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- Xref: sparky sci.electronics:21038 sci.energy:6224 rec.autos.tech:16848
- Path: sparky!uunet!seismo!skadi!stead
- From: stead@skadi.CSS.GOV (Richard Stead)
- Newsgroups: sci.electronics,sci.energy,rec.autos.tech
- Subject: Re: Flywheel batteries as EV power source
- Message-ID: <51666@seismo.CSS.GOV>
- Date: 18 Dec 92 00:39:19 GMT
- References: <1992Dec13.114534.961@cmkrnl.com> <1992Dec15.004956.465@mtu.edu> <1992Dec17.205631.9731@u.washington.edu>
- Sender: usenet@seismo.CSS.GOV
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-
- In article <1992Dec17.205631.9731@u.washington.edu>, basiji@stein.u.washington.edu (David Basiji) writes:
- > The energy is being used to split the covalent bonds that hold the flywheel
- > together. In essence, you're separating charged atomic species and therefore
- > converting the kinetic energy of the rotor into potential energy in the
- > form of fragmented material. The idea of the housing is to allow the
- > rotor components enough time to interact with each other so that a large
- > fraction of the energy goes into rotor destruction rather than housing
- > destruction.
-
- What? Those covalent bonds aren't going to use up very much energy, it ain't
- hard to break them. In fact, breaking them likely has a net release of
- energy. Why do you think plastic gets hot when you stretch it? Part of the
- heat is the unrecoverable work you do on the bonds to stretch the material,
- and part is the release of energy after breaking the bonds. I've seen a
- dramatic demonstration of this by putting a thick polymer cable under tension.
- When it fails, it does so explosively and the material melts.
-
- The "time" you seem so interested in regarding the housing is meaningless.
- the particles are traveling so fast that they have a cratering interaction
- with the housing - they and the housing they impact will melt - there is
- no such thing as elastic collisions at these velocities. The idea of
- bits of rotor bouncing off the housing is a complete fallacy. The regime
- is one of melting and shock waves. The rotor is most likely completely
- destroyed by the time it interacts with the housing - the shock wave from
- the failure would likely melt it. The molten bits would still have
- hypervelocity, and still melt the housing.
-
-
- --
- Richard Stead
- Center for Seismic Studies
- Arlington, VA
- stead@seismo.css.gov
-