Performance Simulation Of Corrugated With Twist Tape Based On The Core Flow Principle

Heat exchangers are widely used in petrochemical industry,metal smelting,mechanical processing and manufacturing,power engineering,aerospace and other fields as heat exchange backup.This paper mainly analyzes the flow and heat transfer performance of shell-and-tube heat exchangers,and studies the effects of changes in the structure of the twisted strip on heat transfer and flow characteristics.The heat transfer enhancement capability of notched twisted tape structure and new combined twisted tape structure in corrugated tube is numerically calculated by using simulation software.In this paper,a comprehensive evaluation index of heat transfer performance was established,and the effects of twisted tape inserts with different geometrical structures on performance evaluation indexes such as Nusselt number and Fanning friction coefficient were analyzed.The optimal combination of different structures is obtained by analyzing the effects of different geometric structures on the corrugated tube with twisted tape.The geometric parameters of twisted tape with the best heat transfer enhancement effect are obtained by comprehensive analysis of the simulation results.By comparing the simulation results of CT-NTT,and by comparing the changes of Nu,f,PEC and entropy production,the advantages and disadvantages of three kinds of notched twisted tapes in enhancing heat transfer performance in corrugated tubes are analyzed.The results show that for V-type and U-type notched twisted tapes,the comprehensive heat transfer performance of corrugated tube is superior to that of typical twisted tapes,while the comprehensive performance of circular perforated twisted tapes is reduced to a certain extent.The comprehensive comparison shows that,within the scope of the study,the comprehensive performance of Vcut-1 structure twisted tape is the most obvious improvement.A new type of combined twisted tape structure is established.The parameters of twisted tape edge number,spacing ratio and deflection angle are mainly analyzed.The turbulent flow of water and laminar flow of high viscous oil in a corrugated tube are simulated respectively.By changing the values of three kinds of parameters,the heat transfer performance,resistance performance and comprehensive performance of bellows were observed and compared.The variation trend of performance with parameters is obtained,and the optimal structure is obtained in the research scope.The mechanism of the influence of the new twisted tape structure on the flow and heat transfer process of CT-CTT was analyzed.The effects of the number of twisted tape edges,the spacing ratio and the deflection angle on the velocity field,temperature field,pressure field,TKE and TED of the tube were compared.It is found that the number of twisted tape edges has the greatest influence on the overall performance of the pipe,while the effect of deflection angle is relatively weak.Based on the research results of the new combined twisted tape structure,a new combined twisted tape support tube bundle model was established,and the heat transfer and flow process in shell side was studied.The comprehensive performance evaluation index,Nusselt number and friction coefficient of shell side heat transfer enhancement were investigated.The effects of common twisted tape and new combined twisted tape as tube bundle support on shell-side properties and properties were compared.Through the study of streamline,velocity vector,temperature,pressure,TKE and TED,the influence mechanism of combined twisted tape structure on shell side heat transfer process is obtained.The flow and heat transfer in the lower shell side of different Re are compared,and the influence of flow velocity on the shell side performance is analyzed.