ThermoDict computes the effective thermeal conductivity of porous and composite materials. The user enters the thermal conductivity of the constituent materials and direction(s) of conduction. For each direction of interest, ThermoDict sets up the system of equations of purely diffusive heat transport as described in [1] and solves this system. Then, by appropriate integration, ThermoDict provides the effective thermal conductivity.

ThermoDict does not consider advection or radiation.

ThermoDict can be used to compute effective electric conductivity as well. One ignores the units and specifies the electric conductivity of the constituent materials and ThermoDict provides the effective electrical conductivity, albeit with the wrong units.

The algorithm [1] in ThermoDict has been used for a number of applications, in industrial settings (e.g. thermal insulation) and for academic purposes. Publications include heat transfer properties of medium density fiberboard (MDF) samples [2], of cast iron microstructures [5], of the gas diffusion layer in fuel cells [3, 4, 6, 7, 9] and electrical conductivity of Ag/SnO₂ [8].

[1] A. Wiegmann and A. Zemitis, EJ-HEAT: A Fast Explicit Jump Harmonic Averaging Solver for the Effective Heat Conductivity of Composite Materials, Report of the Fraunhofer ITWM, Nr. 94, 2006.

[2] H. Thoemen, T. Walther und A. Wiegmann, 3D Simulation of Macroscopic heat and mass transfer properties from the microstructure of wood fibre networks, Composites Science and Technology, No. 3-4, Vol. 68, 2007, pp 608-616.

[3] V.P. Schulz, P.P. Mukherjee, J. Becker, A. Wiegmann and C.Y. Wang, Modeling of Two-phase Behavior in the Gas Diffusion Medium of Polymer Electrolyte Fuel Cells via Full Morphology Approach, Journal of the Electrochemical Society, Issue 4, Vol. 154, 2007, pp B419-B426.

[4] J. Becker, V. Schulz and A. Wiegmann,Numerical Determination of Two-Phase Material Parameters of a Gas Diffusion Layer Using Tomography Images, Journal of Fuel Cell Science and Technology, No. 2, Vol. 5, 2008, pp 21006-21014.

[5] A. Velichko, A. Wiegmann, F. Mücklich, Estimation of the effective conductivities of complex cast iron microstructures using FIB-tomographic analysis, Acta Materialia, Vol. 57, 2009, pp 5023-5035.

[6] J. Becker, R. Flückiger, M. Reum, F. Büchi, F. Marone and M. Stampanoni, Determination of Material Properties of Gas Diffusion Layers: Experiments and Simulations Using Phase Contrast Tomographic Microscopy, Journal of The Electrochemical Society, Vol. 156, No 10,pp B1175-B1181 (2009).

[7] N. Zamel, X. Li, J. Shen, J. Becker and A. Wiegmann, Modeling of Two-phase Behavior in the Gas Diffusion Medium of Polymer Electrolyte Fuel Cells via Full Morphology Approach, Chemical Engineering Science, 2010.

[8] N. Jeanvoinea, A. Velichko, C. Selzner, and F. Mücklich, Nanotomography of electrical contacts - new insights by high resolution 3D analysis of local material degradation, Eur. Phys. J. Appl. Phys. 49, p. 22907 (2010).

[9] D. Veyret and G. Tsotridis, Numerical determination of the effective thermal conductivity of fibrous materials. Application to proton exchange membrane fuel cell gas diffusion layers, Journal of Power Sources Vol. 195, No. 5, pp 1302-1307 (2010).

[10] A. Pfrang, D. Veyret F. Sieker and G. Tsotridis, X-ray computed tomography of gas diffusion layers of PEM fuel cells: Calculation of thermal conductivity, International Journal of Hydrogen Enegery, 35, No.8, pp 3751-3757 (2010).