| Annealing is one of the most important heat treatment process in cold rolled strip production, the most important role of intermediate annealing in cold rolling process is to make highly hardened metal soften and realize the recrystallization. Full hydrogen bell type annealing furnace stands for the advanced technology of annealing equipment. In the development process, it has experienced from the traditional bell type furnace to nitrogen hydrogen bell type furnace, and then from nitrogen hydrogen bell type furnace to full hydrogen bell type furnace, which make bell type furnace meet various kinds and high quality requirements in steel industry.In this paper, internal and external heat transfer model of full-hydrogen annealing furnace have been analyzed comprehensively, and heat transfer mathematical model of full-hydrogen annealing furnace by the center of steel coil heat transfer mathematical model was built.1. Steel coil temperature field calculation model:taylor series expansion method had been applied to establish the discrete equation of internal nodes and to establish the discrete equation of boundary node based on the heat balance method on the basis of specific analysis for the control equation of steel coil Combined with the internal node and the boundary node equation, the steel coil heat conduction equations was converted into matrix form and using the chasing method to solve it, which lay a foundation for calculating internal temperature field of steel coil.2. The inner cover and the protective gas model:the main forms of steel coil energy exchange are energy exchange between protective gas of inner cover and steel coil, through establishing flow model of protection gas for material chamber space, protective gas velocity of different position can be solved, which provide a basis for calculating convective heat transfer coefficient. The inner cover is not only the intermediate carrier for energy exchange between inside and outside of inner cover, but also the premise of safety working for full-hydrogen annealing furnace, it is necessary to establish temperature field calculation model of inner cover in order to realize the coupling of internal and external temperature field.3. Mathematical model of heat transfer out of the cover:the logic relation of simulation calculation emulator in the anneal process of full-hydrogen annealing furnace is exploited through establishing the solution and control model of furnace gas, the temperature field model of heating cover, the temperature field model of cooling cover, the temperature field model of cooling medium in the outside of inner cover and the coupling of internal and external temperature field for inner cover by temperature field model.Dynamic link library is the best bridge of numerical transmission and operation between VB and MATLAB, M-documents Compiled into DLL documents that could be used by VB and so on. It could achieve the mixed programming between VB and MATLAB, and achieve the off-line prediction platform processor and solver links in the anneal process of full-hydrogen annealing furnace. Illustrating for the use of this platform and analyzing the change of temperature field of steel coil in different phases and the difference between stack, external environment and technologic requirement, analyze the anneal process of full-hydrogen annealing furnace, then verify the accuracy of the platform. |
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