Abstract:

Gas-solid two-phase flow is prevalent in fields such as petroleum, chemical engineering, nuclear energy, environmental, and biomedical engineering. Precise phase fraction measurement is vital for system safety and efficiency. This paper aimed to develop an online measurement system based on the multi-frequency electrical capacitance method to enhance the accuracy and anti-interference capability of gas-solid phase fraction measurement. The system utilized an FPGA to control a DAC module to generate multi-frequency excitation signals, combined with a C/V conversion circuit and DPSD algorithm to extract real and imaginary parts of the signal. Experiments simulated gas-solid two-phase conditions using acrylic rods of different diameters in an acrylic pipeline, measuring within a frequency range of 500kHz to 1MHz. The results confirmed the system's ability to accurately measure phase fractions, exhibiting strong stability and interference resistance. This research offered an efficient electrical approach for real-time gas-solid flow measurement, with broad potential applications in industrial processes and biomedical monitoring.

Key words: multi-frequency electrical capacitance detection, phase fraction, online measurement, gas-solid two-phase flow, circuit design

摘要：

气固两相流广泛存在于石油、化工、核能、环境工程及生物医学工程等领域，其相含率的精确测量对系统的安全性和运行效率至关重要。本文开发了一种基于多频电容法的在线检测系统，以提高气固相含率的测量精度和抗干扰能力。系统通过现场可编辑门阵列（FPGA）控制数模转换器（DAC）模块生成多频激励信号，结合电容/电压（C/V）转换电路及数字相敏检波（DPSD）算法实现信号的实虚部信息提取。实验在有机玻璃管道中通过不同直径的有机玻璃棒模拟气固两相情况，在500kHz~1MHz频率范围内进行测量，结果表明该系统能够准确测量不同相含率，并具备良好的稳定性和抗干扰能力。该研究为气固两相流的在线测量提供了一种有效的电学方法，可广泛应用于工业过程以及生物医学领域的相含率实时检测。

关键词: 多频电容检测, 相含率, 在线测量, 气固两相流, 电路设计