Study of two-phase flow characteristics in the interrupted microchannels

Abstract

The key factor restricting the use of microchannels in the cooling of micro-electronic equipment is the non-uniformity of the flow and temperature distribution. In this paper, the structure of the interrupted microchannel is improved by numerical simulation, coupling the Volume of Fluid (VOF) method with the Level-Set (LS) method to quantify the two-phase characteristics of the new microchannel using gas-liquid flow ratios, relative standard deviations, and pressure drop fluctuations. The simulation results proved that the effect of inertia force is largely offset by the widening design of the two side branches, and the flow resistance in the downstream branches is balanced. The effect of microchannel boiling heat transfer was enhanced by gas-liquid phase separation, and the gas flow relative standard deviation value of the interrupted microchannel was 83.1% lower than that of the traditional microchannel at the limit of high void fraction. The liquid-phase flow ratio increases with the inlet void fraction increasing, while the gas-phase flow ratio decreases. The relative standard deviation of the gas-to-liquid flow ratios were 0.215 and 0.134 for an inlet gas volume fraction of 0.2 and the mass flow rate of 80 kg/h, respectively, at which point the flow distribution was supported by the relative standard deviation. In addition, the fluctuation of pressure drop in different pipeline sections is opposite to the changing trend of void fraction, and the fluctuation frequency is the same. At the same time, the amplitude of pressure difference fluctuation under different flow patterns is defined, which provides a new idea for future flow pattern judgment.