CAJ | 학술논문

针对电容层析系统中的微小电容的检测问题，设计了一套以AD7746为核心芯片的微小电容在线检测装置，该装置是以八电极圆形管道为模型，通过电容数字转换技术（ CDC ）对微小电容进行检测。与传统的AC电桥测量装置相比，电容检测电路得到简化；与充/放电原理电容检测相比，不存在电荷注入和零点漂移，提高了电容检测系统的稳定性和精确性。同时利用有限元计算了灵敏度，使用线性反投影法（ LBP）进行成像，该装置对实际的两相流在线检测具有非常重要的现实意义。
침대전용층석계통중적미소전용적검측문제，설계료일투이AD7746위핵심심편적미소전용재선검측장치，해장치시이팔전겁원형관도위모형，통과전용수자전환기술（ CDC ）대미소전용진행검측。여전통적AC전교측량장치상비，전용검측전로득도간화；여충/방전원리전용검측상비，불존재전하주입화영점표이，제고료전용검측계통적은정성화정학성。동시이용유한원계산료령민도，사용선성반투영법（ LBP）진행성상，해장치대실제적량상류재선검측구유비상중요적현실의의。
Aiming at the small capacitance detection , a AD7746 chip-cored capacitance tomography system was developed , which takes the eight-electrode round tube as a model , and applying CDC technology to detect small capacitance .Compared with the conventional AC bridge measurement device , the capacitance detection circuit is simple; and compared with charge/discharge capacitive sensing principle , no charge injection and zero drift can be found , this improves measurement stability and accuracy; and the finite element algorithm used can benefit the improvement on sensitivity; and the linear back projection can be applied in the image formation .This device has important practical significance on the on-line inspection of two-phase flow .