One-dimensional numerical calculation for unsteady gas-liquid flow in micro channels with air gaps

A numerical calculation model for gas-liquid unsteady two-phase flow in a micro channel was established and validated. The model focuses on flow in a channel including air gaps. It also reduces calculation cost by minimizing the number of control-volume elements compared with conventional numerical methods for gasliquid two-phase flow. Gas-liquid two-phase flow in channels with diameters of 1 to 2 mm is important in liquid transportation in chemical processing and analysis. As for designing flow channels in chemical processing and analysis, simple numerical models are desirable to evaluate many possible patterns quickly. The model uses moving boundaries that correspond to gas-liquid interfaces, but it represents boundaries between different channels with fixed boundaries. By setting several different configurations of air gaps, the numerical model was validated in regard to position and volume of air gaps in the channel. As an application of the numerical model to the design of flow channels in chemical processing and analysis, the necessary movement conditions of a syringe pump to achieve quick liquid transportation were investigated. By applying the numerical model, the necessary conditions to minimize flow rate oscillation were determined. In simulation-based design of microchannel, the numerical model in this research is an effective tool to determine design parameters quickly.