An Experimental Investigation Into the Effect of Surfactants on Air-Water Two-Phase Flow in Minichannels

The complex interfacial phenomena involved in two-phase gas-liquid flow have defied mathematical simplification and modeling. However, the systems are used in heat exchangers, condensers, chemical processing plants, nuclear reactor systems, and fuel cells. The present work considers a 1 mm square minichannel and adiabatic flows corresponding to practical PEM fuel cell conditions. Pressure drop data is collected over mass fluxes of 4.0 to 33.6 kg/m²s, which correspond to superficial gas and liquid velocities of 3.19–10 m/s and 0.001–0.02 m/s respectively. The experiments are repeated with water of reduced surface tension, caused by the addition of surfactant, in order to quantify the surface tension effects, as it is recognized that surface tension is an important parameter for two-phase flow in minichannels. The accuracy of various two-phase pressure drop models is evaluated. A new model for laminar-laminar flow is developed.