Keyword: External combustion engines

Briefs: Energy

Innovators at NASA’s Glenn Research Center have developed two novel technologies that make Stirling engines more efficient and less costly. First, Glenn’s thermoacoustic power converter uses sound to turn heat into...

Briefs: Mechanical & Fluid Systems
Mechanisms for Achieving Non-Sinusoidal Waveforms on Stirling Engines

The current state-of-the-art Stirling engines use sinusoidal piston and displacer motion to drive the thermodynamic cycle and produce power. Research performed at NASA Glenn has shown that non-sinusoidal waveforms have the potential to increase Stirling engine power density,...

Briefs: Mechanical & Fluid Systems
Improving Stirling Engine Performance Through Optimized Piston and Displacer Motion

Stirling engines typically achieve high efficiency, but lack power density. Low power density prevents them from being used in many applications where internal combustion engines are viable competitors, and increases system costs in applications that require...

Briefs: Energy

Power generation from an external or internal heat source using thermal energy conversion technologies such as solid-state thermionics and thermoelectrics or dynamic conversion...

Briefs: Robotics, Automation & Control
Magnetostrictive Alternator

This innovation replaces the linear alternator presently used in Stirling engines with a continuous-gradient, impedance-matched, oscillating magnetostrictive transducer that eliminates all moving parts via compression, maintains high efficiency, costs less to manufacture, reduces mass, and eliminates the need for a...

Briefs: Mechanical & Fluid Systems
Cascading Tesla Oscillating Flow Diode for Stirling Engine Gas Bearings

Replacing the mechanical check-valve in a Stirling engine with a micromachined, non-moving-part flow diode eliminates moving parts and reduces the risk of microparticle clogging.

Briefs: Medical

A proposed special-purpose infrared imaging system would be a compact, portable, less-expensive alternative to functional magnetic resonance imaging (fMRI) systems heretofore used to study...

Briefs: Physical Sciences

The device illustrated in Figure 1 is designed primarily for use as a regenerative heat exchanger in a miniature Stirling engine or Stirling-cycle heat pump. A regenerative heat exchanger (sometimes...

Briefs: Physical Sciences

A proposed thermoelectric device would exploit natural temperature differences between air and soil to harvest small amounts of electric energy. Because the air/soil temperature difference...

Briefs: Mechanical & Fluid Systems

Experiments have shown that an assembly of multiple free-piston Stirling engines can be designed and constructed in such a way as to both (1) make the vibrations of the engines...

Briefs: Mechanical & Fluid Systems

An important secondary topic addressed in the research and development effort described in the preceding article is the use of artificial neural networks to improve the monitoring...

Briefs: Materials

A prototype Stirling-engine regenerator containing a matrix made of carbon-fiber-based composite materials has been developed. The concept underlying this development effort is one of...

Briefs: Physical Sciences

The figure illustrates an apparatus for measuring heat-transfer and pressure-drop characteristics of porous plug specimens in oscillating flows. The apparatus is built around an...

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