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Ken
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 Posted: Fri Jul 25, 2003 8:12 pm Post subject: gas flow through capillary/thin tube |
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I>ve got a series of packed-bed columns in which the pressure drop
across each is a moderate function of the technique used in packing
it.
I>d like to make the pressure drop more independent of the nature of
the packing material. I am considering putting small-diameter
capillaries into the line above each column, making the gas throughput
rate largely dependent on the flow resistance of the capillary.
I>m wondering how to best estimate what sort of a capillary will be
necessary for this. At some point, the rules for flow through large
pipes start to break down. At what point does this happen?
I>m also wondering if anyone can suggest tables or equations which
describe the relationship between pressure drop, gas throughput, and
capillary/tube diameter and length. The tubes I>m aware of at this
point go down to an ID of 0.005"
Also, is anybody familiar with companies which produce capillaries
suitable for such purposes?
Thanks,
Ken |
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Ben
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| Posted: Sun Jul 27, 2003 3:51 pm Post subject: Re: gas flow through capillary/thin tube |
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"Ken" <k_yasuda@eudoramail.com> wrote in message
news:f78efa99.0307250712.4dd56aec@posting.google.com...
.....
[quote]I>m also wondering if anyone can suggest tables or equations which
describe the relationship between pressure drop, gas throughput, and
capillary/tube diameter and length. The tubes I>m aware of at this
point go down to an ID of 0.005"
....[/quote]
Try a Google search for Poiseuille; you>ll even find an on-line calculator
(which I haven>t actually tried).
Ben |
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Rouan
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| Posted: Fri Aug 01, 2003 5:25 pm Post subject: Re: gas flow through capillary/thin tube |
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[quote]"Ken" <k_yasuda@eudoramail.com> wrote in message
news:f78efa99.0307250712.4dd56aec@posting.google.com...
....
I>m also wondering if anyone can suggest tables or equations which
describe the relationship between pressure drop, gas throughput, and
capillary/tube diameter and length. The tubes I>m aware of at this
point go down to an ID of 0.005"
...
[/quote]
Agilent Technologies have written a calculator for determining
pressure drops and flow rates through gas chromatography columns down
to 0.01mm ID. You can edit the gas type with physical properites of
your gas medium.
Go to this URL to download:
http://www.chem.agilent.com/cag/servsup/usersoft/main.html#flowcalc205
Thanks, Rouan. |
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Rouan
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| Posted: Fri Aug 01, 2003 5:27 pm Post subject: Re: gas flow through capillary/thin tube |
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k_yasuda@eudoramail.com (Ken) wrote in message news:<f78efa99.0307250712.4dd56aec@posting.google.com>...
[quote]Also, is anybody familiar with companies which produce capillaries
suitable for such purposes?
[/quote]
Look for suppliers of HPLC (high performance liquid chromatography) consumables.
PEEK, steel and other materials are available.
Thanks, Rouan. |
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Max
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| Posted: Wed Aug 13, 2003 9:09 pm Post subject: Re: gas flow through capillary/thin tube |
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Look up for Lucas-Washburn Equation, which correlate capillary
pressure to fluid flow in the capilllary. In the simple model the
density is constant, I am not sure if this is the case for you.
Max |
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