Advanced Energy Technologies
Tuhid Pashaee Golmarz; Sajadollah Rezazadeh; Maryam Yaldagard; Narmin Bagherzadeh
Abstract
In the present work, a Proton-Exchange Membrane Fuel Cell (PEMFC) as a three-dimensional and single phase was studied. Computational fluid dynamics and finite volume technique were employed to discretize and solve a single set of flow fields and electricity governing equations. The obtained numerical ...
Read More
In the present work, a Proton-Exchange Membrane Fuel Cell (PEMFC) as a three-dimensional and single phase was studied. Computational fluid dynamics and finite volume technique were employed to discretize and solve a single set of flow fields and electricity governing equations. The obtained numerical results were validated with valid data in the literature and good agreement was observed between them. The main purpose of this paper is to investigate the effect of deformation of the geometric structure of a conventional cubic fuel cell into a cylindrical one. For this purpose, some important parameters indicating the operation of the fuel cell such as oxygen distribution, water, hydrogen, proton conductivity of the membrane, electric current density, and temperature distribution for two voltage differences between the anode and cathode and the proposed models were studied in detail. Numerical results showed that in the difference of voltages studied, the proposed new model had better performance than the conventional model and had a higher current density, in which at V = 0.4 [V], about a 10.35 % increase in the amount of electric current density was observed and the average increment in generated power was about 8 %, which could be a considerable value in a stack of cells. Finally, the discussion of critical parameters for both models was presented in more detail. The core idea of the results is that the Oxygen and Hydrogen utilization, water creation, and heat generation are greater in the new model.
Advanced Energy Technologies
Haleh Sadeghi; Iraj Mirzaei; Shahram Khalilaria; Sajad Rezazadeh; Mojtaba Rasouli Gareveran
Abstract
Among the renewable energy systems, fuel cells are of special significance about which more investigation is required. The principal goal of the present study is considering the effect of the geometry change on the fuel cell's performance. In this paper, a three-dimensional model of proton exchange membrane ...
Read More
Among the renewable energy systems, fuel cells are of special significance about which more investigation is required. The principal goal of the present study is considering the effect of the geometry change on the fuel cell's performance. In this paper, a three-dimensional model of proton exchange membrane fuel cell has been numerically simulated with conventional cubic geometry. Afterwards, two brand-new cylindrical models have been proposed to compare and select the best model. The governing equations include mass, momentum, energy, species and electrical potential, which are discretized and solved using the method of computational fluid dynamics. The results obtained from numerical analyses were validated with those from experimental data, which showed acceptable agreement. For the above-mentioned models, changes in the species mass fraction, temperature, electric current density, and over-potential were analyzed in more detail. The results reveal that, in all three models, by decreasing the amount of cell voltage differences between the anode and the cathode, higher current density is produced, which leads to high input species consumption and, consequently, more water and heat generation. On the other hand, the four-channel cylindrical model is more efficient than the other two models and has shower pressure drop due to its shorter pathway. The results illustrated that, at V=0.6 )V(, the amount of the output current density in the four-channel model increased by approximately 18.4 %, compared to that in the other two models. Further, in this model, the material used in bipolar plates is less than that in the other models.
Advanced Energy Technologies
Tuhid Pashaee Golmarz; Sajad Rezazadeh; Narmin Bagherzadeh
Abstract
In this paper, a three-dimensional, single-phase proton-exchange membrane fuel cell (PEMFC) is studied numerically. Finite volume method was used for solving the governing equations and, consequently, the numerical results were validated by comparing them with experimental data, which showed good agreement. ...
Read More
In this paper, a three-dimensional, single-phase proton-exchange membrane fuel cell (PEMFC) is studied numerically. Finite volume method was used for solving the governing equations and, consequently, the numerical results were validated by comparing them with experimental data, which showed good agreement. The main objective of this work is to investigate the effect of a novel gas channel shape– by applying sinusoidal gas channel- on the cell performance and mass transport phenomena. Some parameters such as oxygen consumption, water production, protonic conductivity, and temperature distribution for two cell voltages were studied, and the results were compared with respect to conventional and new models. The results indicated that the new novel model showed better performance than the conventional model, especially at low cell voltages, causing an increase in oxygen consumption and water production. Therefore, based on a number of investigated relations, a higher rate of current density was obtained, thus enhancing the fuel cell performance. This is because the incoming species path to the gas channels in the new model becomes longer. Therefore, the diffusion of the species toward the electrochemical reaction area increased.
Sajad Alah Rezazadeh; Iraj Mirzaie; Nader Pourmahmoud; Nima Ahmadi
Abstract
A full three-dimensional, single phase computational fluid dynamics model of a proton exchange membrane fuel cell (PEMFC) with both the gas distribution flow channels and the Membrane Electrode Assembly (MEA) has been developed. A single set of conservation equations which are valid for the flow channels, ...
Read More
A full three-dimensional, single phase computational fluid dynamics model of a proton exchange membrane fuel cell (PEMFC) with both the gas distribution flow channels and the Membrane Electrode Assembly (MEA) has been developed. A single set of conservation equations which are valid for the flow channels, gas-diffusion electrodes, catalyst layers, and the membrane region are developed and numerically solved using a finite volume based computational fluid dynamics technique. In this research some parameters such as oxygen consumption, water production, temperature distribution, ohmic losses, anode water activity, cathode over potential and the fuel cell performance for straight single cell were investigated in more details. The numerical simulations reveal that these important operating parameters are highly dependent to each other and the fuel cell efficiency is affected by the kind of species distribution. So for especial uses in desirable voltages, for preventing from the unwilling losses, these numerical results can be useful. Finally the numerical results of proposed CFD model have been compared with the published experimental data that represent good agreement.