[recepky]

Hi fellow CFD users,

I want to model a cylindirical membrane(plenty of membranes) in a cross flow condition, and when I use permemability and C2 coefficients like 2e-16 for face permeability and 3e+12 for C2, problem diverges. I have to use this coefficients because membranes that I want to model, has kind of 0.0001m/s velocity at 100000Pa values. I am sure these coefficients are the reason behind the divergence.

How can I solve this divergence problem ?

Thanks

[oj.bulmer]

As you guessed it, are you sure about these coefficients? How did you arrive at these values?

OJ

[recepky]

hi oj

I arrive this values by plotting xy curve from my experimental data velocity and pressure drop, from the xy polynomial trendline excel generated the y=Ax2+Bx equation that I used to find C2 and alfa permeability coeffitions. I double checked everything that I do in excel. I am sure these coefficients is right. Because these coefficients belongs to a membrane that 0.5micrometer or even lower pore sizes. It has very low permeability compairing to normal filters.

[shubhangini]

Originally Posted by recepky

hi oj

I arrive this values by plotting xy curve from my experimental data velocity and pressure drop, from the xy polynomial trendline excel generated the y=Ax2+Bx equation that I used to find C2 and alfa permeability coeffitions. I double checked everything that I do in excel. I am sure these coefficients is right. Because these coefficients belongs to a membrane that 0.5micrometer or even lower pore sizes. It has very low permeability compairing to normal filters.

i too have the same problem.. it says workbench error.. but when i change face permeability to high value.. the simulation works smoothly.. i.e. my actual value is 1.52e-18 but i am using 1.52e+18 but this is of no use, not getting the correct radial velocity.
It's very disappointing.