HHT在多相流差压信号消噪上的应用

Application of HHT to denoise the multiphase flow differential pressure

为有效提取噪声背景下的多相流差压信号,提高流量的测量精度,针对实际差压信号非线性非平稳的特点,提出基于Hilbert-Huang transform(HHT)的多相流差压信号消噪方法.该方法利用经验模态分解(EMD)把差压信号分解成有限个固有模态函数(IMF),然后分析各个固有模态函数的边际谱,利用HHT不同频段能量分布的差异除去噪声,从而得到有用差压信号.将该方法应用于现场采集的差压信号,结果表明,HHT在处理非线性非平稳信号上具有良好的效果,可以有效去除高频噪声,得到的差压波动信号能很好地保持信号的局部特性,并最终提高多相流量计的测量精度.

In order to get rid of noise component from differential pressure signal of multiphase flow and improving the accuracy of flow measurement,a denoise method is proposed,which is based on Hilbert-Huang transform（HHT） because of the nonlinear and nonstationary property of multiphase flow differential pressure.The differential pressure signal is decomposed into a finite number of intrinsic mode function（IMF） by the empirical mode decomposition（EMD）.Then the marginal spectrum of every intrinsic mode function is analyzed.The difference of energy distribution among every frequency range is adopted to remove noise.The practical differential pressure signal of multiphase flow is denoised by the method.The results show that HHT demonstrates good results in dealing with nonlinear and nonstationary signals.It can effectively remove high frequency noise and preserve local characteristic,which finally improve the measure accuracy.