Study of interface gas-liquid flow characteristics in a rectangular microchannel for wavy-annular flow

The aim of this work is an experimental study of a gas-liquid flow in a rectangular slit microchannel with a cross-section of 200 × 2045 μm. Ethanol/water (95/5) mixture and nitrogen are used as working liquid and gas, accordingly. The external T-mixer is used for obtaining of wavy-annular flow pattern. The experimental data on interfacial waves and their characteristics in the meniscus area on the short side of the microchannel are obtained using high-speed visualization for a wide range of gas and liquid superficial velocities. Images are processed using the Python libraries to define the average liquid layer thickness and maximum amplitude of waves. An increase of gas superficial velocity causes decreasing in the average liquid layer thickness and maximal amplitude of the liquid layer thickness. The waves on the liquid layer surface (maximal amplitude) can be three times larger than the average liquid layer thickness for presented liquid and gas velocities. With increasing gas superficial velocities more liquid displace from the meniscus area to the liquid film on the wide side of the microchannel.

The effect of the liquid layer thickness on the dissolution of immersed surface droplets

We investigate, both numerically and theoretically, the effect of the thickness of the surrounding liquid layer on the lifetime of dissolving surface droplets.

A Phase Spectrum Method for the Measurement of Liquid-Layer Thickness

Ultrasonic technology has been widely used to measure the thickness of lubricant film. The time delay between multiple reflections reflects the thickness of the liquid layer. As the thickness of liquid layer decreases, the measurement becomes more difficult owing to the overlapping of waveforms. Unlike the mainstream methods focusing on the characteristics of amplitude, a phase spectrum method is proposed in this paper to determine the thickness, which is much easier to operate and doesn’t need any extra noise reduction. It provides another point of view to solve the problem of film thickness measurement. This algorithm has been verified to test the liquid layer thickness ranging of 10–200 μm in a self-made experimental platform. Experimental results show that the thickness can be obtained accurately and the error is within the allowable range.

The effect of the liquid layer thickness on the evaporation intensity

An experimental study of the influence of thermo-capillary forces and shear stresses with the side of the gas flow to the evaporation flow rate has been made. The experiments were carried out at various thicknesses of the liquid layer and constant gas velocity. The influence of the thickness of the liquid layer on the evaporation flow rate (the intensity of evaporation) has been analyzed. It is shown that the thermocapillary forces have a direct effect on the evaporation flow rate of the liquid layer.