Analysis of Two-Phase Flow Patterns of Hydrogen and Distilled Water in a Microchannel with Sudden Expansion

Abstract

One of the challenges in realizing the development of a hydrogen-based economy is hydrogen transportation. Several studies
have been conducted to improve the efficiency of hydrogen transportation, one of which is by using two-phase flow. Identifying
the flow pattern is important because with a certain flow pattern will make it more efficient. The selection of the working fluid
in two-phase flow greatly affects the characteristics of the flow pattern. Aquadest has high purity properties, is clear, odorless,
and has no taste. These characteristics make it the right choice for applications in microfluidic systems, especially
microchannels that have a high surface area to volume ratio. The presence of the sudden expansion phenomenon in the
microchannel is expected to have a significant impact on the flow characteristics, including changes in pressure, velocity, and
flow distribution. The purpose of this study is to analyze the two-phase flow pattern in microchannels with sudden expansion.
The working fluids used in this study are hydrogen gas and distilled water. The superficial velocity is varied to obtain the flow
pattern. The superficial gas velocity (jG) is varied in the range of 0.67-13.33 m/s, while the superficial liquid velocity (jL) is in
the range of 0.1-1 m/s. The characteristics of the flow patterns formed were recorded using a high-speed camera and the
observed flow patterns included bubbly, slug, slug-annular, and churn.