Hydrodynamics of Microbubble Suspension Flow in Pipes

Abstract

Microbubbles exhibit excellent gas-dissolution abilities owing to their larger gas–liquid interfacial areas and longer residence times compared to conventional larger bubbles. Hence, it is expected that microbubbles should increase the efficiency of gas–liquid contact devices for various applications in chemical and biochemical processes. In most of these applications, it is necessary to understand the hydrodynamics, such as the rheology, pressure drop, and friction factor, associated with microbubble flow in devices. This study investigates the hydrodynamic characteristics of the flow of a microbubble suspension in a surfactant solution through a pipe. A mechanistic model has been developed to analyze the interfacial stress of microbubble suspension flow in a pipe by considering bubble formation, drag at the interface, and loss of energy due to wettability. A correlation between the intensity factor of interfacial stress and the friction factor based on energy loss due to wettability has been developed. The functional form of the correlation appears to predict the hydrodynamics satisfactorily for the flow of a microbubble suspension in a pipe. The present study might be helpful in further understanding multiphase flow for industrial applications.

A micro‐jet array for economic intensification of gas transfer in bioreactors

“…Gas–liquid surface tension is seen to be insensitive to SDS concentration in this range of SDS concentrations, changing by less than 2%, to find the dependency ofbut at the same time d b and k L a respond very strongly to the presence of the SDS, as seen in the plot. The literature consensus is that surfactants cause a reduction in k L . We hypothesize that this surprising result is mediated by hydrodynamic slip vs nonslip flow at ∼10 μm spatial scales on the bubble–liquid interface during bubble collisions, such that a <1% change in surface tension is sufficient to alter the slip/no‐slip condition during bubble collision and drastically change the bubble coalescence rate.…”

“…The literature consensus is that surfactants cause a reduction in k L . [17][18][19][48][49][50][51][52][53] We hypothesize that this surprising result is mediated by hydrodynamic slip vs nonslip flow at $10 μm spatial scales on the bubble-liquid interface during bubble collisions, such that a <1% change in surface tension is sufficient to alter the slip/no-slip condition during bubble collision and drastically change the bubble coalescence rate. Deeper analysis of this coalescence phenomenon is the focus of a forthcoming paper.…”

Dispersion characteristics of ionic microbubble suspension in continuous plant prototype developed for mineral beneficiation

“…The surface tension of the liquid was measured by tensiometer (Model K9-MK1, KRÜSS GmbH, Hamburg, Germany). It is well known that microbubble suspension is a time- independent non-Newtonian pseudo-plastic fluid and its rheology is described by Ostwald-De Waele model or Power law model [21] t…”

“…The wall shear stress and apparent shear rate can be calculated from the volumetric flow rate of microbubble suspension (Q) and pressure drop (DP) in the pipe according to the following relations [21] …”

“…The rheology of microbubble suspension has been studied by many authors. The microbubble suspension has found to behave as non-Newtonian [20,21]. In the past few years, a lot of attention has been given to the potential applications of the microbubbles for water treatment due to their capability to generate highly reactive free radicals [22].…”