Bias errors induced by cross-talk in two-phase flow measurements

Abstract

Cross-talk was identified as an important elemental uncertainty source in dispersed two-phase flow measurement with laser-Doppler anemometry or particle tracking velocimetry. Analytical formulations are presented to quantify the cross-talk bias errors introduced to the ensemble-averaged mean and root-mean-square (rms) velocities. Experimental data available in the literature were used to demonstrate the possible unintended consequences of these errors. It was found that these cross-talk errors are closely related to the slip velocity between the two phases. The error in the mean velocity is proportional to the cross-talk ratio times the slip velocity. The error in the rms velocity depends on the rms velocities of each phase, the cross-talk ratio, and the slip velocity. In practice, the presence of cross-talk may lead to either under- or overestimation of the true velocities.