Prediction and parametric analysis of bubble humidifier performance in a polymer electrolyte membrane fuel cell test system by response surface methodology

Abstract

ABSTRACT Bubble humidifiers are widely used in fuel cell test systems to humidify the gas entering the fuel cell to improve the output performance. In this study, response surface methodology was used for experimental design and testing to investigate the humidification performance of an air bubble humidifier for a 100-kW fuel cell test system. Four operating parameters, the air flow rate, operating temperature, gas pressure, and water level, were considered in this study over ranges of 2000–7000 SLPM, 40–80°C, 1.5–2.5 bar, and 15–45 cm, respectively. The sensitivity analysis of the operating parameters and the combined effects of various operating conditions on the humidification performance were examined. The results showed that at different water temperatures, the relative humidity of the outlet air increased by about 2%–6% as the inlet gas pressure was increased, while the relative humidity decreased by about 3%–5% as the inlet air flow rate was increased. At a water temperature of 60°C and an air pressure of 2 bar, increasing the water level in the low flow rate experiments did not produce any advantages, but increasing the water level at high flow rates had a greater impact on the performance of the humidifier. This work can provide theoretical guidance for the humidity control of bubble humidifiers.