ET Thermal Conductivity

[craigcocca@gmail.com]

Question:

Is it possible that the change in thermal conductivity between the
alloy used to build the Lightweight ET and the Super Lightweight ET is
the cause of the increased cryopumping that has led to foam loss on the
recent tanks? My understanding is that the new aluminum-lithium alloy
has a much lower thermal conducticity than the old material. I was
thinking that this would result in more thermal energy from ascent
heating being trapped at the foam level, vs before when some of that
energy was transmitted into the tank via the aluminum alloy skin.
Likewise, the decreased TC causes the liquid fuel in the tank to not be
able to keep the trapped liquid gases within the foam as cool as before
during ascent, thus resulting in increased cryopumping and resultant
foam liberation.

NASA hasn't really been able to understand the mechanism for foam
liberation despite three years of intensive work on the matter, so I
figured maybe it was time to get some amateur brain power wokring on
the issue.


-Craig

[Bob Haller]

wrote:
> Question:
>
> Is it possible that the change in thermal conductivity between the
> alloy used to build the Lightweight ET and the Super Lightweight ET is
> the cause of the increased cryopumping that has led to foam loss on the
> recent tanks? My understanding is that the new aluminum-lithium alloy
> has a much lower thermal conducticity than the old material. I was
> thinking that this would result in more thermal energy from ascent
> heating being trapped at the foam level, vs before when some of that
> energy was transmitted into the tank via the aluminum alloy skin.
> Likewise, the decreased TC causes the liquid fuel in the tank to not be
> able to keep the trapped liquid gases within the foam as cool as before
> during ascent, thus resulting in increased cryopumping and resultant
> foam liberation.
>
> NASA hasn't really been able to understand the mechanism for foam
> liberation despite three years of intensive work on the matter, so I
> figured maybe it was time to get some amateur brain power wokring on
> the issue.
>
>
> -Craig

Its a good theory since the loss got worse with the lighter tank.
Perhaps the lighter tank also flexes more?

[Rick Nelson]

Smart once and then dead lined.

Do you think DOW chemical has some involvement on "foam research" there,
buddy?

The NASA engineers have all been switchgrassed to the Mars Mission.


This USA is so foolish and ****ed up.

Thanks,

Rick

[craigcocca@gmail.com]

> The NASA engineers have all been switchgrassed to the Mars Mission.
> This USA is so foolish and ****ed up.


Can we *please* keep this an on-topic engineering discussion?

Thanks,
Craig

[Jorge R. Frank]

wrote in news:1151082016.385112.8260
@u72g2000cwu.googlegroups.com:

> Question:
>
> Is it possible that the change in thermal conductivity between the
> alloy used to build the Lightweight ET and the Super Lightweight ET is
> the cause of the increased cryopumping that has led to foam loss on the
> recent tanks? My understanding is that the new aluminum-lithium alloy
> has a much lower thermal conducticity than the old material.

The old alloy (Al 2219-T87) has a thermal conductivity of 121 W/m-K. The
new alloy (Al-Li 2195), as close as I can tell[1], has a thermal
conductivity of 102 W/m-K. That's lower but I don't know if I'd call it
"much lower".

[1] - actually listed as 0.243 cal/cm-s-C; I hope I got the conversion
right. Who says the metric system doesn't have unit conversion issues?
--
JRF

Reply-to address spam-proofed - to reply by E-mail,
check "Organization" (I am not assimilated) and
think one step ahead of IBM.

[craigcocca@gmail.com]

Jorge R. Frank wrote:

> The old alloy (Al 2219-T87) has a thermal conductivity of 121 W/m-K. The
> new alloy (Al-Li 2195), as close as I can tell[1], has a thermal
> conductivity of 102 W/m-K. That's lower but I don't know if I'd call it
> "much lower".


That's actually pretty substantial. Let me see if I've got this right:

LO2 Temp: 89.81K
Ambient Temp Outside Tank: 293.15K
k Old Alloy: 121 W/m-K
k New Alloy: 102 W/m-K

delta Thermal Energy Transfer= (121 W/m-K - 102 W/m-K) *
(293.15K-89.81K) = 3863.46 Watts per square meter

[Dr John Stockton]

JRS: In article >, dated Sat, 24
Jun 2006 17:01:54 remote, seen in news:sci.space.shuttle, Jorge R. Frank
> posted :
>
>[1] - actually listed as 0.243 cal/cm-s-C; I hope I got the conversion
>right. Who says the metric system doesn't have unit conversion issues?

The calorie is not a Systeme Internationale init.

If people use a hybrid or out of date system, they must accept the
consequences.

--
© John Stockton, Surrey, UK. / ©
Web <URL:http://www.merlyn.demon.co.uk/> - FAQish topics, acronyms, & links.
Correct <= 4-line sig. separator as above, a line precisely "-- " (SoRFC1036)
Do not Mail News to me. Before a reply, quote with ">" or "> " (SoRFC1036)

[Jorge R. Frank]

Dr John Stockton > wrote in
:

> JRS: In article >, dated Sat, 24
> Jun 2006 17:01:54 remote, seen in news:sci.space.shuttle, Jorge R. Frank
> > posted :
>>
>>[1] - actually listed as 0.243 cal/cm-s-C; I hope I got the conversion
>>right. Who says the metric system doesn't have unit conversion issues?
>
> The calorie is not a Systeme Internationale init.

Note my choice of words. SI is a subset of metric. The calorie is not SI
but it is metric.

--
JRF

Reply-to address spam-proofed - to reply by E-mail,
check "Organization" (I am not assimilated) and
think one step ahead of IBM.

[hephaestus@phreaker.net]

> The calorie is not a Systeme Internationale init.
>
> If people use a hybrid or out of date system, they must accept the
> consequences.

Let's face it, the most common failure mode in unit conversions is that
some
engineer assumed a particular measurement was in a particular set of
units,
when it was not.

Unit conversions are easy, even if your inputs are in furlongs per
fortnight.
Actually verifying all your assumptions is hard, and SI units solve
only the
easiest problems you might encounter.

[Dr John Stockton]

JRS: In article >, dated Sun, 25
Jun 2006 13:22:08 remote, seen in news:sci.space.shuttle, Jorge R. Frank
> posted :
>Dr John Stockton > wrote in
:
>
>> JRS: In article >, dated Sat, 24
>> Jun 2006 17:01:54 remote, seen in news:sci.space.shuttle, Jorge R. Frank
>> > posted :
>>>
>>>[1] - actually listed as 0.243 cal/cm-s-C; I hope I got the conversion
>>>right. Who says the metric system doesn't have unit conversion issues?
>>
>> The calorie is not a Systeme Internationale init.
>
>Note my choice of words. SI is a subset of metric. The calorie is not SI
>but it is metric.

One can understand a conservative reluctance to abandon the venerable
system of units which the States acquired when a part of the British
Empire. But it seems unreasonable then to use another obsolete system,
when the rest of the world has moved on.

AIUI, Abba Eban (1915-2002) once said, emulating a more pointed remark
attributed to Sir Winston Churchill, "Men and nations behave wisely once
they have exhausted all the other alternatives." It's about time that
the USA recognised that, in this respect and for technical matters, it
is time to move to the final stage.

--
© John Stockton, Surrey, UK. / ©
Web <URL:http://www.merlyn.demon.co.uk/> - FAQish topics, acronyms, & links.
Correct <= 4-line sig. separator as above, a line precisely "-- " (SoRFC1036)
Do not Mail News to me. Before a reply, quote with ">" or "> " (SoRFC1036)

[John Doe]

"Jorge R. Frank" wrote:
> Note my choice of words. SI is a subset of metric. The calorie is not SI
> but it is metric.

But there are 2 calories.

calory = 4.1855 J
Calory = 4,1855 J

http://fr.wikipedia.org/wiki/Calorie

(aka: Calory is 1000 calories or 1 kilo-calory.)

calory is the amount of energy required to raise 1 gr of water at 14.5°C
to 15.5°C at 101,325 kPa atmospheric pressure.

The two definitions of calory depending on capitalisation can lead to
confusion which you don't want if you have a spacecraft that depends on
such calculations.

Going with Joules (adopted by SI in 1978 as standard) removes that
confusion and also more direct conversions from Newtowns, Watts and even
amps/ohms ( 1 J = 1 ampere going thorugh 1 1 ohm resistor for 1
second).


c/Calories may be good for diets because you never need to convert this
to other units. But for NASA, I suspect they do more than diets and read
labels on Corn Flakes boxes, and would need to use lots of math
formulas, at which point, it becomes much simpler to stick to SI units
that are more easily converted from one to another. The fewer
conversions, the fewer the chances of an error.

[Greg D. Moore \(Strider\)]

"Dr John Stockton" > wrote in message
...
>
> AIUI, Abba Eban (1915-2002) once said, emulating a more pointed remark
> attributed to Sir Winston Churchill, "Men and nations behave wisely once
> they have exhausted all the other alternatives." It's about time that
> the USA recognised that, in this respect and for technical matters, it
> is time to move to the final stage.

Yes, because obviously it's held us back from reaching the Moon like the
Brits.

Or being the first to develop the Atomic Bomb.


>
> --
> © John Stockton, Surrey, UK. /
©
> Web <URL:http://www.merlyn.demon.co.uk/> - FAQish topics, acronyms, &
links.
> Correct <= 4-line sig. separator as above, a line precisely "-- "
(SoRFC1036)
> Do not Mail News to me. Before a reply, quote with ">" or "> "
(SoRFC1036)

[Jorge R. Frank]

Dr John Stockton > wrote in
:

> JRS: In article >, dated Sun,
> 25 Jun 2006 13:22:08 remote, seen in news:sci.space.shuttle, Jorge R.
> Frank > posted :
>>Dr John Stockton > wrote in
:
>>
>>> JRS: In article >, dated
>>> Sat, 24 Jun 2006 17:01:54 remote, seen in news:sci.space.shuttle,
>>> Jorge R. Frank > posted :
>>>>
>>>>[1] - actually listed as 0.243 cal/cm-s-C; I hope I got the
>>>>conversion right. Who says the metric system doesn't have unit
>>>>conversion issues?
>>>
>>> The calorie is not a Systeme Internationale init.
>>
>>Note my choice of words. SI is a subset of metric. The calorie is not
>>SI but it is metric.
>
> One can understand a conservative reluctance to abandon the venerable
> system of units which the States acquired when a part of the British
> Empire. But it seems unreasonable then to use another obsolete
> system, when the rest of the world has moved on.

The rest of the world hasn't quite moved on. I didn't get those aluminum
specs from NASA or any other US government source; I googled them from the
web. The 2219 specs I found on an American website, but I couldn't find the
thermal conductivity of 2195 in W/m-K anywhere.


--
JRF

Reply-to address spam-proofed - to reply by E-mail,
check "Organization" (I am not assimilated) and
think one step ahead of IBM.

[Jorge R. Frank]

"Greg D. Moore \(Strider\)" > wrote in
ink.net:

>
> "Dr John Stockton" > wrote in message
> ...
>>
>> AIUI, Abba Eban (1915-2002) once said, emulating a more pointed remark
>> attributed to Sir Winston Churchill, "Men and nations behave wisely once
>> they have exhausted all the other alternatives." It's about time that
>> the USA recognised that, in this respect and for technical matters, it
>> is time to move to the final stage.
>
> Yes, because obviously it's held us back from reaching the Moon like the
> Brits.
>
> Or being the first to develop the Atomic Bomb.

For that matter, the Russians aren't quite SI-pure yet either; they
routinely list rocket thrusts in kgf rather than newtons. Doesn't appear to
have affected the quality of their rocket engines in a negative way.

--
JRF

Reply-to address spam-proofed - to reply by E-mail,
check "Organization" (I am not assimilated) and
think one step ahead of IBM.

[Ian]

"Greg D. Moore (Strider)" > wrote in message
news:jK_ng.12970>

> Yes, because obviously it's held us back from reaching the Moon like the
> Brits.
>
> Or being the first to develop the Atomic Bomb.


And lately ??

It's a bit like the Greeks saying, "yeah, well we invented the triangle". It
only works for a while.

[Richard Kaszeta]

John Doe > writes:

> "Jorge R. Frank" wrote:
> > Note my choice of words. SI is a subset of metric. The calorie is not SI
> > but it is metric.
>
> But there are 2 calories.
>
> calory = 4.1855 J
> Calory = 4,1855 J
^
I think you're missing a decimal point here.

> calory is the amount of energy required to raise 1 gr of water at 14.5°C
> to 15.5°C at 101,325 kPa atmospheric pressure.

Which, if you're heating water or doing other similar thermal work,
the calorie wasn't an unreasonable unit, which is why the unit was
used as a primary energy unit as long as it was (and why food energy
content is labeled in Calories, since that's actually what they
measure, the increase in water temperature from combusting the food).

> Going with Joules (adopted by SI in 1978 as standard) removes that
> confusion and also more direct conversions from Newtowns, Watts and even
> amps/ohms ( 1 J = 1 ampere going thorugh 1 1 ohm resistor for 1
> second).

I know several experienced engineers from an SI background that still
prefer CGS or MKS units to SI, since that's what they learned and can
most easily estimate quantities in (Ergs, Dynes, Stokes, and Poise,
anyone?)

I agree, the J is much more useful. But you'll probably never shake
some of the more bizarre metric-derived units out there (are, hectare,
and paris points, for example) either.

Just be glad we're not dealing with some of units that are truly
ugly. HVAC work has ugly units in both Metric and Imperial, although
the later is truly ugly (Perms[1], anyone?). I've got all sorts of
NASA docs here in the office that use slinches. And heck, every time I
need to look up thermal conductivities, viscosities, or specific
heats for a material I'm working with, I'm much more likely to find
Imperial or metric-but-not-SI (calorie or Stokes/Poise-based, as the case may
be) than SI units.

> c/Calories may be good for diets because you never need to convert this
> to other units. But for NASA, I suspect they do more than diets and read
> labels on Corn Flakes boxes, and would need to use lots of math
> formulas, at which point, it becomes much simpler to stick to SI units
> that are more easily converted from one to another. The fewer
> conversions, the fewer the chances of an error.

Indeed, but as others have mentioned, lack of double-checks and other
safeguards is the real problem. Units are just a contributing factor.

[1] grains[2] of water vapor per square foot per hour per inch of mercury
partial pressure difference.

[2] 1/7000 lb, for those of you that don't deal in firearms...

--
Richard W Kaszeta

http://www.kaszeta.org/rich

[Brian Thorn]

On Tue, 27 Jun 2006 13:28:59 +1000, "Ian" >
wrote:


>> Yes, because obviously it's held us back from reaching the Moon like the
>> Brits.
>>
>> Or being the first to develop the Atomic Bomb.
>
>
>And lately ??

First successful rovers on Mars?
First successful Saturn orbiter?
U.S. widebody airliners mopping the floor with Europe's rival designs
(even the 40-year-old 747 is kicking A380 ass)?

Brian

[Ian]

"Herb Schaltegger" > wrote in
message .com...
> On Tue, 27 Jun 2006 17:43:00 -0500, Brian Thorn wrote
> (in article >):
>
> You forgot the first four outer-system probes (Pioneers 10 and 11 and
> Voyagers 1 and 2), the first successful Mars landing missions (Vikings
> 1 and 2), the first successful flight of a reusable winged spacecraft,
> various combat aircraft which have set the standards for the world
> since the late mid-1960's, the world's fastest air-launched aircraft
> (X-15), the world's fastest ground-launched aircraft (A-12/SR-71) . . .
>
> Yeah, Imperial units are such a failure . . . :-/
>
> --
> Herb


Yes, very nice work without doubt. Well done and all that. But largely
evolutionary, not revolutionary.

I note that Voyager 1 is now 3.1 × 10^13 cubits from earth. Pardon my
anachronism - I should have said 31 terracubits distant.

Seriously though, it is quite astounding that a reasonably innovative
country can be so tied into an imperial system. It's an act of obeisance to
your once oppressor. Cast off the shackles and be free.

After all, you guys had to *fight* to be rid of the English so you may as
well live a litle. The rest of us just had to make them realise we didn't
like them, and they left of their own accord.

(You guys did it with your stock exchange, and only very recently. The rest
of the world had been using decimals for ages, and you guys were saying that
Enron was up from 87 and nine sixteenths to 87 and nineteen thirty seconds).

[Derek Lyons]

"Ian" > wrote:

>Seriously though, it is quite astounding that a reasonably innovative
>country can be so tied into an imperial system.

Only to an ignorany bigoted jackass could it be so astounding. Grow
the **** up.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

[Ian]

"Derek Lyons" > wrote in message
...
>
> Only to an ignorany bigoted jackass could it be so astounding. Grow
> the **** up.
>
> D.
> --

Very erudite. Nicely proofed.

[Herb Schaltegger]

On Wed, 28 Jun 2006 23:25:11 -0500, Ian wrote
(in article >):

>
> "Derek Lyons" > wrote in message
> ...
>>
>> Only to an ignorany bigoted jackass could it be so astounding. Grow
>> the **** up.
>>
>> D.
>> --
>
> Very erudite. Nicely proofed.
>
>

And o so true.

--
Herb

"Everything is controlled by a small evil group to which,
unfortunately, no one we know belongs."
~Anonymous

[Robert Bonomi]

In article >,
Ian > wrote:
>
>"Herb Schaltegger" > wrote in
>message .com...
>> On Tue, 27 Jun 2006 17:43:00 -0500, Brian Thorn wrote
>> (in article >):
>>
>> You forgot the first four outer-system probes (Pioneers 10 and 11 and
>> Voyagers 1 and 2), the first successful Mars landing missions (Vikings
>> 1 and 2), the first successful flight of a reusable winged spacecraft,
>> various combat aircraft which have set the standards for the world
>> since the late mid-1960's, the world's fastest air-launched aircraft
>> (X-15), the world's fastest ground-launched aircraft (A-12/SR-71) . . .
>>
>> Yeah, Imperial units are such a failure . . . :-/
>>
>> --
>> Herb
>
>
>Yes, very nice work without doubt. Well done and all that. But largely
>evolutionary, not revolutionary.
>
>I note that Voyager 1 is now 3.1 × 10^13 cubits from earth. Pardon my
>anachronism - I should have said 31 terracubits distant.

Yeahbut. can you really use a _terra_-cubit, to measure off-earth distances?

I guess that maybe "forewarned is forearm-ed applies."

[Dale]

On Wed, 28 Jun 2006 14:02:40 +1000, "Ian" > wrote:

>Herb Schaltegger wrote:

>> You forgot the first four outer-system probes (Pioneers 10 and 11 and
>> Voyagers 1 and 2), the first successful Mars landing missions (Vikings
>> 1 and 2), the first successful flight of a reusable winged spacecraft,
>> various combat aircraft which have set the standards for the world
>> since the late mid-1960's, the world's fastest air-launched aircraft
>> (X-15), the world's fastest ground-launched aircraft (A-12/SR-71) . . .
>>
>> Yeah, Imperial units are such a failure . . . :-/

>Yes, very nice work without doubt. Well done and all that. But largely
>evolutionary, not revolutionary.

And the units of measure used contribute somehow to how comfortable
you are with being condescending in your post? What difference do
they make in engineering terms?

>Seriously though, it is quite astounding that a reasonably innovative
>country can be so tied into an imperial system. It's an act of obeisance to
>your once oppressor. Cast off the shackles and be free.

>After all, you guys had to *fight* to be rid of the English so you may as
>well live a litle. The rest of us just had to make them realise we didn't
>like them, and they left of their own accord.

Umm, doesn't Australia still have a Governor General, with the Queen as
head of state?

>(You guys did it with your stock exchange, and only very recently. The rest
>of the world had been using decimals for ages, and you guys were saying that
>Enron was up from 87 and nine sixteenths to 87 and nineteen thirty seconds).

The U.S. has had a decimal currency since the 18th century. Just what is
your point? That Australia has idiots too? Congratulations :)

Dale

[Fred J. McCall]

"Ian" > wrote:

:"Greg D. Moore (Strider)" > wrote in message
:news:jK_ng.12970>
:
:> Yes, because obviously it's held us back from reaching the Moon like the
:> Brits.
:>
:> Or being the first to develop the Atomic Bomb.
:
:And lately ??

Check the Nobel Prize winners.

:It's a bit like the Greeks saying, "yeah, well we invented the triangle". It
:only works for a while.

And what have you done lately?

--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson

[Ian[_1_]]

"Dale" > wrote in message
...
> On Wed, 28 Jun 2006 14:02:40 +1000, "Ian" > wrote:
> >(You guys did it with your stock exchange, and only very recently. The
rest
> >of the world had been using decimals for ages, and you guys were saying
that
> >Enron was up from 87 and nine sixteenths to 87 and nineteen thirty
seconds).
>
> The U.S. has had a decimal currency since the 18th century. Just what is
> your point? That Australia has idiots too? Congratulations :)
>
> Dale

Nope - I'm talking about the stock market, which in the US operated in
*fractions* of a dollar until just a handful of years ago. Decimalisation of
the financial systems was a fairly major undertaking, similar to switching
to a four digit year for y2k.

But I won't call you an idiot. Just impecuniously uninformed about
something.

[Dale[_1_]]

On Thu, 13 Jul 2006 14:18:57 +1000, "Ian" > wrote:

>
>"Dale" > wrote in message
...
>> On Wed, 28 Jun 2006 14:02:40 +1000, "Ian" > wrote:

>Nope - I'm talking about the stock market, which in the US operated in
>*fractions* of a dollar until just a handful of years ago. Decimalisation of
>the financial systems was a fairly major undertaking, similar to switching
>to a four digit year for y2k.

But what is this supposed to prove? The UK didn't switch to a decimal
currency until about 1970. The US has had one almost 200 years longer.
Who cares what the Dow chooses to use? The stock markets are private
organizations, not governmental ones.

World shipping still uses nautical miles. So what?

Earlier, you wrote:

>>(You guys did it with your stock exchange, and only very recently. The rest
>>of the world had been using decimals for ages, and you guys were saying
>>that Enron was up from 87 and nine sixteenths to 87 and nineteen thirty
>>seconds).

There were never any "thirty seconds" (sic), nor any thirty secondths, for that
matter. The base unit was the sixteenth. Perhaps you are impecuniously
uninformed :)

Dale