Investigation on the flow regime stability of natural-circulating two-phase system Parti: modeling of the flow regime

摘要

The cryogenic flow regime in a downcomer of reservoir may change from single phase natural convection to natural-circulating two phase flow because of heat leakage to the downcomer. This results a periodic sequence of vapour-bubble buoyancy, agglomeration and condensation, which cause the transition of two phase flow regimes, including bubble flow and slug flow. Basing on the drift-flux model of two phase flow and the dynamic boundary condition concept, dynamic models of flow regime transition in this downcomer have been established. These models may conduce to simulation of flow regime transition, and investigation of stability of flow regime.