Coalescence of Drops in a Turbulent Gas Flow

Droplets in motion in a turbulent flow of gas in a pipe are subject to breakage and coagulation (coalescence). These processes occur simultaneously and as a result a dynamic balance is established between them, determined by some distribution of drops with average radius i av- 

Assume that drops with radius R i av will undergo breakage, whereas drops with R J av will coalesce. 

In a turbulent flow there are two chief mechanisms of drop coagulation [2], that of turbulent diffusion and that of inertia. The inertial mechanism is based on the assumption that turbulent pulsations do not completely entrain the drop. As a result, relative velocities attained by drops due to turbulent pulsations depend on their masses. The difference in the pulsation velocities of drops of various radii causes their approach and leads to an increase of collision probability. The mechanism of turbulent diffusion is based on an assumption of full entrainment of drops by turbulent pulsations with scales, playing the chief role in the mechanism of approach of drops. Since drops move chaotically under the action of turbulent pulsations, their motion is similar to the phenomenon of diffusion and can be characterized by a coefficient of turbulent diffusion. 

The distribution of drops over volumes n (t, P, V) at a point in space P and at a moment in time t, in approximation of pair interactions, valid for a low volume concentration of drops, is described by the following kinetic equation  

The rate of formation of drops with volume V due to breakage is given by  

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Separation processes of gas-liquid (gas-condensate) mixtures are considered in Section VI. The following processes are described formation of a liquid phase in a gas flow within a pipe coalescence of drops in a turbulent gas flow, condensation of liquid in throttles, heat-exchangers, and turboexpanders the phenomena related to surface tension efficiency of division of the gas-liquid mixtures in gas separators separation efficiency of gasseparators equipped with spray-catcher nozzles of various designs - louver, centrifugal, string, and mesh nozzles absorbtive extraction of moisture and heavy hydrocarbons from gas prevention of hydrate formation in natural gas. 

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