Structure Design And Thermal Coupling Analysis Of Coaxial Combination Heat Exchanger

Heat exchanger is a necessary equipment which is widely uesd in mechanical,chemical,metallurgy and other industries.The traditional single arch shell and tube heat exchanger has the disadvantages of low heat exchange efficiency,easily scaling and poor compression capacity,which is hard to meet the production demand.Therefore,it is necessary to develop a new type of heat exchanger.With the development of enhanced heat transfer and calculation of heat exchanger,heat exchanger has been continuously improved and developed.Based on the characteristics of shell-tube heat exchangers and spiral structures,a new type of coaxial combination heat exchanger was proposed in this paper.Based on the structural design of coaxial combination heat exchanger,its heat exchanger characteristics were studied by numerical simulation and experiment and the influence of the coaxial heat exchanger structure on the heat transfer characteristics were studied also.Finally,the heat transfer characteristics of the coaxial combination heat exchanger and the existing spiral plate heat exchanger in a coking plant are compared experimentally.The main contents of this paper are as follows:(1)Based on the advantages and disadvantages of the traditional single arc-tube-shell heat exchangers,the concept of multilayer coaxial heat exchanger tube coaxial combination assembly is proposed.Design the structure of single coaxial heat exchanger tube,shell,shell cover,tube plate and supporting plate.Complete the check for heat exchanger area.(2)The structural model and fluid model are established and completed thermal coupling.The flow structure and heat transfer characteristics of the coaxial combination heat exchanger are analyzed by the loosely coupled method.The influence of mass flow of cold fluid under the conditions of 1.0kg/s,1.5kg/s,2.0kg/s,2.5kg/s and 3.0kg/s.The results show that the pressure drop of the inlet and outlet of the cold fluid is greatly influenced by the mass flow rate of the cold fluid.Under the five conditions,the pressure drop of the cold fluid increases with the increase of the mass flow of the cold medium,while the pressure drop of the hot medium decreases first and then increases.(3)The influence of the spiral winding,the length of spiral and the diameter of the pipe on the heat transfer characteristics are studied by JF method.The results show that the spiral wind Clock wise alternate with Counter Clock wise,increase the length of the spiral and the volume have a good heat exchanger effect.(4)A comparison between coaxial combination heat exchanger and spiral plate heat exchanger was designed.The heat transfer characteristics of a coaxial composite heat exchanger and a spiral plate heat exchanger are studied,the results show that in the same flow condition heat transfer efficiency of coaxial combination heat exchanger is 1.1~1.2 times than spiral plate heat exchanger.