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利用双截面电容层析成像技术,将多相流速测量转化为时延估计问题。为提高流速测量的可靠性和准确性,分析研究了各类时延估计算法及其特点,结合双截面ECT系统对粉煤灰气力输运过程进行实时监测。该过程气固两相流速范围大致是0~14m/s,灰气质量比一般为10/1~40/1;颗粒度大约在2m~2mm。分别采用基于高阶统计量和小波变换的时延估计算法计算内径125mm的水平管道中的固体流速,实验结果证明了该测速方法的有效性。由于两相流信号具有非高斯非平稳特性,基于小波变换的时延估计算法可得到更准确的结果,基于互双谱的时延估计算法得到的流速与其相差1m/s左右。
Using double-section capacitive tomography, the multiphase flow rate measurement is transformed into the problem of time delay estimation. In order to improve the reliability and accuracy of flow rate measurement, various delay estimation algorithms and their characteristics are analyzed and studied. The dual-section ECT system is used to monitor the pneumatic transportation process of fly ash in real time. The process gas-solid two-phase flow rate range is generally 0 ~ 14m / s, the mass ratio of the gas is generally 10/1 ~ 40/1; particle size of about 2m ~ 2mm. The time-delay estimation algorithm based on high-order statistics and wavelet transform was used to calculate the solid velocity in a horizontal pipe with an inner diameter of 125mm. The experimental results proved the effectiveness of the method. Due to the non-Gaussian non-stationary characteristics of the two-phase flow, the time-delay estimation algorithm based on wavelet transform can get more accurate results, and the time-delay estimation algorithm based on cross-bispectrum has a velocity difference of about 1m / s.