Study On Induction Heating Process Modeling And Temperature Control Of Steel Pipe Coating Crafts

Induction heating technology has gradually become one of the conventional heating methods in industry,it holds the features of the fast eddy heating,high efficiency and no pollution.Coating process of steel pipe with Induction heating involved the problem of temperature control,which features nonlinearity,multi-variable,time-delay and strong-coupling.Thus,an effective and feasible modeling method is needed to predict and control the process.This thesis' s main research contents are as follows:(1)Modelling and analysis of the steel pipe induction heating based on 3D finite element method.Focus on the problem that moving-piece has a long computation time in 3D finite element numerical simulation of the steel pipe induction heating,an improved method with the movement of billet is proposed.Firstly,the movement of the loads is used to replace the relatively movement between the coil and the billets.Contrasting the traditional movement way of the billet,the method holds features of fast speed and high precision.Secondly,a 3D temperature field modeling is carried out by using the improved motion method and the traditional finite element method.Finally,an improved 3D finite model was used to simulate the facts,so as to analyze the distribution and variation of the temperature field in the induction heating process of the steel pipe.With the comparison,the improved model shows faster speed and highly prevision.(2)Establishment and verification of the temperature prediction model of the process of the steel pipe induction heating.As for solving the problem of temperature prediction control in the field conditions,the temperature prediction model based on finite element method is established and applied.With the meshing experience from the FEM algorithm,the steels are broken down into several pieces.Then the analysis of the temperature field of every piece is carried out and a reassembled temperature prediction model is established.Finally,the simulation and analysis of practice cases validate the rationality of the model and also show that it has some errors in the head position of steel pipe.(3)Adjustments and applications of the temperature prediction model of the process of the steel pipe induction heating.Analysis of the prediction model based on the mechanism found that the prediction model can be adjusted from the aspects of the power conversion coefficient,the initial temperature coefficient matrix and the duty ratio of steel pipe.This thesis adjusts these three factors by GA(genetic algorithm).From the result analysis,adjusted model has higher precision and greater applicability,which can be used in the actual control process.As for solving the problem of temperature deviation in the actual production process,GA is used to adjust the optimal control powers,with the requirement that the process temperature reaches the target temperature as much as possible.