Comparison of Numerical and Experimental Studies for Flow-Field Optimization Based on Under-Rib Convection in Polymer Electrolyte Membrane Fuel Cells

Abstract

Abstract:The flow-field design based on under-rib convection plays an important role in enhancing the performance of polymer electrolyte membrane fuel cells (PEMFCs) because it ensures the uniform distribution of the reacting gas and the facilitation of water. This research focused on developing suitable configurations of the anode and cathode bipolar plates to enhance the fuel cell performance based on under-rib convection. The work here evaluated the effects of flow-field designs, including a serpentine flow field with sub channel and by pass and a conventional serpentine flow-field on single-cell performance. Both the experiment and computer simulation indicated that the serpentine flow field with sub channel and by pass (SFFSB) configuration enables more effective utilization of the electrocatalysts since it improves reactant transformation rate from the channel to the catalyst layer, thereby dramatically improving the fuel cell performance. The simulation and experimental results indicated that the power densities are increased by up to 16.74% and 18.21%, respectively, when applying suitable flow-field configurations to the anode and cathode bipolar plates. The findings in this are the foundation for enhancing efficient PEMFCs based on flow field design.

Numerical Investigations of the Combined Effects of Flow Rate and Methanol Concentration on DMFC Performance

“…With a constant input methanol concentration, e.g., 1.0 mol/L as shown in Figure 6a, the overall color of current density distribution becomes lighter and brighter with the increase of input flow rate. It is in good agreement with the experimental evidence that the more the methanol (fuel) is pumped into a certain energy conversion system, the more the energy can be generated [9,10,18]. With a constant input flow rate, the low current density region (in dark blue) decreases gradually with the increase of input methanol concentrations, which is apparent for a low input flow rate of 1.0 mol/L (see the left column of Figure 6).…”

“…The source term S m and S mon in Section 2.2. The flow fields can be determined by solving Equations (3) and (10). The obtained flow rate − → v is then applied in Equation (12) to determine the convection and diffusion of species.…”

“…A typical DMFC is primarily composed of a Polymer Electrolyte Membrane (PEM), the catalyzed electrodes at anode/cathode sides and the end plates, as shown in Figure 1. The understanding of energy conversion process is necessary for optimal operation and design, but it is a task full of challenges as it normally involves lots of operating parameters, such as the feed solution properties [9] and the flow characteristics [10]. As the underlying mechanism of such a multi-parameter dependent system is usually hard to be experimentally determined, the comprehensive modelings of DMFC systems are essential in optimization design and operational management.…”

Comparison of Liquid Water Dynamics in Bent Gas Channels of a Polymer Electrolyte Membrane Fuel Cell with Different Channel Cross Sections in a Channel Flooding Situation

“…The polymer electrolyte membrane (PEM) fuel cell has received considerable attention due to its many advantages, including zero/low emissions, high power density, low operating temperature, and a broad range of applications [1][2][3][4][5][6][7][8]. The PEM fuel cell generates electricity and by-product water through the electrochemical reaction of hydrogen and oxygen.…”

“…In automotive vehicle applications of PEM fuel cells where the demand for high current density is frequent, water flooding is a critical issue. Therefore, the water removal in the GC is one of the most important issues in PEM fuel cell studies, especially in a GC flooding condition [1][2][3].…”