USLABO subroutine

[frpageot]

Hello,

I am still working on the efficiency estimation of a cyclonique filter, and I am trying to adjust calculation results to the experimental ones. I am using the USLABO subroutines for that, and in the CS version I am using (2.0.2), part 6 of the subroutine there is an exemple with a DVLO deposition conditions. A constant is used equals to 3.34d-12 which is multiplied to the particle diameter, an I just would like to have an explanation of this constant. Can someone helps ? Thanks.

[guingo]

Hello Fred,

As you may know, the DLVO conditions for particle deposition in Code_Saturne v2.0.2 are activated with the "idepfa" keyword for Lagrangian boundary conditions. Basically, the proposed (and somewhat crude) implementation of the DLVO theory consists here in, when a particle is detected to "cross" this kind of boundary, comparing the wall-normal contribution of the particle kinetic energy and a possibly present so-called "energy barrier" (depending on ionic strength on the medium, on the Zeta potentials on the particles and wall, etc.) at the wall, which would prevent particle deposition. (DLVO theory is well described in the Israelachvili textbook on intermolecular and surface force, in my point of view)

This kind of condition is especially (and to my knowledge, almost only) useful when the study deals with the effect of pH on particle deposition. As far as I know, the particular value 3.34e-12 that appears in the standard uslabo.f90 in CS v2.x is the "height" of the energy barrier from a particular test-case formerly used to develop this condition, and must be adapted by the user. A warning for the user to adapt this value is thus clearly missing. By the way, a more complete implementation of the DLVO theory is planned to be proposed in CS 3.0

Best regards,
Mathieu

[frpageot]

Thanks for your answer. That's a real coincidence that I was reading your thesis while you made the answer to my question !