| With China's economy entering the "new normal",the steel industry must exert its efforts from the supply side,speed up its own structural adjustment and technological upgrading in order to ensure sustainable development and move towards the "green production" road of low energy consumption.TMCP(Controlled Rolling and Controlled Cooling)is a typical representative of the advanced technology in the field of hot-rolled strip production,it is an effective way to further improve the performance of strip and save alloy elements,and cooling unit is one of the core devices to realize TMCP process.In industrial production practice,considering the difference of hot strip specification and material cooling process path,as well as the cost of production line transformation and other factors,TMCP cooling line mostly adopts the combination configuration of laminar cooling unit and rapid cooling unit.The results show that the cooling capacity near stagnation point is no longer significantly improved when the flow rate of traditional laminar cooling header increases to a certain extent.In recent years,there was many studies on ultra-fast cooling technology and equipment,but the effect of equipment structure parameters on water saving and cooling capacity has rarely been reported.In order to further excavate the performance of traditional laminar cooling equipment and save water as much as possible on the basis of meeting the technological requirements,it is urgent to carry out theoretical and experimental research on optimization of fine analysis parameters of laminar cooling equipment.The research focuses on the heat transfer behavior of laminar cooling interface of hot rolled strip,fine structure analysis of traditional laminar cooling device and simulation software development of laminar cooling process system.Firstly,in order to study the structure characteristics,heat transfer behavior and cooling capacity of laminar cooling unit and rapid cooling unit,a set of physical simulation test platform including water supply system,spray system,heating and transfer system of experimental steel plate,signal acquisition system(flow rate,pressure,temperature)was developed independently.Secondly,using the physical simulation experimental platform and Fluent flow field analysis software,the effects of laminar cooling manifold throttle ring,gooseneck tube structure parameters and laminar cooling process parameters on cooling water flow,water flow state and convective heat transfer coefficient at steel plate interface are analyzed in detail;The structure size parameters of throttle ring and gooseneck tube are optimized and tested under different working conditions;The temperature drop curve at the center of the plate and the temperature field on the surface of the steel plate photographed by infrared thermal imager were fitted to obtain the prediction formula of the cooling influence zone of gooseneck spray water column,and the convective heat transfer coefficient model of the experimental steel plate surface was obtained by inverse calculation.Finally,based on the established model of convective heat transfer coefficient on steel plate surface,the laminar cooling heat transfer process of hot strip is simplified to a onedimensional transient model in thickness direction.The temperature simulation software of the whole laminar cooling process of hot strip is developed by using VB visual programming language,and the simulation calculation of typical working conditions is carried out,the simulation results are in good agreement with the field test data.The research methods and theoretical results also have important guiding significance for the research and development of rapid cooling devices. |
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