Re: On Superconductors, Superfluids and Heat Transfer
From: greywolf42 (mingstb_at_marssim-ss.com)
Date: 01/03/05
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Date: Mon, 03 Jan 2005 22:03:51 GMT
TC <tclarke@ist.ucf.edu> wrote in message
news:1104726006.266322.124530@f14g2000cwb.googlegroups.com...
Thomas. Your new posting software is interfering with the autoreply
attribution marking. I prefer the prior version.
> "greywolf42" <mingstb@marssim-ss.com> wrote in message
> >Thomas Clarke <tclarke@ist.ucf.edu> wrote in message
{snip content-free repartee}
> > > My mechanism is advection currents caused by
> > > (incipient) temperature differences.
>
> > Please provide a reference to the physics text or theory or other
> > source that supports you claim that this occurs. The giveaway is
> > the parenthetic "incipient." Advection/convection currents
> > require a temperature difference to form.
>
> I included the "incipient" because of transitory, start-up effects.
Avoidance. Transitory and/or startup has nothing to do with normal thermal
conductivity -- which requires two *different* temperatures.
------------------------
Throughout the following post, Thomas can't seem to decide what property he
wants to claim or address. He dances between the terms "infinite thermal
conductivity", "superconductor of heat", and "perfect thermal conductor."
Sometimes he uses the word "transfer" instead of "conductor" or
"conductivity." Whenever he is pinned down on any one argument, he switches
terms -- and claims that it is *my* fault for misunderstanding.
{I'm also enforcing my personal ban on Thomas' attempt to rely upon
analogies between superconductivity of heat and electrical superconductors.}
------------------------
(A)
> "...a superfluid is also a perfect thermal conductor..."
> www.astro.umd.edu/~miller/teaching/astr606/lecture13.ps
Bald, unsupported claims aren't valid references -- even if they are
contained in lecture notes.
> "sudden arrest of bubbling below the ¸-point ('thermal
> superconductor effect',
> see, for example, Lynton, 1964)."
> [http://www.ct.infn.it/MarchHD/hd_en.pdf]
When are you going to learn to give proper references? Citations include
page numbers or section numbers. (In this case, section 4.2).
The full sentence of your deliberately distorted excerpt is the following:
"The He II phase was named 'superfluid' to describe its peculiar behaviour
in transport and excitation experiments, such as non-Newtonian flow
('fountain effect', discovered by Allen and Misener, 1938), propagation of
heat waves ('second sound', first observed by Peshkov, 1944) and sudden
arrest of bubbling below the lambda-point ('thermal superconductor effect',
see, for example, Lynton, 1964)."
This doesn't support your claim that heat transfer is infinite -- finite
propagation of heat waves. And no claim whatsoever that arrest of bubbling
equates to infinite (or perfect) heat transfer.
> Plus the two references I cited back in December.
The two references you cited back in December did not agree with these two.
They mentioned measuring finite thermal transfer rates.
> ................
> > > Barry is using the argument by definition
> > > that he decries so much. First he asks for what I mean by perfect
> > > conductor of heat,
> >
> > A blatantly false claim.
> >
> > We began with a claim by Thomas, that all superfluids were always
> > isothermal. This was justified by the following logic chain: 1) all
> > superfluids are also superconductors of electricity. 2) All
> > superconductors of electricity are also superconductors of heat.
> > 3) All superconductors of heat are always isothermal.
>
> This is a total misunderstanding by Barry of analogies offered
> and of
Thomas's admitted
> confusion between thermal and electrical superconducivity.
Thomas proferred these arguments as a pure "mathematical" proof of his
position. They were "downgraded" to analogies only when Thomas began to
realize his errors (around 12/20).
> My initial claim (second post) was that perfect thermal conductivity
> or thermal superdonductivity of superfluids is due to advection
> currents.
But you've never supported this toss-off claim, or used it to demonstrate
your fundamental claim (that all superfluids are perfectly isothermal to any
degree and scale). You've always relied entirely upon mathematical
variations on the words "super" and/or "perfect" and/or "infinite."
> > We managed to dispose of claims 1) and 2). Thomas was gentleman
> > enough to admit (on 12/20) that his " ... argument that an electrical
> > superconductor should also be a thermal superconductor by analogy
> > to metals where the heat is largely transported by the charge carriers
> > is wrong."
>
> True. But not relevant to the main point.
It *was* relevant to Thomas' initial chain of logic. This little side issue
results from Thomas' false claim that *I* brought in the term "perfect
conductor of heat."
> > Thomas then relied solely upon the following quote from:
> > http://www.tau.ac.il/~lab3/LOWTEMP/lowtemp.html
>
> Thank you for saving me the trouble of digging out this URL again.
>
> > "SUPERFLUIDITY occurs in liquid helium (LHe) below the lambda point,
> > a temperature, where the viscosity becomes zero and the heat
> > conductivity infinite."
>
> > In my reply of 12/21, I noted three websites identifying the apparent
> > measurement of finite heat transfer in superfluids. Thomas
> > immediately snipped these references, without response or
> > acknowledgement.
>
> You place great store in the significance of snippage. I snipped them
> because I thought they were not relevant.
ROTFLMAO! You snipped them (without acknowledgement) because three
experimental citations showed finite heat transfer. When both you and your
source claimed that heat transfer was infinite.
> Finite heat transfer is to be expected
> in a themal superconductor
{snip attempt to bring in the false analogy to electrical superconductors}
Now Thomas (temporarily) abandons his "infinite" term, and his "perfect"
term, and retreats back to his "super" term.
How is this claim supported by the citation, immediately above, that claims
"heat conductivity (is) infinite?" And how does a "thermal superconductor"
compare to a "perfect thermal conductor" in your reference at (A) above?
> > However, I had also noted the following:
>
> > greywolf42:
> > "The only support given on the first website for the statement above
> > is the very next sentence: 'In that case no local overheating is
> > possible which can be seen in the absence of bubbles.' As noted
> > earlier, this is a very slender thread of resoning: 'No bubbles are
> > seen, therefore the heat transfer is infinite.'"
>
> And again you make the same error of reasoning. You jump from evidence
> of perfect thermal conductivity to "heat transfer is infinite". The
> logic of this jump is just not sound.
LOL! *YOUR* original citation (immediately above) claimed "heat
conductivity (is) infinite." I was kind enough to translate this to "heat
transfer is infinite." (which is more liberal). It is only the more recent
attempted citation on your part -- at (A), above -- that uses the term
"perfect thermal conductor".
I once again remind Thomas of his original position:
================
> Here it is on Dec 7 http://tinyurl.com/43qxt
> "Since the fluid has zero viscosity there is
> no resistance to any convective flow caused by thermal differences
> hence thermal differences must be zero, therefore the conductivity
> is infinite."
================
Ever since that effort, Thomas has been dancing around, trying to avoid
admitting that he must require infinite thermal conductivity. By December
12th, Thomas had begun hedging: "If it is superfluid then it must be
perfectly conductive."
Later, Thomas *defined* his new term (perfection instead of infinite) as a
body that was isothermal.
> > {Instead of addressing the weakness of the claim, Thomas changed
> > directions.}
>
> > Thomas:
> > "You still make the same logic error, thinking that perfect thermal
> > conductivity implies infinite heat transfer."
>
> > {Note where Thomas attempts to change the term from the website
> > ("infinite heat conductivity")
>
> If Barry had written "infinite heat conducity" and not
> "heat transfer is infinite" there would have been no argument.
> The two are very different.
LOL! Heat transfer is the sum of heat conduction, heat convection and heat
radiation. If heat conductivity is infinite, then heat transfer will be
infinite.
> > to his own "perfect thermal conductivity."
>
> That is a better way to express it I think.
Sure, because the term "perfect conductivity" is undefined. So it can mean
whatever you want. ;)
> I had hoped it would reduce Barry's confusion.
LOL! Barry never was confused.
> > So, I gave
> > Thomas the ability to use whichever of the two terms he desired:}
>
> Understanding would have been nice.
I understood perfectly. That was the problem. So Thomas brought in a
*third* term for the same concept, in order to try to muddy the water.
> > greywolf42:
> > "That would depend, then, on what you mean by 'perfect thermal
> > conductivity.' Choose whatever term you like, but please provide a
> > physical and/or mathematical basis for the term, so we don't go off
> > on another tangent."
>
> > > and then he uses his own definition to show that
> > > my definition is impossible. Very neat sophist trick.
>
> > Mirror, mirror. I don't have a definition of perfect thermal
> > conductivity.
{snip another attempt to retreat into analogy with electrical
superconductors}
> > PTC is your own, personal and unique term.
>
> But see above.
You have now, at (A), brought in another link that uses this term. But it
is from unreferencable lecture notes.
> > Your reference website used the
> > phrase "heat transfer is infinite."
>
> No. No. It used the phrase "heat conductivity [is] infinite"
> Why does Barry keep making this mistake. Is it
> deliberate?
LOL! In this case, the specific quote *was* my mistake (as I didn't
cut-and-paste). However, perfect heat conductivity is even more limiting
than perfect heat transfer -- so I was giving you a break.
> > If you don't believe that perfect
> > thermal conductivity also includes infintite heat transfer, then you
> > have no support from your claimed supporting website.
>
> Bizarre. There is no reference in that site to "inifinite heat
> transfer". I tried to be careful to exclude this from my definition.
If one has infinite heat conductivity (as your link claims), then you cannot
avoid infinite heat transfer. Because heat transfer is a sum of heat
conduction, heat convection, and heat radiation.
> > > Barry's definition is "perfect heat conductor" is one that is
> > > perfect in all respects to the conduction of heat.
>
> > I don't have a definition of perfect heat conductor. PHC is your
> > own, personal and unique term.
>
> Then where does Barry get "infinite heat transfer" from?
>From fundamental definitions of heat transfer. HT = convection + conduction
+ radiation. Infinite heat conduction => infinite heat transfer.
> > > It can conduct _any_
> > > amount of heat etc. He has distorted my definition which
> > > only says that it conduct _some_ amount of heat etc. The amount
> > > may in fact be quite small.
>
> > And yet if it conducts only an arbitrarily small quantity of heat per
> > second (per meter), then the Lincoln penny still meets the definition.
>
> There was the small matter of zero measured temperature drop.
That was contained in the definition that T_source = T_sink. By definition,
there is no temperature drop.
> > For arbitrarily small is logically the same as zero.
>
> And I did not use the phrase "arbitrarily small quanitity of heat"
> in my defnition.
LOL! Here we go again......
> Maybe I'd better quote it:
> "To give a physical definition, a perfect heat conductor is one
> which when some finite amount of heat energy flows through it
> from a source to a sink, exhibits a temperature drop from the
> source to the sink that is experimentally indistinguishable from
> zero."
> Barry seems to be confusing the word "finite" with
> "arbitrary".
The words are logically identical, in your definition. Or do you claim that
zero is an infinite number?
> > > > What will the temperature of the
> > > > perfect conductor of heat be? [i.e. (T1+T2)/2 ?] How does the
> > > > perfect conductor of heat function?
>
> > > The first question is addressed in the part I am going to snip down
> > > to.
>
> > Nope, you didn't. You simply are avoiding the question.
>
> Barry is misunderstanding.
LOL! Then point to where you addressed the temperature of the perfect
conductor of heat, in terms of T1 and T2.
> > > The second is no-friction, no-viscosity advection currents.
>
> > Is there a physical upper limit on the rate of heat transfer per unit
> > length?
>
> Shouldn't that be per unit area?
In whatever units you choose.
> > This is a yes or no question.
Thomas won't commit himself to yes-or-no.
> If no, the rate is infinite.
>
> Something of order of magnitude the speed of sound
> times the specific heat.
Does this mean you answer "yes?"
> > If
> > yes, then there are conditions where even perfect thermal conductors
> > (whatever they are) are not isothermal.
>
> Does you theory meet these condtions? Is the heat flow that high?
Yes or no, Thomas. Yes or no.
> [I'll snip the discussion of transients for brevity]
LOL! They aren't "transient" conditions, Thomas! Heat transfer is based on
these conditions. I'll replace the summary exchange.
======================
Thomas:
"It's beyond me to model what happens at intermediate times, but as I say
these are transient and I think that no infinities or singularities arise."
greywolf:
"95% of thermodynamics is based on what happens in the "intermediate"
times -- times when the heat has started to flow, steadied down, but not
drained all temperatures to commonality."
======================
> > > .................
>
> > > Then I found this incredible statment:
>
> > > > A Lincoln penny meets your definition for a perfect conductor of
> > > > heat. When you hook it up to a "source" and a "sink" that are at the
> > > > same temperature.
>
> > > Then no heat flows.
>
> > That's my point. In your "definition" of a perfect heat conductor,
> > you require:
>
> > 1) that both the "source" and the "sink" be at the same temperature
> > ("T_source=T_sink to within experimental error as I said").
> > 2) that the resulting heat profile be isothermal.
>
> > I give you Tsource = Tsink on either side of the penny. And the
> > penny is isothermal. Voila! A penny is a perfect thermal
> > conductor.
>
> It is not conducting heat.
How do you know whether your "perfect heat conductor" is conducting heat?
By what observable?
> It fails the definition.
Suppose *I* claim that it is? How do you tell?
> > > Barry just does not understand what a
> > > super(physical-characteristic) implies.
>
> > You already have shown that you didn't understand the properties of
> > electrical superconductors and superconductors of heat -- until I
> > corrected you.
>
> Actually I discovered my own error. Nothing you wrote led me to it.
Sure. It didn't matter that I'd explained it to you half a dozen times
before you found it in your "own" reference. ;)
> > Which is why you abandoned the term "superconductor", when you chose
> > perfect conductor. Otherwise, you'd have had to live with more
> > standard definitions.
>
> I'd use "thermal superconductor" still if there was not so much
> confusion.
LOL! You created the confusion by your creation of the term "perfect"
conductor of heat. You had no other reason than the desire to create
confusion.
> > All you have left is a pathetic analogies based on the prefix
> > "super."
>
> What do you call the used of terms like "pathetic"?
Accuracy. ;)
> > > I snip the rest of Barry's incredible (willful?) misunderstandings.
>
> > LOL! Thomas claims that he has magical materials that make net heat
> > flow between two bodies at the same temperature. He just can't
> > quantify it.
>
> Barry again forgets the distinction between starting the heat flow -
> transient - and maintaining the heat flow - steady state.
Transient does not mean any time perfect isothermality has not yet been
reached.
--
greywolf42
ubi dubium ibi libertas
{remove planet for return e-mail}
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