Electrical capacitance tomography (ECT) has been developed for imaging permittivity distribution of two-phase flows in a pipe or vessel with high temporal resolution. The spatial resolution of ECT is relatively low due to its soft-field, ill-posed, and ill-conditioned nature. So far, there is no comprehensive analysis of the spatial resolution of ECT for complex two-phase flows. To assess the merits of ECT systematically, 2-D modeling is carried out based on fluid-field and electrostatic-field coupling simulation for liquid–solids two-phase flows. The real permittivity distribution and the corresponding capacitance measurements can be obtained simultaneously. The effect of the number of electrodes, the mesh used for reconstruction, and the initialization method for the Landweber iteration algorithm on image quality are investigated. In terms of the correlation coefficient between the reconstructed permittivity distribution and the real permittivity distribution obtained from the coupling simulation model, the accuracy and the stability of reconstructed images are quantitatively evaluated. Furthermore, the sensitivity matrices and point spread functions calculated without capacitance measurements are used to compare the performance of ECT sensors and validate the results with capacitance measurements from the coupling simulation. The two methods, with and without capacitance measurements, are used to evaluate the change in spatial resolution of ECT with a different number of electrodes.

中文翻译：

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基于耦合仿真的电容层析成像空间分辨率研究

电容断层扫描 (ECT) 已被开发用于以高时间分辨率对管道或容器中的两相流的介电常数分布进行成像。ECT 的空间分辨率由于其软场、不适定和病态性质而相对较低。到目前为止，还没有对复杂两相流的ECT空间分辨率进行综合分析。为了系统地评估 ECT 的优点，基于液固两相流的流体场和静电场耦合模拟进行了二维建模。可以同时获得实际介电常数分布和相应的电容测量值。研究了电极数量、用于重建的网格以及Landweber迭代算法的初始化方法对图像质量的影响。根据耦合仿真模型得到的重构介电常数分布与真实介电常数分布的相关系数，定量评价重构图像的精度和稳定性。此外，在没有电容测量的情况下计算的灵敏度矩阵和点扩展函数用于比较 ECT 传感器的性能，并通过耦合仿真的电容测量来验证结果。使用和不使用电容测量的两种方法用于评估具有不同电极数量的 ECT 空间分辨率的变化。定量评估重建图像的准确性和稳定性。此外，在没有电容测量的情况下计算的灵敏度矩阵和点扩展函数用于比较 ECT 传感器的性能，并通过耦合仿真的电容测量来验证结果。使用和不使用电容测量的两种方法用于评估具有不同电极数量的 ECT 空间分辨率的变化。定量评估重建图像的准确性和稳定性。此外，在没有电容测量的情况下计算的灵敏度矩阵和点扩展函数用于比较 ECT 传感器的性能，并通过耦合仿真的电容测量来验证结果。使用和不使用电容测量的两种方法用于评估具有不同电极数量的 ECT 空间分辨率的变化。