Pseudo turbulence in laminar and transitional regimes of an upward bubble flow in a pipe

Abstract

In a bubble flow, both inherent liquid turbulence and pseudo turbulence induced by the bubbles are present. Total two-phase turbulence of the flow is determined by the interaction of these two components. The experimental values of the average wall shear stress and its pulsations obtained by eight double electrodiffusional probes located uniformly in one section along the pipe perimeter are presented. The gas phase is represented by monodisperse bubble mixtures with average diameters of 1 and 2 mm and a volumetric gas content of up to 20%. To modify the bubble Reynolds numbers, two working solutions with different viscosities were used. The superficial liquid velocity did not exceed 1 m/s. Flow regimes with deviations from the Sato hypothesis on the additivity of pseudo turbulence and inherent liquid turbulence were detected. At transitional liquid Reynolds numbers and small bubble Reynolds numbers, total two-phase turbulence is determined by pseudo turbulence, and there is no the influence of inherent liquid turbulence.