Abstract:In order to study the effect of turbulence pulsation on the operation of bioreactor, a gas-liquid two-phase flow model was constructed and verified for a vibrating grille reactor with zero time-averaged velocity. The numerical simulation of gas and water flow in the reactor was carried out with the help of Fluent software, and the relationship between turbulent fluctuation intensity and gas holdup, oxygen transfer coefficient and Reynolds stress under ten working conditions was obtained. Based on the physical and chemical data of biofilm, the effect of turbulent pulsation intensity on biofilm growth was analyzed. The results show that increasing turbulent pulsation can effectively increase the gas holdup and oxygen transfer coefficient in the reactor and promote the high efficiency mass transfer between gas and liquid phases. For the vibrating grille bioreactor used in this study, when the turbulence intensity q<2.7 cm/s, the biofilm thickness and density increase with the increase of turbulence intensity, when q>2.7 cm/s, the Reynolds stress plays a significant role, the biofilm becoming thinner and denser gradually. The biofilm growth and pollutant removal effect is the best when the turbulence intensity q=3.4~4.8 cm/s. This study can provide a reference for the design and operation optimization of the bioreactor.