Mark, the powders were already inside the glove box when the scale (also
inside the box) failed, so volume measurements were the only data I had
available. As a result, precise mass measurement was not possible, nor
was determination of exact densities by measurement. The relative
density of the powders was taken from the bulk densities as given in the
respective Wikipedia entries. Unknowns include the packing ratio of each
of the powders. They are both finely divided but not nano scale, so
assuming a similar packing seems reasonable in the absence of other data.
The volumes were calculated from dimensions of the actual components
used, measured with a digital caliper. The space between the filler rod
and the ID of the tube is significant and was included in my
calculation. The possible vacant volume within the powder mass was not
included, nor was the possible absorption of H2 into the nickel, which
we think was minimal given the time scale of the experiment.
Regarding the calculation itself, the mass of the fuel was determined
accurately by weighing the loaded cell after sealing and removal from
the glove box. This was divided by the volume mix ratio, then by the
estimated relative density ratio of the two powders to get the mass of
the LiAlH4 in the cell. The amount of H was then found simply by the
ratio of standard atomic weights. As you correctly pointed out earlier,
the equivalent molar amount must be based on the H2 molecules in the
gas, and that was the final figure used to calculate the pressure.
If I missed something important in my analysis, I'd be happy to know,
and make further corrections.
AlanG
On 2/10/2015 11:30 PM, Mark Jurich wrote:
New MFMP Charge Analysis regarding the Explosion Run:
http://bit.ly/1z61hEB (5 hours ago)
This is a shocker to me. Here are the changes to the last values
(first analysis):
Free Volume for Gas: 1.09 ml --> 1.06 ml (not a large change) (Recall
that Parkhomov estimates 2 ml in his experiment(s))
Weight Amount of Li(AlH4): 134 mg --> 19.7 mg (!!!!!!!)
(Recall that Parkhomov/Translation states 100 mg)
With these new values, the calculated pressure become approx. 1500
psi, which agrees with my calculation. But this new weight amount of
Li(AlH4) is totally strange to me. The analysis goes on to state that
this pressure is in line with Parkhomov's estimates, but as far as I
understand, using far less Li(AlH4) than Parkhomov. The only value I
have ever seen stated by Parkhomov is 100 mg, or a factor of 5 times
more, by weight.
Am I missing something here? This is a tremendous change that I'm
having a hard time comprehending. I'm looking into the MFMP
Calculation further, right now.
Thanks,
Mark Jurich
-----Original Message----- From: Mark Jurich
Sent: Sunday, February 08, 2015 2:56 AM
To: [email protected]
Subject: [Vo]:Re: Dog Bone Project
I believe there maybe an error in this pressure estimate and that the
calculated pressure will be exactly half of 19,861 psi (i.e., 9,930.5
psi).
Although 0.0141 moles of Hydrogen are released, 0.00706 moles of Hydrogen
Gas (H2) are released. I don't believe that free H atoms/ions
contribute to
the gas pressure in the free volume of the cell, and that the actual gas
there is H2 Gas.
Please see the following post for the details:
https://www.mail-archive.com/[email protected]/msg101557.html
Mark Jurich
-----Original Message----- From: Craig Haynie
Sent: Sunday, February 08, 2015 1:44 AM
To: [email protected]
Subject: Re: [Vo]:Re: Dog Bone Project
Pressure inside the dog bone is calculated to have been near 19,861 psi
at the time of failure.
https://docs.google.com/document/d/1BWYbi6tBHcjZ4PyQ0BaWn-G1NkdQdkirb-_Qx2HypKs/edit
Craig
