Variable-diameter ECT clamp-on sensor

This paper proposes a novel variable-diameter electrical capacitance tomography (ECT) clamp-on sensor specifically designed for the detection of load-bearing columns. The sensor allows for the flexible adjustment of electrode widths to meet measurement requirements for different sensor diameters, thereby overcoming the limitations of conventional ECT sensors, which are typically invariable in size and structure and not universally applicable. Each variable-diameter ECT electrode consists of two sub-electrodes, with one end of each sub-electrode affixed to a flexible circumferential base, whose width can be adjusted according to the sensor diameter. The two sub-electrodes combine to form a stable electrode-to-gap ratio (EGR) that remains consistent regardless of the sensor's diameter, thereby ensuring that changes in diameter do not affect the sensor capacitance under a consistent flow pattern. The imaging effectiveness of a 9-electrode variable-diameter ECT clamp-on sensor was verified by simulation and experiment.