| Abstract [eng] |
The object of research in this work was a single-chamber solid oxide fuel cell with different working gas composition and construction: a) 2 cathodes and 1 anode were placed in parallel alternately, b) 5 cathodes and 4 anodes were placed as chess. The relevance of this study is to perform modeling with an element that has more than one anode and cathode on one side of the electrolyte. The results obtained by changing the gas composition for variant a) show that the maximum diffusion rate is obtained when the gas mixture consists of gases H2O:O2:CH4 in the proportions 1:1:10, obtaining the highest value 6.4 10-3 mol/(a.u.3 s). In another experiment, the cathode area was increased, which showed that as the area increases, so does the maximum rate of oxygen ion diffusion, which ranged from 1.6 to 3.7 mol/(a.u.3 s) when the area of one cathode varies from 2 10-7 to 5 10-7 a.u.. However, when equilibrium is reached, a slight decrease in the equilibrium diffusion rate is seen as the cathode area changes. The results obtained by changing the area of the anode showed that as the area increases, the maximum rate of oxygen ion diffusion increases, which varies from 1.6 to 7.4 mol/(a.u.3 s) when the area varies from 2 10-7 to 10-6 a.u., at the same time the equilibrium diffusion rate increases, the value of which increases from 2.87 10-3 to 14.4 10-3 mol/(a.u.3 s). It was also shown that in structure a) the region of minimum concentration shrinks closer to the anode, and over time the minimum concentration increases from 0.1674 10-3 to 0.3981 mol/(a.u.3). However, in structure b) the distribution of ions in the electrolyte remains almost unchanged until a state close to equilibrium is reached, after which this area shrinks close to the anodes, its value varies from 6,41 10-4 iki 0,31539 mol/(a.u.3). Also, the areas at the central cathode have the lowest concentration compared to the areas at the remaining cathodes. In the last test, the distance between the electrodes in variants a) and b) was changed. The results showed that as the distance between the electrodes decreased, the maximum rate of oxygen ion diffusion increased. When equilibrium is reached, it can be seen that as the distance between the electrodes decreases, so does the equilibrium diffusion rate. Comparing the equilibrium diffusion rates of structures a) and b) for an anode of the same size, it was found that the structure does not affect the diffusion rate. It has also been observed that the maximum diffusion rate is visible at the cathodes and this rate decreases with distance from the electrodes. However, over time, this area gains the lowest speed. The diffusion rate decreases over time and no significant difference is seen between the diffusion rates of the layers as they move away from the electrodes. |
