Numerical Simulation of Gas-liquid Circulation Flow of RH

Experiment and numerical simulation of RH circulation flow was carried out on water model. Helium gas was injected into water in up-leg and flow rate was estimated at the bottom of down-leg. Volume of fluid (VOF) simulation was also performed by compressibleInterfoam solver of OpenFOAM, open source CFD toolbox. Three pairs of diameter of up/down-leg, 100 mm/100 mm, 140 mm/70 mm and 170 mm/30 turn were estimated and the circulation flow rate was compared to Ono et al.'s estimated formula. The flow rate in 100 mm/100 mm and 140 mm/70 mm were almost consistent with that of Ono et al.'s formula, but it was half in 170 mm/30 mm. Simulated flow rate of all pairs were almost consistent with measurement. The visualization of experiment and simulation showed that down flow through up-leg occurred in case of 170 mm/30 mm, and it was thought to cause lower flow rate through down-leg than Ono et al.'s relation. lt was important to use sufficiently small mesh for up-leg to get flow rate correctly becase of the necessity of resoluting the shape of bubble. Finally the simulation with scaled up mesh and molten steel properties was carried out. The volume of injected gas became larger according to rising in the up-leg because of hydrostatic pressure distribution and the behavior of gas-liquid interface in vessel was simulated qualitatively.