Ultrasonic Field Simulation And Experimental Investigation Of Fouling Pipeline Based UTDR

Among the process of industry heat-exchange,fouling cauces great cost and low efficiency.Because its occurring conditions,factors and mechanism are variable and complex,it is very difficult to develop a precise mathematical model to make the overall description.Accordingly,it is necessary to apply artificial intelligence to the on-line fouling monitoring technique.Although many fouling monitoring researches and methods of heat exchange equipment have been carried out,there is still no detection accuracy in the process of fouling formation and there is no efficient,convenient and complete testing process to quantify the degree of fouling.Ultrasonic technology used in the detection of fouling in the membrane separation of pollution has been a lot of research,and for a variety of heat transfer equipment in the pipeline dirt detection,it is clear that ultrasonic detection of pipe fouling is difficult due to echo complexities and many other factors have not fully been identified in existing studies.In this paper,we first analyze and summarize the propagation characteristics of ultrasonic field in single-layer pipeline,taking the dynamic experiment of the heat transfer equipment of the Engineering Laboratory of Energy Conservation& Measure-Control Technology of Northeast Electric Power University as the research background.Based on fluid-solid coupling,the finite element modeling of the deformation of the pipe body and the flow pattern of the fouling water is carried out during the ultrasonic time domain reflection(UTDR)testing,analysis of the main factors affecting the thickness of the fouling during the ultrasonic detection.Followed by the actual detection of noise interference,affect the subsequent experimental fouling signal processing.According to the characteristics of the fouling echo signal simulation,a method for noise reduction of heat transfer fouling ultrasonic detection based on complete ensemble empirical mode decomposition(CEEMD)theory is proposed,combined with the characteristics of the autocorrelation function of the noise detection noise,to suppress the pseudo-Gibbs oscillation problem caused by hard threshold and soft threshold noise reduction.The effectiveness and feasibility of the proposed method was validated by simulation testing of a liquid filled fouling pipeline and heat transfer of the pipeline equipment.After noise reduction,the transition time was extracted from the qualitative and quantitative aspects to achieve the accurate detection of fouling thickness,compared with the fouling thermal resistance time series measured by the fouling thermal resistance dynamic simulation automatic detection device,the effect of fouling detectiong is good for the pipeline of heat exchange by UTDR,the numerical simulation results agree with the test results,whichcan reflect the change rule of the fouling thickness during the operation of the heat transfer pipeline.