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Chemistry, Geometry, Concentration units (kg/m^3) 1D (4.0a)
Posted Oct 31, 2010, 3:35 p.m. EDT 1 Reply
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Dears (COMSOL 4.0a) users,
I am trying to re-write a model from COMSOL 3.5 to 4.0a,
My reactor is 10 meters long (x-axis), so I need to draw a line. Apparently there are two ways to draw the line: using "points" or using "interval" . If I use the "point" option, there are only two points: one at 0 m (representing INLET) and the other at10 m (representing OUTLET). If I use the "interval" option and for example I choose [0,1,10], the 10 meters long representing my reactor height is divided in 10 points. My question is therefore the following: In the interval option, considering that I have "10 segments" that are drawn, does that mean that my conditions at the inlet are applied for EACH of those ten lines, or only to the first one? (Please see example below).
point 1 .__________.point 2 ( point option)
This means IN _____________________OUT
point 1._._._._._._._._._.point 10 (interval option)
Does this means IN_OUT IN_OUT IN_OUT (10 times) or IN _._._._._._._._._._OUT?
The other question: I want to put concentration units as Kg/m^3, but I only see the options mol/m^3 . Is there a way to put kg/m^3? Considering that the substance I am using isn't pure (it is a complex mixture), I am unable to convert kg to mol (not knowing the molecular weight of this complex substance). Therefore, I am looking for the possibility to use kg/m^3. How can I do this?
Thank you for help.
Regards,
Raul Rodriguez
1 Reply Last Post Nov 1, 2010, 2:32 a.m. EDT
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Posted:
1 decade ago
Hi
normally you should use a "line", I believe and you should get 1 line, but probably when you mesh it you will have 10 elements. And you should only put your conditions on the end points, as the default "continuity will assure the regular flow between the "internal" element points cutting up your line.
Concerning the units, often you have several possible, if not transfor it with one of the built-in physical constants try a help search on physical constants, you will find N_A_const (DO NOT FORGET TO ADD the suffix "_const" after the name shown, it's written but easy to overlook ;)
test it out as a "Parameter" because there COMSOL shows you the result too and you can easily check it it is correct
--
Good luck
Ivar
normally you should use a "line", I believe and you should get 1 line, but probably when you mesh it you will have 10 elements. And you should only put your conditions on the end points, as the default "continuity will assure the regular flow between the "internal" element points cutting up your line.
Concerning the units, often you have several possible, if not transfor it with one of the built-in physical constants try a help search on physical constants, you will find N_A_const (DO NOT FORGET TO ADD the suffix "_const" after the name shown, it's written but easy to overlook ;)
test it out as a "Parameter" because there COMSOL shows you the result too and you can easily check it it is correct
--
Good luck
Ivar