Research On Internal Flow And Meat Transfer Enhancement Of Spiral Plate Pile-honeycomb Heat Exchanger

The heat exchanger performance of the heat exchanger has played a very important role in alleviating the shortage of resources.It has become a central issue for domestic and foreign scholars to design new heat exchangers and improve the structure of the traditional heat exchangers.In this paper,there is a new type of spiral plate pile-honeycomb heat exchanger including cylindrical,elliptical and rhombic three kinds of pile-honeycomb structure studying the performance on internal flow and heat transfer of spiral plate heat exchanger.The numerical simulation method was used to analyze the heat transfer enhancement mechanism of the new heat exchanger,and finally a new spiral plate heat exchanger which has better internal flow and heat transfer performance is obtained.The main results of this paper are as follows:First of all,in order to comprehensively compare the heat transfer performance of honeycomb and pile-honeycomb structure,the numerical simulation of honeycomb and pile honeycomb plate heat transfer model was carried out,and the numerical simulation method applied in this study was obtained.According to the flow and heat transfer characteristics of the fluid in the spiral flow channel,the physical and mathematical models of these heat exchangers were established.The RNG k-? model and Re alizable k-? model were selected as the simulated turbulence model.Considering the purpose of this study and the application range of various heat exchanger performance evaluation methods,the paper chose the single performance evaluation method,comparing comprehensively the temperature,heat transfer coefficient,nusselt number and other indicators.Secondly,the cylindrical honeycomb and pile-honeycomb spiral plate heat exchangers were simulated,analyzing and comparing the internal flow and heat transfer characteristics comprehensively from velocity magnitude,vorticity magnitude,turbulence intensity enthalpy,entropy,surface heat transfer coefficient,surface nusselt number.The flow state of the fluid in the pile-honeycomb model was chaotic,the degree of chaos was larger than that of the honeycomb model,and the volatility was strong,which is similar to the characteristics of the tidal fluctuation.The addition of fluid turbulence can effectively enhance the heat transfer capacity and improve heat transfer efficiency.Thirdly,the numerical simulation of the spiral plate heat transfer model of cylindrical,elliptical and rhombic pile-honeycomb structures was carried out,comparing and analyzing the simulation results.It is found that the flow and heat transfer performance of cylindrical spiral plate were worse than those of elliptical and rhombic models,and the flow of elliptical internal fluid was more intense and chaotic.This flow tends to increase the damage and energy consumption of the equipment.Finally,the spiral plate heat exchanger rhombic model was selected as the optimization model.Finally,outlet temperature,nusselt number and surface heat transfer coefficient were used as three indexes for the optimization of the diagonal according to the orthogonal test method,including four factors which are cross diagonal,vertical diagonal,height and inlet velocity.This paper completed orthogonal test design by selecting appropriate levels and orthogonal table.Nine models of model establishment,grid division,boundary conditions and other settings and numerical solution were finished by the engineering software ANSYS Workbench.The flow field and the temperature field obtained after the solution were analyzed.After observing the outlet temperature,nusselt number and surface heat transfer coefficient of the scatter plot and the internal flow chart,it is found that the eighth program is the better program.The results of the nine experimental schemes are analyzed by the range analysis method and the gray relational analysis method,so the accuracy of the numerical simulation results is verified.