[IP] A traveling-wave engine to power deep space travel
Begin forwarded message:
From: Kurt Albershardt <kurt@xxxxxx>
Date: October 4, 2004 11:54:28 AM EDT
To: dave@xxxxxxxxxx
Subject: A traveling-wave engine to power deep space travel
LOS ALAMOS, N.M., Sept. 16, 2004 -- A University of California
scientist working at Los Alamos National Laboratory and researchers
from Northrop Grumman Space Technology have developed a novel method
for generating electrical power for deep-space travel using sound
waves. The traveling-wave thermoacoustic electric generator has the
potential to power space probes to the furthest reaches of the
Universe.
In research reported in a recent issue of the journal Applied Physics
Letters, Laboratory scientist Scott Backhaus and his Northrop Grumman
colleagues, Emanuel Tward and Mike Petach, describe the design of a
thermoacoustic system for the generation of electricity aboard
spacecraft. The traveling-wave engine/linear alternator system is
similar to the current thermoelectric generators in that it uses heat
from the decay of a radioactive fuel to generate electricity, but is
more than twice as efficient.
The new design is an improvement over current thermoelectric devices
used for the generation of electricity aboard spacecraft. Such devices
convert only 7 percent of the heat source energy into electricity. The
traveling-wave engine converts 18 percent of the heat source energy
into electricity. Since the only moving component in the device besides
the helium gas itself is an ambient temperature piston, the device
possesses the kind of high-reliability required of deep space probes.
The traveling-wave engine is a modern-day adaptation of the 19th
century thermodynamic invention of Robert Stirling -- the Stirling
engine -- which is similar to a steam engine, but uses heated air
instead of steam to drive a piston. The traveling-wave engine works by
sending helium gas through a stack of 322 stainless-steel wire-mesh
discs called a regenerator. The regenerator is connected to a heat
source and a heat sink that causes the helium to expand and contract.
This expansion and contraction creates powerful sound waves -- in much
the same way that lightning in the atmosphere causes the thermal
expansion that produces thunder. These oscillating sound waves in the
traveling-wave engine drive the piston of a linear alternator that
generates electricity.
NASA funded the traveling-wave thermoacoustic electric generator
research.
Los Alamos National Laboratory is operated by the University of
California for the National Nuclear Security Administration (NNSA) of
the U.S. Department of Energy and works in partnership with NNSA's
Sandia and Lawrence Livermore national laboratories to support NNSA in
its mission.
Los Alamos enhances global security by ensuring the safety and
reliability of the U.S. nuclear deterrent, developing technologies to
reduce threats from weapons of mass destruction, and solving problems
related to defense, energy, environment, infrastructure, health and
national security concerns.
<http://www.lanl.gov/worldview/news/releases/archive/04-078.shtml>
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