Study of two-phase flow distribution in microchannel heat exchanger header - A numerical simulation

Abstract

In the present paper, the two-phase flow distribution in the microchannel heat exchanger (MCHE) header is numerically studied, and the proper void fraction model, two-phase flow and turbulence models are obtained by comparing simulation results with the experimental results data. Numerical results show that the VOF model and SST k-ω turbulence model have a better performance in predicting two-phase flow distribution of vapor and liquid mass flow rates in each microchannel tubes under different refrigerant inlet qualities. Furthermore, the flow and phase distribution in a really-used longer MCHE header (length >400mm) with 55 microchannel tubes are numerically analyzed. Results indicate that the two-phase refrigerant in the distribution tube sprays from the distribution hole, and an annual liquid film forms on the inner wall of the header because of the frictional forces between wall and refrigerant.

Keywords

• Numerical model
• Two-phase distribution
• Microchannel header
• Void fraction