Numerical Simulation Of The Flow Characteristics And Mass Transfer Performance In Ozone Oxidation Bubble Process

Ozone is widely used in wastewater treatment as one of the most effective oxidants and can remove most of the organic and inorganic substances.However,there are disadvantages such as the cost of ozone production is high while the generation efficiency is low.So,it’s important to learn the rising and dissolution process of ozone bubbles quantificationally.In this paper,utilization of the ozone is focused and systematic simulations are carried out.A computational model for an ozone oxidation reactor was proposed to represent,simulate and predict the ozone bubble rising process.To study the instant effects between the flow,mass transfer process and ozone oxidation reaction,the coupling modeling is chosen to calculate the ozone oxidation bubble process.The model is validated with the experimental data from literatures and show great agreements.Characteristics like bubble shape,equivalent diameter,velocity and mass transfer coefficients are obtained through postprocessing and data fitting.The verified model is used to simulate and optimize the effect of operating conditions and equipment structure.Inlet gas velocity,initial ozone concentration and contaminated solution are studied specifically as operating conditions,while gas distributor and double gas inlets are learnt for the feeding mode.It is found that continuous ozone input can influence the bubble motion.With effects of adjacent bubbles,rising velocity of the target bubble is increased.Ozone’s mass transfer performance is affected by the inlet gas velocity and initial ozone concentration,and the influence rules are not the same for the bubble group and single bubble.Relationship between the inlet velocity,the initial concentration and the corresponding rising height is presented to optimize the design of ozone oxidation dyeing wastewater treating process.Foam material can be used as gas distributor and the bubble characteristics are affected by the gas distributor through the bubble’s formation process.In the case of two gas inlets,coalescence between the ozone bubbles happens when distance between the two inlets is less than 50 mm.Compared with single inlet,the oscillation amplitude is lager while the vertical velocity is smaller of bubbles generated by two gas inlets,however,mass transfer performance is similar within effects of the above factor.