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Open Boundary Condition in Tranposrt of Dilute Species
Posted 23 feb 2012, 16:36 GMT-5 Chemical Reaction Engineering, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.2a 2 Replies
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I am working with a model where I am only simulating a small subset of the complete geometry. This is essentially a circular pipe with perforations. I am not simulating nor incorporating the larger vessel in which the fluid leaks into. My models shows that some fluid may be leaving the pipe in the first few perforations and entering in the second portion of my pipe. Due to this velocity/flow observation, I need to implement different boundary conditions when addding in my transport of diluted species equation. I would like to use the Open Boundary condition on the perforation so that I can define the concentration outside of the tube. This si very important for the second half of my pipe where flow in coming back into the tube.
When I try to implement this Open Boundary condition on my holes in steady state mode, I get: Attempt to evaluate negative power of zero. - Function: ^" .
Does any know how to properly define thuis type of boundary condition.
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I don't know does this has anything to do with open boundary but I had similar problems in my Transport of Dilute Species model. I made variable "C" which is defined by "if(c<0,eps,c)" under Definitions => Variables. Instead of concentration "c" I used variable "C". Now variable "C" is never below zero. Eps is very small number defined is Comsol.
Does this help you?
Best regard
Tero
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