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Protonic ceramic fuel cell (PCFC) has attracted more and more research attention due to its special working features, compared with both the traditional oxygen ionic solid oxide fuel cell (O²⁻-SOFC) and protonic exchange membrane fuel cell (PEMFC). The 3D CFD numerical method is generally considered to be an effective path to explore the proper air...
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... Tortuosity factor Introduction SOFC, as a green energy conversion device, has aroused researchers' widespread interest on account of its several advantages such as high efficiency, low emission, high power density, and compactness [1][2][3][4]. In order to fulfill the voltage and power requirements of practical applications, many single cells should be connected by interconnector to form a SOFC stack [5][6][7]. Hence, interconnector is a significant component of stack, which offers fuel and oxygen for the electrochemical reaction via the channel of interconnector. ...
For the anode-supported solid oxide fuel cells (SOFC), the relatively thin cathode limits the oxygen transfer in-plane. In order to enhance the oxygen transfer in-plane, the interconnector with sinusoidal wavy channel is proposed for SOFC, termed the sinusoidal wavy interconnector (SWI). The effect of SWI is evaluated by numerical method. The oxygen transfer in-plane is promoted, especially at trough position, where the rib width is minimum. For SWI, the maximum oxygen concentration achieves 0.21 mol/m³ on the center line of the cathode/electrolyte interface, which is almost zero for the conventional interconnector. Finally, the effect of amplitude and cycle number on SOFC performance is investigated in detail. The result shows that the average oxygen concentration enhances with the increase of amplitude (A) and cycle number (Pe). When A is 0.4 mm, the average oxygen concentration is 1.51 mol/m³, an increase of 14.39 % from the conventional interconnector (A = 0 mm) of 1.32 mol/m³. In addition, for A = 0.25 mm, the average oxygen on the cathode/electrolyte interface is improved by 18% when Pe increases from 0 to 16. On the other hand, if the amplitude or cycle number is too large, the hindrance caused by the undulating side surface of SWI results in remarkable power consumption. Hence, when cycle number is 16, the effective power achieves the maximum at A = 0.35 mm, which increases by 18.3% compared to the conventional interconnector (A = 0).
... Based on that, mathematical modeling is a unique tool that has been created, which reduces the cost and dependency on repeated experimentation techniques. These needs are satisfied using CFD techniques to develop PCFCs [24,[38][39][40][41]. CFD tools help to study the transport processes and performance of PCFCs very quickly [35]. ...
... Dai and their team also designed 3D models of PCFC stacks (25 cells) with two types of air-flow routes, such as U-type and Z-type, to investigate the best possible air-flow layout of the PCFC stack, as illustrated in Figure 6a [39]. This three-dimensional model of the air-flow path includes (a) one inlet manifold, (b) thirty-six rib channels to disperse the airflow throughout the surface of the cell unit, and (c) a porous cathode current collector and function layers to improve the oxidant and product diffusions. ...
... If both entry and exit of the inlet and outlet manifolds are situated on the same sides, it can be defined as a U-type path. In the Z-type air-flow pattern, the entrance of the inlet manifold and the exit of the outlet manifold are situated on opposite sides, as shown in Figure 6b [39]. They also constructed SOFC structures with U-and Z-type flow paths to compare and analyze the distribution characteristics with the PCFC stacks. ...
Protonic ceramic fuel cells (PCFCs) are one of the promising and emerging technologies for future energy generation. PCFCs are operated at intermediate temperatures (450-750 °C) and exhibit many advantages over traditional high-temperature oxygen-ion conducting solid oxide fuel cells (O-SOFCs) because they are simplified, have a longer life, and have faster startup times. A clear understanding/analysis of their specific working parameters/processes is required to enhance the performance of PCFCs further. Many physical processes, such as heat transfer, species transport, fluid flow, and electrochemical reactions, are involved in the operation of the PCFCs. These parameters are linked with each other along with internal velocity, temperature, and electric field. In real life, a complex non-linear relationship between these process parameters and their respective output cannot be validated only using an experimental setup. Hence, the computational fluid dynamics (CFD) method is an easier and more effective mathematical-based approach, which can easily change various geometric/process parameters of PCFCs and analyze their influence on its efficiency. This short review details the recent studies related to the application of CFD modeling in the PCFC system done by researchers to improve the electrochemical characteristics of the PCFC system. One of the crucial observations from this review is that the application of CFD modeling in PCFC design optimization is still much less than the traditional O-SOFC.
The conductivity of the electrolyte of a proton conductor solid oxide fuel cell is not only related to temperature, but also related to the humidity and oxygen partial pressure of the cathode and anode. The gas partial pressure and temperature of the cell have significant inhomogeneity in three-dimensional space, so it is extremely important to develop a multi-field coupled three-dimensional model to explore the electrochemical performance of the cell. In this study, a model is constructed that takes into account macroscopic heat and mass transfer, microscopic defect transport, and the reaction kinetics of defects. The results show that for thin cathodes, the ribs significantly affect the oxygen partial pressure and the concentration of defects on the cathode side. On both sides of the electrolyte membrane, the concentration of hydroxide ions increases with increasing gas humidity. The hydroxide ion concentration increases along the flow direction, but the concentration of O-site small polarons increases on the anode side and decreases on the cathode side. The conductivity of hydroxide ions is more sensitive to the humidity of the anode side, while the conductivity of O-site small polarons is more sensitive to the humidity of the cathode side. Increasing the humidity of the cathode side results in a significant decrease in the conductivity of the O-site small polarons. The contribution of the conductivity of oxygen vacancies to the total conductivity is negligible. The total conductivity on the cathode side is greater than that on the anode side; it is dominated by hydroxide ions on the anode side, and co-dominated by hydroxide ions and O-site small polarons on the cathode side. Increasing temperature significantly increases both partial and total conductivity. When hydrogen depletion occurs, the partial conductivities and the total conductivity exhibit a sharp increase downstream of the cell.
With the in-depth research of solid oxide fuel cell (SOFC), the advantages of the protonic ceramic fuel cell (PCFC) have been paid more and more attentions. In this paper, three-dimensional calculated fluid dynamics model was built to investigate the fluidity within a typical PCFC stack. The result shown that for a typical PCFC stack, the air mass flow rate fed to the piled layers would keep decreasing with the increasing cell number index, while the inlet and outlet manifolds had similar cross section areas. Extending the length of the membrane electrode assemblies (MEA) would slightly improve the air flow distribution uniformity. The air flow and species distributions among the rib channels would be determined by the sites of the entrances and exits of the manifolds. and the solid rib configuration over porous cathodes. The vapor mole fraction distribution over the dense electrolyte surface had apparently oppositely with the rib channel configuration, because two mole vapors were generated while one mole oxygen is consumed. Different from the O-SOFC stack, the vapor removing capacity would be an important factor for evaluating the quality of the cathode side flow path structure © 2022 The Authors. Published by ESG (www.electrochemsci.org). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/4.0/)
As a result of its advantages in the mid-temperature range, the proton ceramic fuel cell (PCFC) has gotten much attention compared to other fuel cells. In PCFC, whereby the vapor is generated at the cathode side, a flow field with high efficiency in water removal should be in its repertoire. A new inter-parallel flow field was designed and compared to the traditional flow fields: the serpentine, the parallel, and interdigitated flow fields to check its capacity to be a potential flow field for PCFC. The one-cell stack 3D model with the inter-parallel flow field was simulated to analyze the working details within the stack. The design harnessed the advantages of its three unique flow paths in solving the balance problem of pressure drop and effective oxygen transport and water removal. Results show that the design is a potential flow field for the cathode side of the PCFC.
