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ISSN Online: 2377-424X

ISBN Print: 0-85295-345-3

International Heat Transfer Conference 10
August, 14-18, 1994, Brighton, UK

STATISTICAL CHARACTERISTICS OF INSTANTANEOUS PRESSURE DROPS THROUGH ORIFICES FOR VARIOUS TWO-PHASE FLOW REGIMES

Get access (open in a dialog) DOI: 10.1615/IHTC10.5530
pages 211-215

Аннотация

Experiments have been carried out to investigate the statistical characteristics of instantaneous pressure drops at sharp-edged orifices for horizontal air-water flow and condensing flow with R-113. Tests were made for several two-phase flow regimes such as bubbly, plug, slug, and armualr flows. The probability density function (PDF) and the power spectral density function (PSDF) of the instantaneous pressure drop traces for the flow regimes were obtained. It was found that some distinctive features exist 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. For bubbly flows, the PDF shows a single-peak distribution and is very close to the Gaussian distribution. The PSDF of bubbly flows has also a single-peak distribution. The PDF distribution has asymmetric shape around the peak in plug flows while the width of the PDF distribution becomes larger, compared to that of bubbly flows. In case of slug flows, the PDF distribution has a wide-spread shape and very low density with double peak. The PSDF distribution of both plug flows and slug flows has a very similar to that of bubbly flows. The PDF distribution of annualr flows is very similar in shape to that of bubbly flow but the PSDF has a quite different distribution with multiple peaks. These results indicate that the two-phase flow regime may be identified based on a statistical analysis of the instantaneous pressure drop trace at orifices.