3D computational fluid dynamics-based analysis of water transfer characteristics of hollow fiber membrane for gas-to-gas membrane humidifier

Abstract

Water in a proton exchange membrane fuel cell is the main factor determining its performance and durability. A humidifier provides water vapor to regulate the humidity of the fuel cell and enable proper operation. The water transfer properties of membranes are investigated through experiments, and simulations enable faster prediction and optimization of various operating conditions. In this study, a numerical simulation model using the diffusion coefficient empirical formula was developed to calculate the water vapor transport. User-defined function codes are applied to predict mass transfer using the concentration difference between the wet and dry surfaces of the membrane. The results were analyzed by the water transfer rate, mass fraction, and pressure characteristics of the influence of flow rate, pressure, temperature, humidity, and the number of membranes of 9 or 21. The analysis model predicted the experimental results with high reliability of R-square 0.96. It was confirmed that a high flow rate increased the outlet water transfer flux, and an increase in the tube decreased the water transfer flux.