Today, I look a gift horse in the mouth. The
University of Houston's College of Engineering
presents this series about the machines that make
our civilization run, and the people whose
ingenuity created them.
I'm an honored guest in
Tokyo. I'm the only American at a national
workshop. The Japanese have been treating me like
visiting royalty. I've just given the keynote
address. Now I listen to talks in Japanese while an
interpreter whispers in my ear.
I'm here because of a homework problem I once
wrote. I asked students how much heat could
possibly be carried away by the boiling water in a
steam boiler. I asked them to count the molecules
leaving a water surface. Then they had to find how
much heat those molecules would carry.
The result says that boiling water can take as much
as 200 megawatts away from each square foot of
heater. That's far more than anyone thought
possible. So I went to the man who'd measured some
of the highest known cooling rates. I said, "Let's
write a paper about possibilities." He agreed. So
we showed that equipment could be cooled 200 times
better than it is cooled now.
The performance of a nuclear reactor or of a solar
tower is limited by the rate we can take energy
away from it. So is a computer. The more compact
the computer, the more waste energy has to be taken
out of its circuits. Improve heat removal in any of
these devices, and they'll perform far better.
The reviewers weren't crazy about our paper. It was
pretty simple for a technical journal. But they
agreed to publish it. After that, American
engineers took little notice of it.
But the Japanese said, "Here's a chance to
miniaturize and improve reactors, computers, and
much, much more." So now I sit in a darkened room
listening to the best thermal engineers in Japan.
They turn my simple idea around in the light of an
overhead projector, and it begins to sparkle. They
suggest a dozen ways to make possibility into
reality.
I watch the flickering graphs and ponder the myths
about Japanese imitation. This radio program has
shown me that creativity is a form of recognition.
Creative people see side roads that the rest of us
miss. Invention is not so much plucking an idea
from thin air as it is recognizing an idea out of
context. Next year the Japanese will make still
smaller and more efficient machines, and we'll
wonder why.
Andy Warhol has said that we'll each enjoy 15
minutes of fame during our lives. So I savor my
moment until my host interrupts. "Would I say a few
words at the reception?" That'll end the ceremony.
They'll have given the devil his due. Tomorrow,
these Japanese engineers will be back at work. It
has been a wonderful visit, but I can only hope the
next time I go to an idea session like this, it
will be in America.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.
(Theme music)
The paper that attracted Japanese attention is
Gambill, W.R. and J.H. Lienhard, An Upper Bound for
the Critical Boiling Heat Flux. Journal of
Heat Transfer. Vol. 111, No. 3, 1989, pp.
815-881.
Japanese development of the idea is described in
the following printed proceedings:
Researches of Boiling Heat Transfer: Recent
Development and Its Possibility, Heat
Transfer Society, Japan. (A national.
workshop organized by the Mechanical Engineering
Department at The University of Tokyo, July 20,
1990. ) See esp., 7 papers between pp. 60-96. (in
Japanese.)
I first proposed the theory behind the idea as a
homework problem in Tien, C.L. and Lienhard, J. H.,
Statistical Thermodynamics. Revised
ed. Washington, D.C.: Hemisphere, 1979, Problem
2.21, p. 55. I then solved it in Tien, C.L., and
Lienhard, J. H., Solutions Manual for
Statistical Thermodynamics. Washington,
D.C.: Hemisphere 1979, p. 13.
It turns out that the basic physics of the problem
had been fully discussed (without any reference to
high intensity process heat transfer) long before,
by
Schrage, R.W., A Theoretical Study of
Interphase Mass Transfer. New York: Columbia
University Press, 1953, Chapter II.
The limiting heat flux for water at atmospheric
pressure is a little over 200 megawatts per square
meter, as you can see in the figure below, taken
from the Gambill-Lienhard paper. At high pressure
it's roughly 20 times that value. It appears that
actual systems can be driven to about 1/10th of
these limits. That still gives a potential for heat
removal that is astonishingly high.
The Engines of Our Ingenuity is
Copyright © 1988-1997 by John H.
Lienhard.
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