Showing papers on "Marangoni effect published in 1974"
TL;DR: In this article, the instability and breakup of laminar liquid jets in gaseous surroundings are investigated for conditions under which a solute is transferring across the jet interface rendering the system susceptible to Marangoni convection.
Abstract: The instability and breakup of laminar liquid jets in gaseous surroundings is investigated for conditions under which a solute is transferring across the jet interface rendering the system susceptible to Marangoni convection. Linear hydrodynamic stability analysis reveals that solute transfer out of the jet is stabilizing (produces longer jets) while transfer into the jet is destabilizing and promotes breakup. Solute adsorption, including as a limiting case the presence of a spread surfactant monolayer, may strongly counteract the stabilizing or destabilizing effects of mass transfer but has only a negligible effect on jet stability in the absence of interphase mass transfer. Qualitative experimental results for water jets in air with acetone as the transferring solute corroborate both the stabilizing and destabilizing mass transfer effects predicted by the theory.
29 citations
TL;DR: In this article, the influence of surface tension gradient induced flow, the Marangoni effect, was examined in detail using a fine cantilevered wire with an attached bubble as a means of measuring force with and without temperature gradients.
Abstract: Experiments were conducted to examine in detail the influence of surface tension gradient induced flow, the Marangoni effect. One set of studies provided visual results that demonstrated the occurrence and magnitude of the Marangoni effect. Another portion of the work was directed to bubble force measurements. These studies used the deflection of a very fine cantilevered wire with an attached bubble as a means of measuring force with and without temperature gradients. The experimental force data were found to check existing theoretical predictions reasonably well except for the case where the test fluid had a sizeable vapor pressure. In this situation the thermophoretic force on the bubble was much higher than predicted. The excess force was due to an evaporation and condensation process resulting from vapor pressure differences around the bubble surface.
20 citations
TL;DR: In this paper, a linear stability analysis for two immiscible viscous, initially motionless fluids, confined between horizontal solid walls of constant concentrations and subjected to both the Rayleigh and the Marangoni driving mechanisms, is presented.
Abstract: An analytical study of the stability of horizontal two-fluid layers encountered by interphasial mass transfer is reported. A linear stability analysis for two immiscible viscous, initially motionless fluids, confined between horizontal solid walls of constant concentrations and subjected to both the Rayleigh and the Marangoni driving mechanisms, is presented. The effect of interfacial contamination is also involved. Stability criteria for the cases of transfer of acetone or acetic acid through benzenewater interface are presented. As for acetic acid, instability is predicted for either direction of transfer, showing the importance of the Rayleigh driving mechanism. It relaxes the discrepancy between experimental results and the theoretical result of the purely Marangoni effect model of Stemling and Scriven. Stability criteria are strongly dependent on the ratios of properties of fluids, the total depth, and also the depth ratio of layers and the presence of interfacial contaminant. This analysis is readily applicable to predicting the stability of two-fluid layers encountered by heat transfer.
11 citations
TL;DR: In this paper, the critical Marangoni number is defined as the value which makes the temperature gradient at the interface vanishes, i.e., it is the value that makes the interface be at a higher temperature than the adjacent liquid unless the liquid looses heat to the gas.
6 citations
TL;DR: In this article, an analytical and experimental study of thermally induced instability in horizontal two-fluid layers is reported, where linear stability analysis is applied to predict the stability criteria of benzene-water and water-carbon tetrachloride layers.
Abstract: An analytical and experimental study of thermally induced instability in horizontal two-fluid layers is reported. The earlier reported linear stability analysis is applied to predict the stability criteria of benzene-water and water-carbon tetrachloride layers. Calculations predict instability in benzene-water layers of whatever depth ratio of layers for heating from above or below, but only for heating from below in equi-depth water-carbon tetrachloride layers. Results of experimental measurements of the critical Rayleigh and Marangoni numbers in these two-fluid layers of various total depths, heated from below, confirm the consistency of the theory both in clean and contaminated systems.
6 citations
TL;DR: In this article, the authors investigated the initiation of natural convection at gas-liquid interfaces and found that the conditions at the onset of observable convection were the same, if surface waves, meniscus and surface temperature gradient effects were eliminated from the experiment, even though the Marangoni number was three orders of magnitude above its predicted critical value.
4 citations
TL;DR: B, Marangoni number e(T, -7f variables defined by equations (7)-(10), convective heat-transfer coefficient; thermal conductivity of liquid; Riot number [hd/K]; dimensionless heat generation parameter as defined by equation (1) and (2); time; temperature; perturbation temperature.
1 citations
01 Jan 1974
TL;DR: In this paper, the contributions of diffusion and Marangoni convection to mass transfer rates in the bulk liquid have been estimated for the evaporative purification of molten alumina.
Abstract: Contamination from containers is a major problem in preparing ultrapure refractory materials. Space with its zero gravity and its high vacuum offers an opportunity for containerless purification of these materials. The evaporation of impurities from a melt will involve many complex chemical equilibria. Thermodynamic calculations have been modified to describe these equilibria when impurities in the melt evaporate into vacuum. The contributions of diffusion and Marangoni convection to mass transfer rates in the bulk liquid have been estimated. Calculations for the evaporative purification of molten alumina are given.