Compute the Conductivity
ConductoDict
The ConductoDict module simulates thermal and electrical conduction experiments and post-process the simulation results to predict the thermal and electrical conductivity. In addition, temperature and potential distribution as well as the distribution of heat flux, current density, and the electric field are computed.
A conduction experiment in ConductoDict requires as input:
- 3D representation of a structure or material
- Conductivity for each constituent material in the structure
- Experimental process parameters, such as temperature or potential at the inlet and outlet domain boundary
Examples of Applications
Many industrial applications (e.g. thermal insulation, carbon nano-tubes) and research projects successfully use the methods in ConductoDict, e.g.:
- Heat transfer properties of:
- medium density fiberboard (MDF) samples
- cast iron microstructures
- gas diffusion layer in fuel cells
- Electrical conductivity of Ag/SnO
- Electrical conductivity and formation factor of sandstones etc.
Influence of Wall Thickness on Thermal Conductivity
- Scope: Determination of thermal conductivity with
ConductoDict to avoid intensive experimental work - Input: Physical properties of base material (polypropylene)
Cell size: 90 µm, wall thickness: 3 µm, 4 µm, 5 µm, 6 µm - Result: Wall thickness ↑ ➤ Thermal conductivity ↑
Influence of Cell Size on Thermal
Conductivity
- Scope: Determination of thermal conductivity with
ConductoDict to avoid intensive experimental work - Input: Physical properties of base material
(polypropylene), Fixed wall thickness: 5 µm - Result:: Cell size ↑ ➤ Thermal conductivity ↓
Compute Formation Factor
Compute the effective electrical conductivity and obtain the Formation Resistivity Factor (FF)
(a) Electrical Potential
From inlet to outlet, Gildehauser*
(b) Electrical field
High values (red) in pore throats
*Berg et al., 2016, https://doi.org/10.1016/j.advwatres.2016.01.010
Electrical Properties of GDLs: Experimental and Numerical Validation
The study examines electrical conductivity of
Toray TGP-H-060 GDL, comparing experiments and
simulations under compression with good agreement.
(a) Segmented CT-scan of TGP-H-060 at three different
compression levels. Colors indicate current density strength.
* Becker, J., et al., “Determination of Material Properties of Gas Diffusion
Layers: Experiments and Simulations Using Phase Contrast Tomographic
Microscopy”, Journal of The Electrochemical Society, 2009, 156(10).
The ConductoDict module can be used to perform thermal and electrical conduction simulations using the LIR or EJ solver:
Compute Thermal Conductivity
The thermal conductivity tensor is computed. This is done by solving the stationary heat equation per direction of interest. The thermal conductivity of the constituent materials is taken into account which can be isotropic, transverse-isotropic, or orthotropic. In addition, contact resistance between different materials or different object of the same material can be prescribed. As output, ConductoDict assigns a single, effective heat conduction tensor to the whole data set. The temperature and heat flux distribution is also computed and can be visualized in the graphical user interface.
Compute Electrical Conductivity
The electrical conductivity tensor is computed. This is done by solving the governing equation for electric potential which combines the continuity equation for current and Ohm's law. The electrical conductivity of the constituent materials is taken into account which can also be isotropic, transverse-isotropic, or orthotropic. Similar to thermal conduction, contact resistance between different materials or different object of the same material can be taken into account to model imperfect contact. As output, the effective electrical conductivity tensor for the whole data set is computed. In addition, the potential, current density, and electric field distribution is computed and can be visualized in the graphical user interface. The formation resistivity factor is also computed based on the resisvitiy of a fluid in the pore space. This is a critical propertiy in petrophysics and geophysics.
Following Modules are often used in combination with ConductoDict:
| Image Processing and Image Analysis | ImportGeo-Vol | ||
| Material Analysis | GrainFind | FiberFind | PoroDict + MatDict |
| Modeling & Design | Application-relevant modules for creating and modeling 3D microstructure models in GeoDict | ||
| Simulation & Prediction | SatuDict | ||
| Interfaces | |||
Suitable modules depend on the concrete application.