Numerical Simulation On Fluid Flow And Heat Transfer Characteristics Of Plate And Shell Heat Exchanger

Plate and shell heat exchanger(PSHE),a new type heat transfer equipment highly efficient and compact structure,which would has a broad application prospect and has been used in engineering fields such as chemical,petroleum,refrigeration and so on.In this paper,by building simplified flow channel models and adopting numerical simulation method,it analyzed the influences of structure parameters and distribution performance of flow at the entrance on the flow and heat transfer performance,and also conducted comprehensive evaluation and optimization.Meanwhile,comprehensive evaluation and optimization design were also carried out.All the research results may have a certain significance for the study and the application of PSHE.Based on the simplified flow channel models,the paper analyzed changers of the distributions of the flow fields,velocity fields,temperature fields and pressure fields with different corrugated angle,corrugated pitch and corrugated height.It could be concluded that the change of structural parameters leads to the mutual transformation of cross flow and tortuous flow.Another conclusion is also available: with the increase of corrugated angle,so the heat exchange efficiency,but the pressure loss increases;with the increase of corrugated pitch,so the heat exchange efficiency,but gradually reduce the pressure loss;with the increase of corrugated height,so the heat exchange efficiency is worse then gradually getting better,the pressure loss is reduced gradually.By using the method of enhancing heat transfer coefficient and the method of unit resistance performance factor for corrugated angle,corrugated pitch,and corrugated height to evaluate the effect of comprehensive performance respectively,it conducted the conclusion as follows: while P and H are certain,smaller ? is much better;while ? and H are certain,greater P is more suitable;while ? and P are certain,smaller H is expected.Moreover,by adopting the uniform design experimentation to test and verify the validity of the comprehensive evaluation,the best optimum analysis was made and the best structural parameter came out.Plate side and shell side of PSHE with single pass were simulated to find the existence of the uneven distribution of flow.The uneven distribution of flow is proved to cause the decrease of heat exchange efficiency and the increase of pressure drop,and shell side is more serious.The uneven distribution of U type was lower than Z type,so it has higher heat transfer efficiency and lower pressure drop,while the uneven distribution has no impact on the shell side.Above all,the optimized methods were also summarized to improve the performance of PSHE.The establishment of the geometric models is on the basis of multi-passes PSHE.By conducting the numerical simulations and calculated the deviations and the relative standard deviation of the mass flow,it analyzed and compared the fluid flow distribution performances of plate side and shell side,and concluded the influences of fluid flow distribution performance on heat transfer efficiency and pressure drop.It could be concluded that there are always uneven fluid flow distribution on both sides,and the plate side is more seriously.In addition,the uneven fluid flow distribution increases with the increase of flow rate and passes,and it also leads to the descending of heat transfer efficiency and the increase of pressure drop.On the whole,on account of the influence of factors such as reflux,the decrease degree of heat transfer efficiency is modest.This part summed up the optimized methods as well,which are similar to single pass PSHE,could provide reference for the related research.