Theoretical Investigation of Flow Regime for Boiling Water Two-Phase Flow in Horizontal Rectangular Narrow Channels

The flow regime transition criteria for the boiling water two-phase flow in horizontal rectan- gular narrow channels(1×20mm,2×20mm) were theoretically explored. The discernible flow patterns were bubbly, intermittent slug, churn, annular and steam-water separation flow. By using two-fluid model, equa- tions of conservation of momentum were established for the two-phase flow.New flow-regime criteria were obtained and agreed well with the experiment data.