中文摘要：

利用双截面ERT系统测量气液两相流流速具有高实时性、非侵入测量等优势,并将流速测量问题转化为信号处理中的时延估计问题。由于气液两相流信号大多是非平稳的,因此利用传统互相方法计算时延会出现相关函数曲线多峰值现象,导致流速计算结果严重偏差。为提高流速测量的精度和稳定性,本文出了一种基于提升小波的时延估计算法。该算法基于基小波二次加权理论,利用改进阈值函数提升小波算法对源信号进行去噪,再通过形态学提升小波对互相关计算结果去噪,实现流速精确测量。

英文摘要：

By adopting two-section ERT system, the Gas-liquid two phase velocity measurement is tramsformed into time delay estimation,due to the ERT has the advantages of high real-time and non-intrusive measuring. The Gas-liquid two-phase flow signals are mostly non-stationary,hence,cross correlation analysis with traditional time delay algorithms will bring multi-modal function which leeds to a serious deviation of two-phase velocity measurement. Aiming to improve measuring accurancy and stability,a novel time delay estimationalgorithm is proposed with the lifting wavelet. Based on re-weighting method with mother wavelets,the improved threshold lifting wavelet function removes the noise of the raw signal,and the Morphological Lifting Wavelet is utilized to denoise the lagging correlation between the upstream and downstream for time delay estimation to obtain the accurate velocity result.