油气润滑测试系统中ECT软场效应研究

Research on Soft Field Effect of an ECT in Oil-air Lubrication Testing System Based on COMSOL

电容层析成像系统的传感器具有"软场"特性,即敏感场分布受被测介质的影响。为获得高质量的重建图像,利用COMSOL软件快速求解油气润滑测试系统ECT的灵敏度矩阵,运用COMSOL和MATLAB联合仿真,对该管道内层流和环状流2种典型流型的灵敏度场的软场效应进行分析,并且应用LBP算法和OTSU算法,分别在考虑和忽略软场效应的情况下对2种流型进行图像重建。仿真结果表明,软场效应改变了灵敏度分布;润滑油介质靠近管壁时,检测敏感度较高;采用软场效应改变的灵敏度矩阵进行图像重建,将有效提高重建图像精度。

Electrical capacitance tomography （ECT） sensor has the ＇ soft field＇ characteristic which means the sensitiv- ity distribution is dependent on the permittivity distribution.To obtain high quality reconstruction images ,sensitivity matrix of an ECT used in oil-air lubrication testing system was solved quickly by COMSOL software.The soft field effect on the sensitivity of two typical flow patterns,laminar flow and annular flow ,in the pipeline was analyzed by both COMSOL soft- ware and MATLAB software.Two flow patterns were reconstructed separately by LBP algorithm and OTSU algorithm when the soft field effect was taken into account or not.Simulation results show that the sensitivity distribution is changed when the soft field effect exists, and the detection sensitivity is higher when the lubricating oil is closer to the wall of pipe, and precision of the reconstructed image is improved effectively using the sensitivity matrix changed by the soft field effect.