Tech Briefs

Process for Forming a High-Temperature Single Crystal Preloader

Non-contacting, acoustic pressure seals and preloader superalloys prevent fluid leakage.Friction has long been a thorny problem for sealing-device designers. Traditional sealing devices rely on a contacting relationship between surfaces and sealing elements to prevent fluid leakage, but in the case of moving elements, this contact produces friction that causes wearing and eventual failure of the sealing system. Friction also consumes energy and produces harmful debris. In a new breakthrough, however, researchers at NASA’s Glenn Research Center have patented an acoustic seal that generates a pressure barrier to prevent fluid leakage from a high-pressure area. Instead of using contacting components as a seal, the patented seal employs acoustic technology to generate pressure waves that control, mitigate, or prevent fluid leakage. The result is a very low-leakage, non-contact seal that eliminates problems associated with friction. In addition, when traditional seals are needed in extremely high-temperature environments, Glenn innovators have developed new processes to enable the fabrication of single-crystal superalloys that can increase the upper limit of thermal seals to greater than 2000 °F.

Posted in: Briefs, Mechanical Components, Mechanics, Fluid Handling

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Compact Vibration Damper

Applications include wind tunnel models, launch vehicles, smokestacks, helicopters, wind turbines, and skyscrapers.NASA’s Langley Research Center has developed a compact tuned damper to reduce vibration occurring at a fixed frequency. Tuned dampers reduce vibration of the base structure by the dissipation of energy. The magnitude of the dissipated energy is proportional to the square of the displacement or velocity of the tuned mass, which in turn is proportional to the range of motion. The NASA damper design allows the slider mass to achieve 2× to 3× greater range of motion than that found in conventional devices. This enables 4× to 9× more effectiveness for the same size and weight; or the same effectiveness for a 4× to 9× decrease in weight. The damper is also tunable and can be adjusted in effectiveness. The damper can be made small enough for use in wind tunnel tests, or scaled up to large sizes like those used in helicopters, wind turbines, or skyscrapers.

Posted in: Briefs, Mechanical Components, Mechanics

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Fluidic Oscillator Array for Synchronized Oscillating Jet Generation

This technology can be used in aerospace applications, shipbuilding, gas turbines, and commercial spa equipment.NASA’s Langley Research Center develops innovative technologies to control fluid flow in ways that will ultimately result in improved performance and fuel efficiency. Often called fluidic oscillators, sweeping jet actuators, or flip flop oscillators, these flow-control devices work based on the Coanda effect. They can be embedded directly into a control surface (such as a wing or a turbine blade) and generate spatially oscillating bursts (or jets) of fluid to improve flow characteristics by enhancing lift, reducing drag, or enhancing heat transfer. Recent studies show up to a 60% performance enhancement with oscillators. NASA offers two new fluidic oscillator designs that address two key limitations of these oscillators: coupled frequency-amplitude and random oscillations. One oscillator effectively decouples the oscillation frequency from the amplitude. The other design enables synchronization of an entire array. The new oscillators have no moving parts — oscillation, decoupling, and synchronization are achieved entirely via internal flow dynamics.

Posted in: Briefs, Mechanical Components, Mechanics, Fluid Handling

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Magnetostrictive Pressure Regulating System

The regulator system offers precise operation with response times up to an order of magnitude faster than current technologies.NASA’s Marshall Space Flight Center has developed a set of unique magnetostrictive (MS) technologies for utilization in pressure regulation and valve systems. By combining MS-based sensors with a newly designed MS-based valve, Marshall has developed an advanced MS regulator. This innovative approach provides both a regulator and a valve with rapid response times. In addition, the components are lightweight, compact, highly precise, and can operate over a wide range of temperatures and pressures. A prototype of the MS valve has been developed and NASA is seeking partners for licensure of this novel technology.

Posted in: Briefs, Instrumentation

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Shape Sensing Using a Multi-Core Optical Fiber Having an Arbitrary Initial Shape in the Presence of Extrinsic Forces

This technology can be used for aerospace safety, medical applications, robotics, and space exploration.NASA’s Langley Research Center has demonstrated a patent-pending method and apparatus for determining the position, in three dimensions, of any point on an optical fiber. The new method uses low-reflectance Fiber Bragg Grating (FBG) strain sensors in a multicore fiber to determine how any point along that fiber is positioned in space. The characteristics of optical fibers and the FBGs vary with curvature, and by sensing the relative change of FBGs in each of three or more fiber cores, the three-dimensional change in position can be determined. By using this method in monitoring applications where optical fibers can be deployed — such as in structures, medical devices, or robotics — precise deflection, end position, and location can be determined in near real time. This innovative position detection method offers 10 times greater positional accuracy than comparable optical techniques.

Posted in: Briefs, Instrumentation

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Magnetic and Raman-Based Method for Process Control During Fabrication of Carbon-Nanotube-Based Structures

The methodology enables high quality and high yield with about 30% weight reduction over carbon composite materials.NASA’s Langley Research Center has developed an innovative magnetic and Raman-based method for macroscopic process control during fabrication of carbon-nanotube-based structures. The development of super-strong, lightweight materials based on carbon nanotubes promises new materials with the strength of current carbon composite materials, but at substantially less weight. The development of these new materials is dependent upon nanotube quality, alignment, and load transfer between individual nanotubes in the structure. However, current fabrication process controls are limited to time-consuming microscopy testing at intermittent stages during processing. NASA’s innovative method can be applied during nanotube structure fabrication to obtain real-time feedback on critical processing parameters during fabrication. Moreover, the method is compatible with in-line fabrication processes.

Posted in: Briefs, Instrumentation

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Fully Premixed, Low-Emission, High-Pressure, Multi-Fuel Burner

Applications include use in aircraft, spacecraft, and heating and boilers for commercial and residential systems.NASA’s Glenn Research Center has developed a novel design for a fully premixed, high-pressure burner capable of operating on a variety of gaseous fuels and oxidizers, including hydrogen-air mixtures, with a low pressure drop. The burner provides a rapidly and uniformly mixed fuel-oxidizer mixture that is suitable for use in a fully premixed combustion regime that has the benefits of low pollutant emissions (when operated at fuel lean conditions) and freedom from harmful flashback effects, combustion instabilities, and thermal meltdown problems that are normally associated with premixed combustion systems operating at high pressures.

Posted in: Briefs, Aerospace, Aviation, Energy

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