pressurized Sample Handling System

NASA’s Jet Propulsion Laboratory, Pasadena, California A method was developed for effective, efficient, non-destructive, in-situ sample processing. Pressure vessels are used for sample delivery and collection, a shaker is used to keep the particles suspended, a back pressure of argon gas is used to keep the system under pressure to regulate the flow, and flow restrictors and frits are used that never come into contact with the sample slurry to avoid clogs.

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Generation-2 Lean Direction Injection System

This technology eliminates the risk of flashback and auto-ignition, and achieves emission and operability goals. John H. Glenn Research Center, Cleveland, Ohio An advanced Lean-Direct-Injection (LDI) turbine engine combustor was developed. Named LDI-II, which stands for second-generation LDI, this technology has vastly improved and expanded the performance characteristics of the initial LDI design by not only exceeding NASA’s N+2 emissions goal, but also meeting the operability requirements of full engine power range. The key enabling feature of the technology is the coherence combination of fuel staging and positioning/sizing of swirler-venturi fuel/air mixer elements.

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Testing Aircraft Electric Propulsion Systems on NASA’s Modular Stand

This test stand allows the aviation industry to test a wide range of electric propulsion systems to understand efficiencies and identify needed design improvements. Armstrong Flight Research Center, Edwards, California As powered flight expands to include electric propulsion technologies, aeronautics designers need to understand the electrical, aerodynamic, and structural characteristics of these systems. Therefore, researchers at NASA’s Armstrong Flight Research Center have developed a modular test stand to conduct extensive measurements for efficiency and performance of electric propulsion systems up to 100 kW in scale.

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Iodine-Compatible Hall Effect Thruster

The use of iodine reduces the technical demands on thruster design. Marshall Space Flight Center, Alabama Iodine-compatible Hall effect thruster. The Hall effect thruster (HET) was designed for long-duration operation with gaseous iodine as the propellant. Iodine is an alternative to the state-of-the-art propellant xenon. Compared to xenon, iodine stores as a solid at much higher density and at a much lower pressure. Because iodine is a halogen, it is reactive with some of the materials with which a Hall thruster is typically constructed. Through research and testing, the new method allows for the HET to be used with iodine propellant for long periods of time.

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Burnable-Poison-Operated Reactor Using Gadolinium Loaded Alloy

Marshall Space Flight Center, Alabama The problem to be resolved in this work was the use of radial control drums as the sole active reactivity control system for nuclear thermal propulsion, which results in significant rocket performance changes during full-power operation. This can result in large inefficiencies in propellant usage, inaccurate estimations in Isp and thrust, and can be a dangerous operation requiring continuous active control of the reactor given the unstable nature of current nuclear thermal rocket reactor designs.

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