Mass transfer in drops under conditions that promote oscillation and internal circulation

Abstract

Single drops supported on hypodermic tubing have been studied i n a wind tunnel to determine the effect of drop oscillation on mass transfer. The systems studied for the case where internal resistance controls consisted of absorption of sulfur dioxide gas by drops of glycerine, propylene glycol, and ethylene glycol. The results may be expressed in terms of effective diffusivity.No significant effect was noted in glycerine, whereas the glycols gave effective diffusivity values two to eight times greater than theoretically calculated values of molecular diffusivities.Frequencies, amplitudes, and internal circulation velocities in the drops were studied by cinematography.The effect of oscillation on external mass transfer coefficients was studied by sublimation of naphthalene spheres in air. In the cases where the vibrational velocity was less than the stream velocity, no effect was noted; this is in agreement with heat transfer studies.A technique has been developed for studying the effect of internal circulation on effective diffusivity by the use of forced circulation through a drop suspended on hypodermic tubing.A pseudofilm thickness is determined as a function of circulation velocity and presents a means of predicting effective diffusivities for the systems studied. This technique has been demonstrated, giving results in fair agreement with the correlation of Garner and Lane.

Modeling the SO2‐slurry droplet reaction

“…Work by Constan and Calvert (1963) and by Kinzey (1988) indicate that internal circulation is not significant within slurry droplets. Initially, the sorbent particles are, therefore, viewed as being uniformly distributed throughout the droplet.…”

Influence of the Lime Slurry Droplet Spectrum on the Efficiency of Semi‐Dry Flue Gas Desulfurization

“…During the solution of water evaporation and sulfur dioxide absorption, the internal circulation inside the droplet caused by shear stress on its surface is neglected due to the much higher viscosity of water, which was also proved by Reinhart [25] or Cinatan and Calvert [26]. The desulfurization model combines heat and mass transfer for a single computational droplet with the overall two-phase flow of the flue gases and the water droplets.…”

Mass transfer and internal circulation in forming drops

“…In work specifically designed to investigate quantitatively the effects of internal circulation on mass transfer rates in liquid drops, Constantan and Calvert (1963) used a tip of two concentric tubes to create a drop with a con. trolled amount of internal circulation.…”

“…In the present paper, the internal circulation patterns for forming and separating liquid drops for inlet Reynolds numbers less than 50 have been studied and, from a fixed volume drop formed on a tip having a concentric tube arrangement for addition and withdrawal of fluid in the same fashion as that used by Constantan and Calvert (1963), mass transfer rates for inlet Reynolds numbers less than 50 were measured.…”