Alan, Mark, etal.,
For spheres packed tightly the vacant volume fraction is about 30%. If the density of Li-Al-H is 1, the density of the packed material does not change, however the volume of the actual crystalline solid substance is still 1. From what has been reported I would guess the LiAlH is about 2 sent from Windows Mail From: AlanG Sent: Wednesday, February 11, 2015 8:47 AM To: [email protected] 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 >
