Experimental and simulation investigation of the intermittent gas flooding phenomenon within dynamic gas distribution impeller

A new type of gas-liquid mixing impeller, called the dynamic gas dispersion paddle, has been developed to meet the market demand for large-diameter impeller. The determination of the power number, relative power demand and gas holdup is based on experimental results. Moreover, unstable gas dispersion phenomenon, intermittent gas flooding, occurs in both the experimental and simulation processes. The interaction between the aeration gas from the gas channel and the inhaled liquid across suction port is unfavorable for gas dispersion, as indicated by the simulated gas stream traces. The interaction is considered the trigger for gas flooding. On the basis of the instability mechanism, the impeller has been modified to reduce the gas velocity at the gas channel outlet and shorten the distance between the gas channel outlet and the blade back. Experiments confirmed the elimination of intermittent flooding.