摘要
提出了改进的交流法微弱电容检测电路,对相敏解调器的输入正弦信号作带通滤波处理,以提高检测精度和稳定性。为了简化数据采集系统,提出了单检测通道的电容层析成像硬件架构,设计了适用于单检测通道电容层析成像的12电极T型电极开关阵列,并可以升级为16电极系统。为了克服单通道检测速度低的缺陷,改进检测电路以缩短C/V转换时间。将单检测通道电容层析成像系统应用于煤粉气力输送的过程检测中。重建图像显示,在输送固相体积浓度由0.15增加到0.4的过程中,水平管道气固两相流的流型由层流变为均相流,稳定后又恢复到层流状态。
An improved AC-based circuit for weak-capacitance measurement is presented. A band pass filter is adopted before the phase sensitive demodulator to improve the accuracy and stability. To simplify the data acquisition system, an ECT hardware structure of single channel capacitance measurement is introduced, and then 12-electrode switch arrangement of T type, which is suitable for ECT of single measurement channel, is designed. In addition, the 12-electrode system can be upgraded to 16-electrode ECT easily. To overcome the disadvantage of low speed, a measurement circuit is developed to shorten the time of C/V conversion. The ECT system with single measurement channel is applied to the process measurement of pneumatic conveying of pulverized coal. The reconstructed image demonstrates that the gas/solid flow pattern in horizontal pipeline turns from stratified flow to homogeneous flow when the solid volume concentration of pneumatic conveying changes from 0.15 to 0.4, and returns to stratified flow when the flow gets stable.
出处
《仪器仪表学报》
EI
CAS
CSCD
北大核心
2010年第1期132-136,共5页
Chinese Journal of Scientific Instrument
基金
国家自然科学基金重点项目(50836003
5090612)
国家重点基础研究专项经费(2010CB227002)
南京工业大学学科基金
教育部博士点新教师基金(200802861005)资助项目
关键词
电容层析成像
单检测通道
气力输送
微电容检测
electrical capacitance tomography
single measurement channel
pneumatic conveying
weak-capacitance measurement
