气液两相段塞流的PSD和PDF特征分析

在气液两相段塞流理论基础上,通过大量实验,利用LabVIEW平台进行数据采集和处理,并引进数字信号理论和统计学分析方法,得出了段塞流在不同时期、不同形态的概率密度函数(PDF)特征和功率谱密度函数(PSD)特征.段塞流的压力概率密度函数呈现单峰、双峰、多峰分布,尤以双峰分布最为普遍;段塞流的压差概率密度函数分布符合正态分布,呈现单峰分布;段塞流的功率谱在整个频率范围内随着频率增大而缓慢下降,频率范围内出现两个幅度比较明显的特征峰.利用PSD和PDF特征分析可以进行气液两相流的流型识别,为研究流型和管道系统设计提供帮助.

Analysis of the PSD and PDF characteristics of gas-liquid slug flow

In the gas-liquid pipeline transmission,slug flow is the most common flow regime,which brings a lot of trouble to normal running of the pipeline.The probability density function(PDF) and the power spectral density function(PSD) characteristics of the pressure and the pressure difference of the slug flow under different conditions are obtained by a lot of experiments and the statistical analysis of experimental results.The experimental results are collected and processed using LabVIEW platform.It is shown that,the pressure PDF of the slug flow may present single-peak,double-peak or multi-peak distribution,and the double-peak distribution is the most common;the pressure difference PDF of slug flow accords with normal distribution,that is,it presents single-peak distribution;The PSD of slug flow gradually reduces with the increase of frequency,and two obvious characteristic peaks appear in the frequency range.The PSD and PDF characteristics of gas-liquid slug flow can be used for the identification of the flow patterns of gas-liquid two-phase flow,which can guide effectively the design and running of the multiphase pipeline system.