Mechanical & Fluid Systems

How to Make Low Flow Measurements Using Turbine Flow Meters

Accurate low flow measurement represents significant challenges in many applications. Some typical low flow applications in the aerospace market include: small UAV fuel consumption, satellite thruster fuel consumption, and fuel/chemical/water injection. The low dynamic energy associated with flow rates down to 0.001 GPM exceed the capabilities of most mechanical flow meters and force the use of less accurate flow meter technologies.

Posted in: White Papers, Instrumentation, Mechanical Components, Data Acquisition, Sensors

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Epoxy-based Hermetic Feedthroughs Boost Switchgear Reliability

With medium-voltage switchgear, progress is being made with regard to finding alternatives to SF6 as an insulation gas. Designs that incorporate dry air or a mixture of fluoroketone, nitrogen and oxygen as the insulating gas are being explored to minimize environmental impact.

Posted in: White Papers, Aerospace, Defense, Mechanical Components, Mechanics

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Jet Engine Exhaust Nozzle Flow Effector

Shape memory alloy provides variable shape control of aircraft structure through actively deformable surfaces.NASA’s Langley Research Center has created novel flow effector technology for separation control and enhanced mixing. The technology allows for variable shape control of aircraft structure through actively deformable surfaces. The flow effectors are made by embedding shape memory alloy actuator material in a composite structure. When thermally actuated, the flow effector deflects into or out of the flow in a prescribed manner to enhance mixing or induce separation for a variety of applications, including aeroacoustic noise reduction, drag reduction, and flight control. NASA developed the active flow effectors for noise reduction as an alternative to fixed-configuration effectors, such as static chevrons, that cannot be optimized for airframe installation effects or variable operating conditions, and cannot be retracted for off-design or failsafe conditions.

Posted in: Briefs, Aerospace, Aviation, Mechanics

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A Structural Joint with Multi-Axis Load Carrying Capacity

The technology can be used in aerospace and automotive applications, outdoor structures, and sporting goods.NASA’s Langley Research Center has developed a composite joint connector that is more structurally efficient than joints currently on the market. Traditionally, composite joints can bear heavy loads along their length but tend to fail when stress is applied along multiple axes. This joint is designed to minimize stress concentrations, leading to overall increased structural efficiency when compared to traditional joints.

Posted in: Briefs, Joining & Assembly, Mechanics

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Eddy-Current-Minimizing Flow Plug for Use in Flow Conditioning and Flow Metering

Innovators at NASA’s Marshall Space Flight Center have developed a suite of prototype fluid plug technologies with an array of capabilities for fluid flow metering, mixing, and conditioning. Each innovation within this suite is based upon a core technology that has no moving parts, is simple to manufacture, and provides high reliability and efficiency. Also, the base fluid plug technology can be modified with very few or no hardware changes to achieve the desired effect or combination of mixing, metering, and conditioning capabilities depending on the application.

Posted in: Briefs, Mechanical Components, Mechanics

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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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