Investigation on the phase split characteristics of slug and annular flow in a metal foam-filled T-junction

Abstract

The application of metal foam in the flow boiling phase of transformation heat can greatly increase the nuclear nucleation rate, increase the fluid disturbance, and increase the heat exchange area, thereby greatly improving the heat exchange efficiency. However, the metal frame structure can increase the complexity of the channel interior, which may cause serious water shortages in some branches. Aiming at this problem, this paper investigated the characteristics related to the flow moved through a small heat transfer channel filled with metal foam at a T-junction. Experiments focused on the relationships between the phase split and the flow pattern as well as the two-phase superficial velocity and the pores per inch (PPI) effect of the metal foam. A 2.5 × 2.5 mm rectangular channel dividing at a T-junction filled with metal foam was used in the experiment. Air is the gas medium and water is the liquid medium. Results showed that after the channel was filled with metal foam, the liquid taken off was better than when the channel was not filled with metal foam. The liquid taken off from side branch decreased with an increase in PPI. When the PPI number reach 10, the liquid taken off gets the best result. At last, four predictive models of phase split characteristics for the two flow patterns with different PPI were developed, which was verified by experimental results showing high accuracy.