Quality check of wire-mesh sensor measurements in a vertical air/water flow

Abstract

Extensive measurements were executed for a vertical upward air/water flow to generate a high-quality database for the development and validation of CFD-Codes for two-phase flows (e.g. for models on bubble forces or on coalescence and break-up). Thereto, in a pipe with a nominal diameter of 200 mm, the wire-mesh sensor technology was used. The present paper aims on the assessment of uncertainty caused by the experimental procedure and especially global deviations arising from the use of the wire-mesh sensor technology. Special attention was paid to the plausibility and accuracy of the data regarding the evolution of the vertical multiphase flow. In the result, a clear and consistent trend regarding their evolution with increasing distance from the position of the gas injection was found. Comparisons of the trend of time and cross-section averaged gas volume fraction along the pipe height with the theoretically expected values were carried out. From the measured radial profiles of the void fraction and the velocity of the gas phase, the superficial gas velocity at the wire-mesh sensor is integrated over the cross-section and compared with the set value from the test matrix. Thus, a general uncertainty analysis of the sensor data is possible.