Oscillatory Flow Reactor Flow Characteristics

We report experimental observation on flow patterns and residence time distribution measurements for oscillatory flow reactor where periodic baffles and fluid oscillation may be present.The flow visualization experiments using particle image velocimetry provide a deep insight into the mixing and flow pattern modification over a range of oscillation amplitude and oscillation frequencies. The photographs can be divided into three kinds: (1) at higher Strouhal number, i.e.- 2.65-7.96, the photographs show that there is no eddy between the battles and laminar flow in the central section of the tube. (2)at lower Strouhal number, i.e.- 0.796-1.989 and Reynolds number lower than 2700, Eddies are successively generated at the tips of the baffles and then ejected into the fluid. (3) at lower Strouhal number, i.e.- 0.796-1.989 and Reynolds number higher than 2700, eddies are randomly distribution of any detectable boundary layer between the battles.The experimental results show that controlled mixing and well-difined residence time distribution can be obtained. The flow patterns can be divided into three kinds on different oscillatory amplitude and oscillation frequencies: (1) at higher Strouhal number, i.e.- 2.65-7.96, a single parameter axial dispersion coefficient is determined and it is show that dispersion using oscillatory flow in baffled tubes can be less than axial dispersion for a turbulent net flow.(2) at lower Strouhal number, i.e.- 0.796-1.989 and Reynolds number lower than 2700, a model using tanks in series with cavity backmixing and percentage of volume is developed to analyse the concentration curve. (3) at lower Strouhal number, i.e.- 0.796-1.989 and Reynolds number higher than 2700, another model using tanks in series with cavity backmixing, banks backmixing in cavity and percentage of volume is introduced. The computed results of flow models answer for the experimental results of residence time distribution measurements well. It show that the solution dealing with the flow patterns modification is viable.