Thesis for degree: Licentiate of Engineering

4 Results
and discussion
This section presents the results from the LB model and the criteria for the kinetic parameters
are checked so that no critical effects occur on the transport processes. Both the LB model
and the validation of the kinetic effects are viewed from a microscale perspective. Also the
results of the macroscale model are provided and divided into two parts; change of internal
reforming reaction rate model and change of amount of methane content and steam-to-fuel
ratio.
4.1 Microscale model by LBM
The LB model stops when the maximum deviations of the mean velocity differ with less than
10 -10 over the last iteration. Reynolds number is calculated based on the velocity and is
relatively low Re typically in the order of 0.1 to 1. The physical geometry of the LB model
and material data for the anode is presented in Table 4.1. In the LB model discrete units are
used for the length and time. The lattice unit lu represents the fundamental measure of length
and time step ts the measure of time.
Table 4.1: Anode geometry and relevant parameters [1].
Anode
Size
Length 40 lu, 200 lu 1
Height 10 lu, 50 lu 1
Porosity (ε) 0.4
Inlet mole fraction
H 2 0.9
H 2 O 0.1
The study is conducted in an order of increasing complex geometries to validate the method
for future modeling of all the physical processes in an SOFC. First of all, a small test is
1 Two different values for this parameter are tested.
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