基于静电传感器的气固两相流流动参数特性研究

Study on the Flow Parameter Characteristics of Gas-Solid Two-Phase Flow Based on Electrostatic Sensor

使用内嵌环形电极进行静电法气固两相流测量时,测量信号不仅仅包含静电感应电荷信息,还包含带电颗粒与管壁碰撞转移电荷信息。由于静电感应产生的信号上下波动幅值相等,时域均值为0。而由于颗粒管壁碰撞产生的转移电荷信号,当管道材质为不锈钢,电荷总体带正电,时域平均值为正值。通过实验对测量电路输出信号进行分析,发现测量信号具有直流分量,且在100~600 Hz频段具有较高的能量。在不同的气流量和固体流量下进行实验,通过设计的直流滤波电路,对比研究测量信号直流分量幅值及100~1000 Hz频段交流分量幅值与颗粒速度,浓度的关系,发现信号直流分量幅值与颗粒浓度之间具有更好的正相关关系。

In gas-solid two-phase flowmeasurement based on electrostatic method with embedded ring electrode, themeasured signal contains not only the information of electrostatic inducedcharge, but also the information of charge transferred by collision betweencharged particles and tube wall. Because the fluctuation amplitude of thesignal generated by electrostatic induction is equal, the mean value in timedomain is 0. When the pipe material is stainless steel, the total transferredcharge from contact of particles and the pipe wall is positive, and the averagevalue in time domain is positive. Through the analysis of the output signal ofthe measurement circuit, it is found that the measurement signal has DCcomponent and high energy in the frequency band of 100~600 Hz. Experiments werecarried out under different gas and solid flow rates. Through the designed DCfilter circuit, the relationship between the amplitude of DC component and theamplitude of AC component in 100~1000 Hz frequency band and particle velocityand concentration was compared and studied. It was found that there was a betterpositive correlation relationship between the amplitude of DC component andparticle concentration.