Statistical properties of differential pressure fluctuations and flow patterns in horizontal gas-liquid two-phase flow (Differential pressure between the top and the bottom of a tube cross-section)

Differential pressure fluctuations are used to measure flow patterns of horizontal two-phase flow because the fluctuations seem to be closely connected with the flow structure. The differential pressure is used to eliminate the effect of pressure fluctuations occurring outside the test section and is measured at the interval between the top and the bottom at a cross-section of a tube to detect a local and instantaneous flow change. Results show that the horizontal flow of nitrogen gas (or air)-water mixture exhibits peculiar features of statistical properties such as the probability density function, the power spectral density and the cross-correlation, and its flow patterns can be classified by using the features.