Assessment of the performance of an air-water probe on a calibration bench for two-phase flow measurement equipment

Despite significant advances in the study of two-phase water-air flows, there are doubts about the accuracy of experimental campaigns, as equipment often tend to ignore the calibration phase. The limitations inherent in existing measurement techniques have driven the present research. The aim of this work is to deepen the understanding of the operation of a dual-tip optical fiber probe, tested on a calibration bench with a void fraction of 32.13%. To achieve this concentration, a water flow rate of Q(w) = 2.26 L/s and an air flow rate of Q(a) = 1.07 L/s were used. The evolution of the main variables has been analyzed in the transverse direction of the jet, considering cross-sections located at different distances from the nozzle outlet. These variables include void fraction, phase change frequency, velocity, and Sauter mean bubble diameter.