Response of a proton exchange membrane fuel cell to step changes in mass flow rates

Abstract

Transient regime effects are particularly important in fuel cells designed for vehicles. Three-dimensional modeling of a proton exchange membrane fuel cell with a serpentine channel is presented, and the response of the fuel cell to a step-change in the mass flow rates is analyzed by using the computational fluid dynamics techniques. After a validation study of the mathematical and numerical model, step increases of 20% in mass flow rates are applied to the inlet boundary conditions, and time dependent power and current density responses of the fuel cell are analyzed. Polarization curves are generated for the assessment of the fuel cell performance, and their variations in time are presented. The results show that current and power densities increase with time at low cell voltage values due to concentration losses; however, increases in power and current are negligible at high voltages.

Optimal Heat‐Up Planning of a Solid Oxide Fuel Cell with and without Hot Air Recycling by Considering Energy, Time, and Temperature Gradient

“…To simulate the heat-up process, the equations of conservation of mass, momentum, and energy are solved in their transient form with the assumptions of laminar flow regime, homogeneous porous media, and ideal behavior of all gas species. [10,28,50] Equation (1) shows the conservation of mass, in which ũ is the velocity vector, t represents the time, and ε shows the porosity of porous media. [10,28,50] Also, ρ denotes the gas density which is calculated from the ideal gas law as shown in Equation ( 2), where P, T, and R are pressure, temperature, and gas constant, respectively: [10,50]…”

“…The harmful environmental impact of fossil fuel usage, the depletion of fossil fuel resources, and the ever-increasing global energy demand had led researchers to seek alternative energy resources. [1][2][3] Fuel cells, as a group of clean energy systems, have attracted special attention and been employed in various applications such as transportation, power generation, and space missions. Fuel cells consume hydrogen (fuel) and oxygen, and produce electricity, water, and heat as a result of some electrochemical reactions.…”

Modelling of Fuel Cells and Related Energy Conversion Systems

“…Transient effects are significant for mobile applications, and were the focus of a 3-D CFD study of a PEMFC with a serpentine channel. A step-change in the mass flow rates resulted in current-and power-density increases with time at low cell voltage due to concentration losses, but this was negligible at high voltages [60].…”

Multiscale Modelling of Fuel Cells and Related Energy Conversion Systems

“…Transient effects are significant for mobile applications and were the focus of a 3-D CFD study of a PEMFC with a serpentine channel. A step-change in the mass flow rates ends in current and power densities increase with time at low cell voltage due to concentration losses, but negligible at high voltages [46].…”