Numerical Study On Shell-side Enhancement Of Heat Transfer And Fluid By Swirl Structure

Despite the rapid growth of Chinese economy at this stage and a lot of construction having made great achievements,we paid a huge price,such as resources and the environment having been seriously damaged.The contradiction between the two has become increasingly acute.This situation is caused by unreasonable economic structure and growth mode.So sticking to the clean development,conservation development and security development is the way to achieve economic development faster and better.Heat exchangers are widely used in many engineering fields,such as petroleum,chemical,electrical,medicine,metallurgy,refrigeration,etc.The industry is also energy-hungry.Energy-saving design of heat exchangers for energy conservation has a very significant contributionIn recent years,domestic and foreign experts are studying the transformation of the traditional shell and tube heat exchanger and working to develop a new generation of enhanced heat transfer in order to meet the performance requirements of the shell and tube heat exchanger by different places.The paper focuses on studying the heat transfer enhancement on the shell and tube heat exchanger shell.Through the study of previous helical baffle heat exchanger,this paper proposes a new spiral baffle helical baffle heat exchanger.The research contents of this paper are summarized as follows(1)In this paper,Gambit-the Fluent software pre-processing software is used to establish the physical model and mesh of the helical baffle heat exchanger,while establishing traditional segmental baffle heat exchange physical model for the helical baffle heat exchanger comparison.Four different helix angles,35°,40°,45°and50°,is selected for model building,in order to find the optimal angle of the heat exchanger.(2)The physical model of the Fluent software is used in the numerical calculation.In order to facilitate the calculation,this paper puts forward three kinds of model assumptions.First assuming the inner wall of the heat exchanger tubes and baffles are closely connected,second assuming the fluid is fully developed and export,third assuming bundle temperature is set at room temperature.Imports is set to speed entry.Effects of treatment uses the RNG turbulence model for turbulent flow and heat transfer effect.Velocity and pressure coupling uses Simple algorithms and second-order upwind.Fluid inlet temperature is 30?,and bundle temperature is 70?.(3)Helix angle of 45°helical baffle heat exchanger is selected as a typical to compare with the traditional segmental baffle heat exchanger.Analysis of two heat exchangers' velocity,pressure and temperature fields under three different fluids.Put forward that when the fluid medium is air,oil and water,the helical baffle heat exchanger shell side pressure drop than baffle decreased by 44.1%,47.4%and 43.8%heat exchanger,the heat transfer coefficient under unit pressure drop were increased by 79.3%,52.9%and 47.5%.(4)On the 35°,40°,45 ° and 50° four different spiral angle of the heat exchanger analysis,and the inlet velocity being 1.032m/s,1.5m/s,2.0m/s,2.5m/s and 3.0m/s five,water is used as the working fluid.The results show that when spiral is 45°,heat transfer performance of heat exchanger is the best.The spiral is 35°,40°,45 ° and 50° of the helical baffle heat exchanger unit pressure drop of the heat transfer coefficient than conventional baffle heat exchanger distribution increased 32.1%,40.7%,52.9%and 24.9%.(5)Helix angle of 45°helical baffle heat exchanger is selected as a typical to analyze in different media,namely air,oil and water,and different flow velocity,namely 1.032m/s,1.5m/s,2.0m/s,2.5m/s and 3.0m/s.The unit pressure drop of the heat transfer coefficient as the evaluation standard,draw oil heat transfer effect is the worst,the fluid medium water heat exchanger is best.