The detection and evaluation for the internal defection in industrial pipeline based on the virtual heat source temperature field

Industrial pipelines work in high temperature and are corrosive, and this causes corrosion and shedding of the inner walls. Therefore, it is a realistic engineering problem to detect the defect information of pipeline accurately. In the paper, according to the characteristics of pipeline and heat conduction theory, the temperature field is equivalent to a composite model. Utilizing the three-dimensional heat conduction equation, the heat dissipation temperature field model of no-defects pipeline is established. Taking the medium temperature as the boundary condition, the model is solved by variables separation method and Bessel function. Secondly, based on the principle of microelement integration and finite element, considering the uncertainty of the defect boundary, the boundary information is expressed by the geometric variable factors of virtual heat source. And heat source temperature field model is obtained. Then, using the defect radius as the variable, the boundary function of the defect is established. Thirdly, considering the temperature field function and the maximum allowable pressure of the pipeline, the effective temperature evaluation model of pipeline defects is constructed. Finally, using the experiments and the Simulation of Software COMSOL, the feasibility of the pipeline models is verified. The relationship between the defect boundary and the temperature can be analyzed by mathematical methods. Internal defects in pipes are quantitatively analyzed and evaluated. This provides a theoretical basis for ensuring the quality and operation of the pipeline.