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Total flux not zero in steady state solution
Posted Dec 5, 2011, 3:22 a.m. EST Version 4.2 1 Reply
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Hi!
I am simulating a semiconductor quantum well system and have a rather simple flux question. The specifics of the model is not very important, but I am using the transport of dilute species to model the electron populations in different part of the structure.
I have a layered (2D) structure A-B-C. Layers A and C has one electron population and layer B has a separate electron population. I have manually set the flux A<->B and B<->C using the 'flux' node in transport of dilute species. All other boundaries have the 'no flux' condition set.
Comsol manages to find a solution both in equilibrium, and also with voltages applied to A and C, however if I integrate the flux through the boundary AB and BC, they are not equal. I guess this means I have two questions
- Since the flux (I integrate the actual flux expressions, not the flux COMSOL tells me since this is not accurate) into B and out from B are not equal, that means this is not a steady state solution, since the electron population will be changing with time? How is this handled in COMSOL and why does it find this as a steady state solution?
- Is there anyway in comsol to set a constraint, such that the integral of flux along over all boundaries of B should be zero?
Kristian
I am simulating a semiconductor quantum well system and have a rather simple flux question. The specifics of the model is not very important, but I am using the transport of dilute species to model the electron populations in different part of the structure.
I have a layered (2D) structure A-B-C. Layers A and C has one electron population and layer B has a separate electron population. I have manually set the flux A<->B and B<->C using the 'flux' node in transport of dilute species. All other boundaries have the 'no flux' condition set.
Comsol manages to find a solution both in equilibrium, and also with voltages applied to A and C, however if I integrate the flux through the boundary AB and BC, they are not equal. I guess this means I have two questions
- Since the flux (I integrate the actual flux expressions, not the flux COMSOL tells me since this is not accurate) into B and out from B are not equal, that means this is not a steady state solution, since the electron population will be changing with time? How is this handled in COMSOL and why does it find this as a steady state solution?
- Is there anyway in comsol to set a constraint, such that the integral of flux along over all boundaries of B should be zero?
Kristian
1 Reply Last Post Dec 12, 2011, 1:12 a.m. EST
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Posted:
1 decade ago
Hi,
I have quite the same problem. Does none know a solution?
Elmar
I have quite the same problem. Does none know a solution?
Elmar