Flow separators contact angles

Solid particles are not readily wettable when air is entrapped because the contact angle widens. Hydroscopic (or water-miscible) materials such as glycerin, alcohol, and glycol penetrate the spaces occupied by air and displace it. During the dispersion process, the hydroscopic materials separate the agglomerates and coat the particles so that water can flow into and wet the particles. 

A study of immiscible liquid/liquid displacement on model systems, paraffin oil/aqueous surfactant solutions in glass capillary tubes led to the conclusion that flow and wetting properties cannot be treated separately. Even though there is a correlation between static and dynamic contact angles, the validity of this relation is restricted to relatively low surfactant concentrations. 

We will focus first on theoretical considerations. Let us consider the case of two solid particles immersed in a liquid that forms a contact angle 0 > 90° with their snrface. When these particles are brought into contact, the liqnid will spontaneously flow out from a narrow gap separating the particle surfaces. As a result, a cavity filled with vapor from the escaping liquid is formed. 

The mesh reactor is an alternative continuous-phase microcontactor, where the gas and liquid flow through separate channels separated by a thin membrane. To provide stable operation, the fluid interface is immobilized by well-defined openings obtained with a thin mesh [72]. Interfadal forces help to stabilize the fluid interface within the openings, while fluid layers are thin enough to facilitate mass transfer. The meniscus shape at the interface between the two phases defines the available area for mass transfer and is a function of contact angle, pore geometry, and pressure difference between phases. The open area of the micromesh contactor is about 20-25%, which leads to a gas-liquid interfacial area of 2000 well above the values obtained in traditional stirred tank reactors. This... 

Jets can be collided frontal, i.e. at a 180° angle [52]. Here, the energy input is maximal. The fluid can be virtually atomized in this way and has to be surrounded by a mixing chamber to be re-collected. In a Y-type flow configuration, a softer contact can be achieved [39,136]. The two jets simply merge to a third one. Under unfavorable conditions, however, a separated, bi-laminated fluid system is achieved. 

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