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Linearized resistivity with multiple materials
Posted 22 giu 2016, 04:18 GMT-4 Heat Transfer & Phase Change, Materials Version 5.1, Version 5.2 3 Replies
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Hi All,
I am using the Joule Heating study to investigate the heating of a titanium wire on a silicon nitride membrane for thermal conductance simulations. Although I can simulate when there is only Ti wire with added linearized resistivity (defined rho0, alpha, and Tref) when I add Si3N4 layer as it asks for rho0, alpha, and Tref values for Si3N4 domain as well -even though linearized resistivity is not added to Si3N4 material.
I tried writing this, which gave me no syntax error when written
rho0 --> Inf
alpha --> 0
Tref --> 300 [K]
However, it cannot complete the simulation and result in an error:
I would appreciate any help.
Thanks!!
Failed to find a solution.
Segregated Step 1
Singular matrix.
There are 11217 void equations (empty rows in matrix) for the variable comp1.V.
at coordinates: (-5e-006,-2.5e-006,-2.5e-006), (-5e-006,-1.78571e-006,-2.5e-006), (-5e-006,-2.14286e-006,-2.5e-006), (-5e-006,-2.5e-006,-2.14286e-006), (-5e-006,-2.5e-006,-1.78571e-006), ...
and similarly for the degrees of freedom (empty columns in matrix).
In Segregated Step 1:
Returned solution is not converged.
- Feature: Stationary Solver 1 (sol1/s1)
I am using the Joule Heating study to investigate the heating of a titanium wire on a silicon nitride membrane for thermal conductance simulations. Although I can simulate when there is only Ti wire with added linearized resistivity (defined rho0, alpha, and Tref) when I add Si3N4 layer as it asks for rho0, alpha, and Tref values for Si3N4 domain as well -even though linearized resistivity is not added to Si3N4 material.
I tried writing this, which gave me no syntax error when written
rho0 --> Inf
alpha --> 0
Tref --> 300 [K]
However, it cannot complete the simulation and result in an error:
I would appreciate any help.
Thanks!!
Failed to find a solution.
Segregated Step 1
Singular matrix.
There are 11217 void equations (empty rows in matrix) for the variable comp1.V.
at coordinates: (-5e-006,-2.5e-006,-2.5e-006), (-5e-006,-1.78571e-006,-2.5e-006), (-5e-006,-2.14286e-006,-2.5e-006), (-5e-006,-2.5e-006,-2.14286e-006), (-5e-006,-2.5e-006,-1.78571e-006), ...
and similarly for the degrees of freedom (empty columns in matrix).
In Segregated Step 1:
Returned solution is not converged.
- Feature: Stationary Solver 1 (sol1/s1)
3 Replies Last Post 24 giu 2016, 03:31 GMT-4
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Posted:
8 years ago
I had solved the problem by just simply giving rho0 a very large value compared to the Ti resistivity.
However, the fundamental problem still exists: Do I have to define linearized resistivity for all materials if I have more than one material in the simulation?
Any thoughts?
Thanks!
-Ozan
However, the fundamental problem still exists: Do I have to define linearized resistivity for all materials if I have more than one material in the simulation?
Any thoughts?
Thanks!
-Ozan
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Posted:
8 years ago
Hi,
No, you should only need to define it for the materials in the domains where you use a linearized resistivity. If you add Linearized Resistivity to the default Current Conservation node, you probably need to define another Current Conservation node that overrides the default one in the domains where you don't want to describe the electrical conductivity using a linearized resistivity.
Best regards,
Magnus Ringh, COMSOL
No, you should only need to define it for the materials in the domains where you use a linearized resistivity. If you add Linearized Resistivity to the default Current Conservation node, you probably need to define another Current Conservation node that overrides the default one in the domains where you don't want to describe the electrical conductivity using a linearized resistivity.
Best regards,
Magnus Ringh, COMSOL
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Posted:
8 years ago
Dear Magnus,
Thank you for your input! I had overlooked the domain selection window apparently. Thanks for pointing it out so elegantly, problem solved.
-Ozan
Thank you for your input! I had overlooked the domain selection window apparently. Thanks for pointing it out so elegantly, problem solved.
-Ozan