Pressure fluctuations and flow pattern recognition in vertical two phase gas-liquid flows

Abstract

Presented are measurements of wall pressure fluctuations and pressure drop fluctuations for the flow regimes of bubbly, slug, churn, and annular type. Schematic of the air water loop that was used for the measurements is shown. Two phase gas-liquid flows play an important role in advanced energy conversion systems, large industrial chemical reactors, and diverse systems such as oil gas pipelines and nuclear reactors. Flow pattern maps based on visual observations have been developed by various investigations and form the basis for predicting flow regimes. The probability density function (PDF) of the pressure drop signal can be used objectively to discriminate between the various flow regimes in vertical two phase gas-liquid flows when the average pressure drop is mostly gravitational. This technique of flow pattern recognition, unlike the x-ray technique, is simple and applicable to large sized ducts without increase in cost or complexity.