提出了一种管内煤粉体积分数的超声波测量方法,设定中心频率为31kHZ的一体式超声波探针,基于声散射理论模型,利用数值模拟结果拟合出超声波衰减系数随煤粉体积分数的变化关系,并对某电厂煤粉输运管道进行了管内不同深度测点煤粉体积分数的在线测量实验,通过对超声波信号分析得到对应的衰减系数值,分析超声波信号与煤粉体积分数之间的关系,得到煤粉体积分数.结果表明:衰减系数与煤粉体积分数存在线性关系;实验段煤粉管道内煤粉体积分数基本在0.09%~0.14%浮动;所提方法可为管内煤粉体积分数的实时在线测量提供一种行之有效的手段.
An ultrasonic method including a one-piece ultrasonic probe with 31 kHz center frequency was proposed for measurement of pulverized-coal concentration in power plant pipelines. Based on the model of acoustic scattering theory, the relationship between ultrasonic attenuation coefficient and pulverized-coal concentration was fitted by numerical simulation. The method was applied to measure the pulverized-coal concentration in different depths of the conveying pipeline in a power plant. Corresponding acoustic attenu- ation values were acquired by analyzing the oneline measurements of ultrasonic signals, then the pulver- ized-coal concentration was obtained based on analysis of the relationship between the ultrasonic attenua- tion coefficients and the pulverized-coal concentration. Results show that there exists a linear relationship between the ultrasonic attenuation coefficient and the pulverized-coal concentration~ the volumetric concen- tration of pulverized coal in the test section of pipeline lies in 0. 09%-0. 14%. Therefore the proposed method may serve as a reference for online measurement of pulverized-coal concentration in power plant pipelines.