CFD Simulation of Operational Parameters Effects on Mixing Quality of Two-phase Gas-Liquid Flow in Agitated Vessel

In this contribution, behavior of gas phase distribution in a two phase gas-liquid stirred vessel with Rushton turbine was studied by computational fluid dynamic (CFD) technique at different operational conditions. Multiphase flow regime in the in the two phase gas-liquid vessel was modeled by Eulerian-Eulerian multiphase flow approach. Due to complex hydrodynamics and turbulent flow in the agitated vessel, RNG k-ε was used to simulate turbulence flow behavior. With study of operational conditions by means of Aeration and impeller Reynolds dimensionless numbers, distribution of gas phase volume fraction was studied in the vessel. The results showed minimum hold up of the gas phase exists between vessel bottom up to impeller and maximum gas phase hold up is formed in the impeller zone. Also, it was observed due to the formation of larger vortex areas with increase in impeller Reynolds number the mixing quality in the vessel improves. Furthermore, it was shown that increase in Aeration and impeller Reynolds numbers enhances gas phase holdup in the vessel. Study of impeller Power number showed that with increase in Aeration number the amount of mixing power is reduced at constant Reynolds number. Also, it was observed that increase in Reynolds number enhances power consumption at constant Aeration number.