Statistical Characeristics of Two - Phase Pressure Drops through an Orifice for Horizontal Condensing Flows

Experiments have been carried out to investigate the statistical characteristics of instantaneous pressure drops at a sharp-edged orifice for condensing flow with R-113. Tests were made for several two-phase flow regimes such as plug, slug, wavy and annualr flows. The probability density function (PDF), the power spectral density function (PSDF) and the autocorrelation function of the instantaneous pressure drop traces for the flow regimes were obtained. It was found that some distinctive features existed in the distribution of these functions, depending upon the two-phase flow pattern. Some statistical properties of the traces were also calculated such as the skewness coefficient and the kurtosis coefficient. These results indicate that the two-phase flow regime may be identified based on a statistical analysis of the instantaneous pressure drop trace at the orifices.