A Shell-and-tube Heat Exchanger Performance Optimization And Vibration Characteristic Analysis

Economic development needs support of energy.As a common equipment of energy recovery and utilization,heat exchanger plays an important role in the national production and living.Thus it’s important to keep the operation of heat exchanger stable and effective so as to make the equipment safe and energy efficient.This dissertation has done a series of experiment and simulation researches on a baffled heat exchanger,to discuss the fluid’s flow and heat transfer conditions.It’s aimed to solve the problems of low heat transfer efficiency,easily induced vibration and serious scaling bundles.The main work of this dissertation is:(1)Measure the baffled heat exchanger size,monitor the working condition,design the experiment plan,carry out the heat exchanger experiment by test bench and obtain the experimental results.(2)Build the finite element model and carry on the simulation by commercial software Fluent under the same experimental working condition.Compare the experiment and simulation results to ensure the simulation correct.(3)Combined the j/f with the field synergy theory and deal with the experimental and simulation data.Reach the conclusion that when Re<500 the performance of the heat exchanger increases rapidly along with the increase of Re,while when Re>500 the rate of the increase slows down.(4)Study the vibration characteristics of the heat exchanger and obtain critical velocity of the resonance.The simulation result shows that longitudinal velocity critical velocity is 10~100 times of the lateral velocity.Research the flow around a circular cylinder by CFD,the result is that the vibration in the direction perpendicular to the velocity is the intensest.(5)A new program of Rodbaffle heat exchanger with circular and square sections has been presented.Investigate the heat exchanger performance by Numerical simulation.The conclusion is obtained that the pressure drop of the Rod-baffle heat exchanger is less than the Baffles heat exchanger.The heat exchange performance of the Rod-baffle heat exchangers is better than the Baffle heat exchanger when Re<500 and the performance is worse than Baffle heat exchanger when Re>500.In all the ranges of the Re,the heat exchange efficiency of Rod baffle heat exchanger is better than it of the Baffles heat exchanger especially the square sections Rodbaffle,which has the best performance.(6)Analyze the influence of the different offset on the square sections of Rodbaffle heat exchangers,obtain the optimization result.The selections of the offset are 76 mm,38mm and 5mm.