NO moving parts?

[Ted Ledbetter <tedled at earthlink dot net>]

>An "engine" with NO moving parts sounds intriguing!    :-)
>
>I thought the deffinition of an "engine" was a device to
>convert energy into mechanical work, implying some
>sort of movement yes?
>
>I presume that these sound driven devices have a rotating
>shaft, but no other extraneous moving parts.  Is that right?
>
>Sounds too good!    :-)
>DG

"SOUND WAVES in "thermoacoustic" engines and refrigerators can 
REPLACE THE PISTONS  AND CRANKS that are typically built into 
such machinery"...(see below)

...whild searching the Los Alamos thermo-acoustic webpages:
http://www.lanl.gov/projects/thermoacoustics/
(which includes a downloadable thermo-acoustics text-book),
i followed a link to the thermoacoustic machine development 
website at Penn State University:
http://www.acs.psu.edu/thermoacoustics.html
which, (in addition to a description of it's academic research & thesis 
projects), also includes the following link to a special report published 
in American Scientist magazine:

October 2000
A summary article, "The Power of Sound," published by Penn State's Steve 
Garrett and Scott Backhaus from Los Alamos National Labs appears in the 
October 2000 issue of the American Scientist magazine..... This is a great 
article to read if you are newly interested in thermoacoustic machines....
(with absolutely great explanatory-diagram fig.s)...
http://www.sigmaxi.org/amsci/articles/00articles/Garrett.html

THE POWER OF SOUND

"Sound waves in "thermoacoustic" engines and refrigerators can replace the 
pistons and cranks that are typically built into such machinery

Steven L. Garrett and Scott Backhaus 

Abstract:
Over the past two decades, physicists and engineers have been working on a 
class of heat engines and compression-driven refrigerators that use no 
oscillating pistons, oil seals or lubricants. These so-called thermoacoustic 
devices take advantage of sound waves reverberating within them to convert 
a temperature differential into mechanical energy or mechanical energy into 
a temperature differential. Such machines can thus be used, for example, to
generate electricity or to provide refrigeration and air conditioning. Because 
thermoacoustic devices perform best with inert gases as the working fluid, 
they do not produce the harmful environmental effects such as global warming 
or stratospheric ozone depletion that have been associated with the engineered 
refrigerants such as CFCs and HFCs. Recent advances have boosted efficiencies 
to levels that rival what can be obtained from internal combustion engines, 
suggesting that commercial thermoacoustic devices may soon be commonplace."

...this AmericanScientist report includes several very good diagrams, including
eledctical and mechanical schematics and wave-phase plots...and, to me,
a most beautiful set of pix of a  simple solar-powered thermo-acoustic engine:
http://www.sigmaxi.org/amsci/articles/00articles/garrettcap3.html

just think..."Sonic-Heat" or "Hot-Sound" (not ColdFusion) electricity from
concentrated-sunlight, gas-fuel or wood-fire heat...just what i need for
my mountain-top dome-cabin...and to recharge my electric-bikes...