Numerical Simulation Of Shell And Tube Heat Exchanger Based On Thermal-Fluid-Solid

Shell and tube heat exchanger has been widely used in power energy field,because its good adaptability on different environment,big tolerance of pressure and high temperature and high heat exchanger efficiency.During the period of heat exchanging,the tube of heat exchanger have to bear the pressure from flow and the thermal stress from air-flow and waterflow which have different temperature.And because of the assembly process of tube and tube sheet,makes the assembly areas generate fatigue failure lead to tube scrapped.Therefore it is significant to study the fluid flow in the heat exchanger and the thermal stress of the tube while working condition.In this thesis the research base on thermal power turbine low pressure water-feed heat exchanger use ANSYS Workbench build 3D model,analysis the accuracy different types of meshing,try to find a mesh which has independent solution.The steady flow field characteristics of heat exchanger are studied both on water-flow and air-flow.By analyzing the heat exchanger tube,the shell flow field,the temperature field and the pressure distribution,the numerical simulation of the effect of the baffle on the gas spoiler is carried out and the reasons for the relative velocity of the fluid from the backflow side of the baffle analysis.By comparing the numerical simulation results with the theoretical values,the accuracy of the model and the software calculation method is verified.The effects of steam and cold water on the heat transfer performance of heat exchangers under various operating conditions were discussed.The temperature of the fluid in the flow field is loaded into the solid surface of the heat exchanger to obtain the steady-state and transient temperature field of the heat exchanger model,and then the distribution of the temperature between the walls and the heat exchanger from the beginning Work to the heat transfer balance of the heat transient heat transfer process.Finally,the multi-field coupling method is used to load the calculation results of the flow field and the temperature field into the heat exchanger structure calculation module to study the effect of thermal fluid-solid coupling on the stress distribution,structural deformation,fatigue life and material safety factor.The results show that the thermal stress generated by the temperature field is the main cause of the stress in the pipeline,and the influence of the flow field on the stress distribution of the pipeline is relatively small.And the location of thermal stress concentration in the pipe and tube plate junction and pipe and baffle with the Department.Through the analysis of the causes of the above thermal stress,the paper puts forward the appropriate improvement scheme,improves the transition between the tube plate and the pipe,designs the chamfer between the pipe and the pipe plate,increases the relative wall thickness of the pipe and improves the temperature transfer,The difference between the thermal expansion between the pipe and the tube is reduced.Compared with the original simulation,the improved model reduces the maximum stress caused by the temperature difference of the pipeline,and verifies its effectiveness.Based on the study of the interaction between the multi-physics field of the heat exchanger,the flow field,temperature field,numerical simulation of the results and the improvement of the structure under the condition of the heat exchanger are realized,which can provide reference for the design and test of the heat exchanger...