Experimental Study On The Distribution Characteristics Of Gas-Liquid Two-Phase Flow In Parallel Micro Channels

In order to meet the necessity of green energy-saving and high-tech development, micro-chemical technology has attracted extensive attention from researchers since the 1990 s, due to its various advantages, such as high efficiency, flexibility, rapidity, and highly integration.As a basis for the research and application of micro chemical technology, several efforts have been made to study the gas-liquid two phase flow in micro-channels over recent years. Up till now, a majority of the relevant studies have been mainly focused on a single channel with straight pipe or branch pipe conduits, and few researches of gas-liquid two phase flow in parallel micro-channels have been reported so far. However, a single micro-channel cannot meet our needs in industrial application since many industrial processes such as the integration of the reaction components in micro reactor and tiny electronic equipment cooling, are mostly based on the parallel micro-channels. On the other hand, different from the single micro-channel with a straight pipe or branch pipe conduits, the uneven phase splitting behavior will be more pronounced when a gas-liquid two phase flow passes through a parallel micro-channel, leading to a big discrepancy of gas-liquid two phase ratio between the main pipe and the parallel branches, thus causing extremely negative impact on the equipment operational efficiency. In view of this, an experimental investigation was carried out to study the gas-liquid two phase splitting behavior in the parallel micro-channels with hydraulic diameters of the header and branch channels 0.6 mm and 0.4 mm, respectively.Current experiments were conducted under atmospheric pressure(100kPa) and room temperature(25℃). Micro-channels with parallel branches were made from polymethyl methacrylate(PMMA) rectangular block to make visual observation. As expected, serious phase mal-distribution was observed during the visual experiments. The effect of inlet flow pattern, wettability of micro-channels and number of parallelbranches on the characteristics of gas-liquid two-phase flow distribution through parallel micro-channels were investigated.With abscissa denoting the serial number of corresponding branches counted from the inlet of header and ordinate presenting the gas /liquid phase taken off through the corresponding parallel micro-channels, figures revealing phase splitting characteristics were drawn. By comparison of the data obtained in those figures, some relevant conclusions could be achieved as follows:(1)Gas-liquid two phase distribution characteristics in parallel micro-channels are significantly affected by inlet flow pattern;(2)With the decrease of channel number, much more uneven two-phase distribution phenomena have been observed in our experiments;(3)Microchannel inner wall wettability has extensive influence on two phase distribution characteristics.