Simulation of two regime sodium flows in a parallel plate channel during buoyancy-driven flow

Due to the remaining decay heat, the reactor core has yet to be cooled after shutdown. As the reactor power is low, the core can be sufficiently cooled by natural convection. The coolant flow is driven by buoyancy, as the heated fluid decreases its density. During buoyancy-driven flow, a reverse flow may take place when a heat sink exists close to the heat source, such as in a wall (edge) or corner subchannels. For simplicity in applying boundary condition, the reverse flow is simulated by two parallel plates, one as a heat source having positive heat flux and the other as heat sink with negative heat flux.

► We simulate two regime flows in edge sub channel of LMFR during natural circulation. ► The fRe is higher than 96 for negative Re number. ► The fRe is lower than 96 for positive Re number. ► The average of hot and cold walls Nu number is 4.1.