Research On Heat Transfer Characteristics Of Oscillating Baffle Crystallizer

Multi-shell Passes crystallizer(MSPC)is a new type of continuous crystallization device,which uses cold water switching device to overcome the technical defects of easy crystallization at the tube wall.The numerical simulation method was used to study the heat transfer characteristics of MSPC.The numerical model and physical model were developed.The results show that the temperature change trend of the fluid near the wall of the MSPC is consistent with the temperature change trend of the corresponding wall surface,and the temperature change trend of the fluid inside the tube is stepped.The temperature of the fluid in the MSPC gradually decreases along the positive axis direction.Oscillatory baffled crystallizer(OBC)is a new type of continuous crystallization device.Due to the periodic oscillation conditions and the geometry of the baffle of the OBC,a cyclic vortex is formed in the crystallizer,which enhances the radial and axial mixing of the fluid in the OBC and improves the residence time of the fluid in the crystallizer,It is of great help to the heat transfer effect.Transient numerical analysis of oscillation conditions(amplitude and frequency)effects on the flow and heat transfer in OBC.The numerical model and physical model were developed.Based on the SST k-? turbulence model and user defined function(UDF),an oscillatory flow was introduced into OBC so as to study the synergetic effects of fluid micro-mixing and heat transfer in OBC,and then the evaluation coefficient of PEC was used to evaluate the heat transfer efficiency in OBC.On the basis of transient numerical results,the average fluid velocity,pressure drop and Nusselt number increase with the increase of amplitude and frequency,while resistance coefficient decreases with the increase of amplitude and frequency;the axial temperature in OBC drops in a wavelike model;bigger amplitude and frequency,less time for achieving steady temperature and higher evaluation coefficient,which means better heat transfer efficiency in OBC.The flow characteristics and heat transfer characteristics of OBC were obtained through numerical simulation,which provided theoretical guidance for the design and structural optimization of OBC,and provided a theoretical basis for OBC's crystallization process.