Study On Quantitative Detection Of Pipeline With Infrared Based On Transient Temperature Field Model

Pipeline transportation has the advantages of high efficiency,safety,economy,easy control and management,and is widely used in industrial production.Pipeline corrosion defect detection is of great significance for ensuring safe production and economic operation.In view of the existing detection methods of corrosion pipelines,such as low detection efficiency,poor precision and complicated operation,this paper studies the quantitative detection technology of defective pipelines.The main work is as follows: 1)Based on the heat conduction theory and the separation variable method,the transient temperature field model of the pipeline is established.Fluent simulation is used to simulate the temperature field change when the hot fluid is introduced into the variable diameter pipe.The temperature change curve of the pipe surface before and after the variable diameter and the axial temperature distribution of the pipe surface are extracted respectively.The simulation results are compared with the transient temperature field based on the pipeline.The calculation results of the model show that the model error of the pipeline transient temperature field is large at the inlet section and the variable diameter of the pipeline.2)A model correction method based on least squares fitting is proposed.Based on the analysis of the error axial distribution of the pipeline transient temperature field model,the temperature transient curve at the midpoint of the defect is extracted and fitted by least squares method.Determine the relationship between the correction factor and the fluid parameters and pipeline defects,and bring it into the original mathematical model to achieve the correction of the transient temperature distribution model at the midpoint of the pipeline defect,and improve the accuracy of the model calculation at the midpoint of the defect.3)Proposed a quantitative calculation method for pipeline defects based on enhanced fireworks algorithm.The problem of solving the depth of defects is transformed into the problem of minimizing the error between the calculated temperature and the actual temperature.According to the modified transient temperature function at the midpoint of the defect,the enhanced fireworks algorithm is used to calculate the depth of the pipeline defect,and the effectiveness of the algorithm is verified by an example.4)Built a pipeline defect detection platform based on infrared thermal image.The quantitative detection and analysis results of pipeline defect depth indicate that the proposed infrared defect depth detection algorithm based on pipeline transient temperature field model is feasible.