Study On Boundary Element Method For Inner Wall Defect Evaluation Of High Temperature Steelmaking Converter

High-temperature steel-making converters,due to long-term operation in harsh working environments such as high temperature,high pressure and corrosion,can easily lead to damage or shedding of the inner wall of the converter,resulting in internal equipment failures,which can lead to safety accidents.Therefore,the detection of the inner wall defect shape of high-temperature steel-making converters plays an important role in safe production.The current non-destructive testing method is difficult to directly detect the inner wall of the high-temperature steel-making converter in operation.Generally,the steel-making converter is periodically shut down for inspection and maintenance,and the converter shutdown during the test period brings huge economic losses to the steel mill.In this paper,by studying the inverse heat conduction problem of the inner wall defect shape of the high temperature steelmaking converter,a boundary element method for detecting the inner wall defect of the high temperature steelmaking converter based on the inverse heat conduction mechanism is proposed.Based on the use of infrared scanning temperature measurement technology to obtain real-time temperature and heat flux data on the outer wall of the steel-making converter,a mathematical model for defect detection on the inner wall of the high-temperature steel-making converter based on the inverse heat conduction mechanism is established.The idea,combined with the optimal control theory,turns the solution of the inverse heat conduction problem into the solution of the three problems of the positive problem,the accompanying problem and the sensitivity problem,and uses the boundary element method to discretely solve these three problems to obtain high temperature steelmaking Boundary shape of the inner wall of the converter,so as to realize online detection of inner wall defects of the high-temperature steel-making converter.Compiling the boundary element algorithm to realize the numerical calculation of the mathematical model,compared with the finite element method and other methods,the boundary element algorithm has the outstanding advantages of reducing the number of dimensions,less input data,and high calculation accuracy.Based on the proposed boundary element method for evaluating the inner wall defects of the high-temperature steel-making converter,a numerical simulation calculation was conducted to analyze the influence of the number of boundary elements,the shape of the boundary to be detected,and the random measurement errors on the results of the boundary element method.The effectiveness of the proposed boundary element method,and this method can better restrain the amplification effect of the inverse heat conduction problem on the measurement error.