CFD Simulation of Bubbling Process in Nitric Acid Solution in a Bubble Column

Bubble column is a commonly used multiphase reactor. Owing to the complicated nature of its flow structure, computational fluid dynamics has frequently been used as a useful instrument for studying the fluid mechanics in a bubble column. However, most of the previously studied systems are air-water system, while air-nitric acid solution system is rarely reported. In the present study, the differences in bubble size distribution of pure water and 1 mol/L nitric acid in the bubble column were observed through experiments. The bubble size was found to be smaller than that in water when the liquid phase was nitric acid. According to the actual situation, the bubbling process of nitric acid solution was successfully simulated by adjusting the coalescence factor of the bubble coalescence model (deviation less than 10%). Meanwhile, it was observed by simulation that the axial time-averaged liquid velocity distribution in nitric acid solution was flatter than that in water under the same gas flow rate.