Dynamic Aero-Shroud Oscillating Jet

Rebecca Farr, Endwell Daso, Victor Pritchett, and Dr. Ten-See Wang, NASA Marshall Space Flight Center, Huntsville, AL

Applying supersonic counter-flowing cold gas jets of a certain mass flow rate and pressure at the nose of a supersonic vehicle can reduce drag and aerodynamic heating, and possibly reshape sonic boom signatures.

This technology will enable new flight vehicle concepts and applications of supersonic and hypersonic flight. While previous work done with high-energy counter-flowing plasma jets has historically shown limited practicality or effectiveness, this lowenergy cold gas jet concept leverages a previously unknown aspect of natural aerodynamics: momentum transfer and shock dispersion, as demonstrated in wind tunnel testing. These effects have been shown to reduce aerodynamic heating of the body, and it is possible that drag is reduced as well.

“I feel fortunate to have worked with my team members, who are all dedicated technical experts in their own right. I hope this publicity will help our team get some significant funding in order to design more test and analysis, and ultimately to conduct prototype testing for actual applications.” (Dr. Ten-See Wang)

This patent-pending cold gas delivery system and closed-loop control technology may also be used to counteract forcing functions caused by wind gust loads and vehicle-generated oscillations. This concept does not alter the outer mold line of the vehicle, and it is activated and modulated in flight only as needed. For airbreathing vehicles, the jets could be continuously fed by external atmosphere, collected at engine inlets, for example.

This work has the potential to enable radical improvements in supersonic aircraft performance and efficiency, lower thermal protection system mass due to moderated aero-thermal environments, and reduce sonic boom signatures at the ground. It may also provide a quieter ride for passengers by providing a means to actively counteract aerostructural dynamic flutter and noise in flight.

This concept will enable hypersonic, suborbital passenger transports that connect the cities of Earth, allowing passengers to travel great distances in very short times; for instance, from New York to Sydney, Australia, in less than three hours.

For more information, visit http://contest.techbriefs.com/component/content/article/1783 .

Honorable Mentions

Variable Valve Lift System for Internal Combustion Engines

Luigi Conti, Torino, Italy

This invention is an electronically controllable Variable Valve Lift System for internal combustion engines. It is a mechanical transmission having the capability of varying the lift of the intake and/or exhaust poppet valves while the engine is running, and when varying its working conditions. The mechanical transmission includes a regulator mechanism (RM) with two slotted holes, and an actuation mechanism. The regulator mechanism is operated by a suitable system (e.g. an electric engine driving a worm gear) in order to modify the angular position of the slotted holes and the movement of the slider when the cam is lifting, with respect to the two oscillating levers, actuating the variation of the transmission characteristic from the cam to the poppet valve.

For more information, visit http://contest.techbriefs.com/component/content/article/1874 .

Precise Control of Variable Pitch Propeller

Paul Baker, Denham Springs, LA

Currently, propeller pitch control uses three approaches: hydrolic oil pressure, mechanical control using lateral motion along the axis of the drive shaft, or electric motor control with the drive motor embedded in the hub. The Angular Motion Translator (AMT) is a mirrored planetary gear system that allows the angular relationship between two nonrotating parts to be translated into an identical angular relationship between two rotating parts, all with a direct, geartooth-to-geartooth mechanical connection.

When applied as an integral component of a propeller hub, the AMT allows for precise, directly mechanical control of blade pitch. Additionally, since all contact is either through gearteeth or ball bearings, the wear rates will be no more than that of a standard gearbox.

For more information, visit http://contest.techbriefs.com/component/content/article/1389 .

NASA Tech Briefs Magazine

This article first appeared in the November, 2011 issue of NASA Tech Briefs Magazine.

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