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A. J. An experimental technique is described for estimating the coalescence frequency of droplets in an agitated liquid-liquid system. Results are presented for dilute aqueous dispersions in toluene. Quantitative estimates of the coalescence frequency are based upon a simple model proposed to describe the coalescence process. The coalescence frequency is shown t o increase markedly with increase in impeller speed and to a lesser extent with increase in the dispersed-The studies reported here were con-~ Glenn L. Damerell is with €he Minnesota Mining and hlanufacturing Company, St. Paul, Minnesota. Vol. 8, No. 2

This paper presents the results of an experimental investigation in which boiling heat transfer data for Freon 1 1 and Freon 113 refrigerants were obtained. The experimental apparatus used for the investigation i s described. Forced convection boiling heat fluxes, heat transfer coefficients, and pressure drops were determined. The effects of mass flow rate, evaporation pressure, liquid film superheat, and exit vapor Reynolds number are presented. The coefficient CSF, appearing in Rohsenow's correlation for nucleate boiling, i s determined for both fluids in stainless steel and copper tubes. Two-phase flow pressure drops ore presented for both refrigerants as a function of mass flow rate and exit quality. l I ~ ~ ~ ~ Abstract: The mixing characteristics for combinations of plates ond downcomers for Glitsch V-1 ballast trays were determined with a three-plate column that was 27 in. in diameter. The mixing could be described by an eddy diffusion model. Far combinations of plates and downcomers, the eddy diffusivity was found to be a function of the mean-linear velocity of the liquid and independent of the physical properties of the liquid as well as the gas flow rate throughout the range of liquid and gas flow rates employed in the investigation. A variety of liquids were used and the Peclet numbers ranged from 4.4 to 27. Enthalpy values for hypothetical fluids from vapor-liquid equilibrium data, Welker, A c = concentration of dichromate = total solids area, sq. cm.ion, g. moles/cc.Abstract: Graphite oxidation studies have been carried out in oxygen and in air between 400" and 530°C. An analytical system capable of detecting product carbon dioxide and carbon monoxide at concentrations less than 10 parts/million was developed and used during the work. Kinetic results are compared with literature data obtained under similar conditions. The effect of bulk and surface properties of the graphite on oxidation rate and product distribution is considered. A reaction mechanism is proposed which reconciles much of the published data and the results reported herein.The roles of capillary wicking and surface deposits in the attainment of high pool boiling burnout heat fluxes, Costello, C. P., and W.

We explore the effect of an applied homogeneous magnetic field on the electrospraying characteristics of a ferrofluid in the cone-jet mode. A sulfolane-based ferrofluid mixed with the ionic liquid ethyl ammonium nitrate has been synthesized. These mixtures have negligible volatility under ambient conditions and remain stable under a very wide range of electrical conductivities $K$. Magnetized Taylor cones spray with the same current emission characteristics as their non-magnetized counterparts in the shared voltage and flow rate parameter space. However, the magnetized Taylor cones studied remained stable at voltages 23 % lower than the non-magnetized spray; they also access flow rates 30 % and 40 % lower in ferrofluids with $K=0.3$ and $0.01~\text{S}~\text{m}^{-1}$. In the lower voltage ranges available only to magnetized tips, unusually long stable cones are observed. The magnetic stabilization mechanism responsible for these two effects remains unclear. It is noteworthy that these strong effects arise even when the tip curvature of the strictly magnetized liquid is orders of magnitude smaller than that for the strictly electrified liquid.

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