# Surface reaction boundary condition

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 March 11, 2011, 06:08 Surface reaction boundary condition #1 New Member   Raphael Tornay Join Date: Mar 2011 Location: Switzerland Posts: 4 Rep Power: 15 Dear all I am trying to simulate a situation where molecules transported by a liquid flowing in a channel can adsorb on the channel walls. Because the molecules do not affect the liquid transport I can start by simulating this (steady state) flow. This works reasonnably well. In a second stage I would like to add the transport of the molecule and its adsorption on the walls. The idea is to simulate the scalar transport with the adsorption/reaction as boundary condition (this is done e.g. by Squires, Messinger and Manalis,Nature Biotechnology 26, 417 - 426,2008 ). The scalar transport is described by a convection-diffusion equation and I think it's exactly what scalartransportfoam does. The reaction is a standard first order reaction: d b(t)/dt = kon*c*(bmax-b)-koff*b, where b is the surface concentration of the adsorbed molecule (and is what I ultimately want to calculate), c is the bulk concentration of the free molecule and kon/koff are the forward and backward rate constants. This means that I need to define a variable on boundaries only and simulate it. I have been browsing the forum for quite some time (e.g. on equations on boundaries) but I could not, with my very limited knowledge of openfoam, get a feeling of whether this is indeed possible and how much effort it would be to implement it. I would appreciate your feeling on this and maybe some pointer to documentation as a starting point. Cheers r

June 16, 2013, 23:29
#2
Member

Ovie Doro
Join Date: Jul 2009
Posts: 99
Rep Power: 16
Quote:
 Originally Posted by Raph Dear all I am trying to simulate a situation where molecules transported by a liquid flowing in a channel can adsorb on the channel walls. Because the molecules do not affect the liquid transport I can start by simulating this (steady state) flow. This works reasonnably well. In a second stage I would like to add the transport of the molecule and its adsorption on the walls. The idea is to simulate the scalar transport with the adsorption/reaction as boundary condition (this is done e.g. by Squires, Messinger and Manalis,Nature Biotechnology 26, 417 - 426,2008 ). The scalar transport is described by a convection-diffusion equation and I think it's exactly what scalartransportfoam does. The reaction is a standard first order reaction: d b(t)/dt = kon*c*(bmax-b)-koff*b, where b is the surface concentration of the adsorbed molecule (and is what I ultimately want to calculate), c is the bulk concentration of the free molecule and kon/koff are the forward and backward rate constants. This means that I need to define a variable on boundaries only and simulate it. I have been browsing the forum for quite some time (e.g. on equations on boundaries) but I could not, with my very limited knowledge of openfoam, get a feeling of whether this is indeed possible and how much effort it would be to implement it. I would appreciate your feeling on this and maybe some pointer to documentation as a starting point. Cheers r

Hi,

Have you made any progress on this solver? I am working on a similar project but with much less complexities with respect to the wall adsorption process. Can you share some of your insights?

Thanks.

 June 19, 2013, 03:38 #3 New Member   Raphael Tornay Join Date: Mar 2011 Location: Switzerland Posts: 4 Rep Power: 15 Hi I unfortunately cannot help you there: I did not pursue this project forward (pretty much left it at this stage). Cheers r

June 19, 2013, 12:24
#4
Member

Ovie Doro
Join Date: Jul 2009
Posts: 99
Rep Power: 16
Quote:
 Originally Posted by Raph Hi I unfortunately cannot help you there: I did not pursue this project forward (pretty much left it at this stage). Cheers r
OK.

Thanks.