Performance Comparative Analysis Of Plate-Fin And Tube-Fin Flue Gas Heat Exchangers

Heat exchangers,as thermal energy transfer equipments,wildly used in different areas.It's work performance and operating conditions directly affecting the work conditions of follow-up equipment.In the field of ships,the flue gas heat exchanger can not only plays the role of energy conservation and emissions reduction device,but also the power plant to provide the necessary high-temperature steam and other working substance.Therefore,it is important to compare and analyze the structure and performance of the heat exchanger,and provide the corresponding reference for the design of the heat exchanger.(1)According to the corresponding concept and characteristics of the heat exchanger,various types of heat exchangers were classified.This paper study the most common form of expanded surface heat exchanger,and introduces the research status and possible development trend in experimental correlation,work material,processing techniques and research theories.(2)According to the corresponding calculation standard,this paper introduces the calculation process and calculation formula of the average temperature difference method and the corresponding parameter selection in the calculation of the two heat exchangers.Then according to the smoke emission characteristics and heat exchanger design index of a certain type of low speed diesel engine,considering the design standard and design experience,this paper designs a total of nine different structures of the heat exchanger.(3)In this paper,a variety of heat transfer structures under the same volume are simulated numerically.In the simulation of the tube-fin heat transfer structure,the physical model is established according to the simplified structure of the heat exchanger.Considering the large number of fins and the complexity of structure,a simplified mean is used.Depending on the periodicity and symmetry of the flow field structure,a repeating unit structure is chosen.According to the periodic and symmetry of the flow field structure,this paper chooses a repeating unit structure to calculate the flow of the fluid in each section.Assuming that the flow and heat transfer conditions of the fluid in each section are the same,the overall heat exchanger is calculated.In the simulation of the plate-fin heat transfer structure,since the flow field structure of each unit is very simple,the existing fluid mechanics theory and thermodynamic theory can describe the fluid flow and heat transfer characteristics accurately,so a relatively rare method is used in the overall simulation of heat exchanger.In this paper,the heat exchanger model and the porous media model are introduced and used to calculate the heat transfer characteristics and resistance characteristics of the fluid,and the simulation results of the whole structure are obtained.(5)Analyzing the designing scheme of the same index and the results of checking calculation and simulation calculation in the same volume,and comparing the heat transfer and resistance characteristics of various heat transfer structures,this paper takes into account the various factors,then gives the advantages and disadvantages of various programs and areas of application.