Study On Heat Transfer And Fluid Flow Of Falling Liquid Reboiler

The thermal instability of the heat sensitive material brings great difficulties to the distillation operation.In order to solve the problem of distillation of heat sensitive materials,this paper presents a new type of falling liquid reboiler which is suitable for heat sensitive material.And simulation study on heat transfer in falling liquid tube and experimental study on fluid flow distribution among falling liquid tubes are carried out.In the study of heat transfer enhancement in liquid falling tube,this paper used ANSYS fluent 14.5 to simulate the flow and heat transfer on different torsion of the whole inset continuous twisted tape,half inset continuous twisted tape and whole inset spaced twisted tape heat transfer enhanced tube and smooth tube without insert under Reynolds numbers 10000~160000.And analyzed the resistance coefficient and comprehensive performance PEC.Research shows: Insetting twisted tape can disturb the fluid,which can effectively enhance the heat transfer process.And the smaller the twist rate is,the stronger the heat transfer enhanced ability is,but the flow resistance will also increase.The comprehensive performance of half insetting continuous twisted tube is better than the whole insetting continuous twisted tape tube;The tube with continuous twisted tape inset in the first half perform the best comprehensive ability on heat transfer enhancement,and PEC is more than 1 and can reach 1.08~1.12;The enhanced heat transfer performance of the tube with spaced twisted tape inset in the whole course is closed to the tube with continuous twisted tape inset in the first half,and PEC can reach 1.09~1.12.In the study of the flow distribution among falling liquid tubes,this paper investigated the effect of flow distribution adding different specifications of the conical diversion under different flow rate.And non-uniformity coefficient is used to characterize the uniformity of flow distribution.Research shows: Adding appropriate conical diversion is beneficial to the uniform distribution of the flow.The cone angle,bottom diameter and installation position are important parameters affect the diversion effect.It performs optimal diversion effect when the cone angle is 120 degrees,the bottom diameter is 0.5 times to the inside diameter of the head,and the installation location away from the feed inlet distance is 0.1 times to the total head height,when the non-uniformity coefficient is reduced by 53.2%?65.5%.