Bubble Temperatures Research Articles

Bubble-Temperature Measurements on Some Binary Mixtures Formed by Tetrahydrofuran or Amyl Alcohol with Hydrocarbons, Chlorohydrocarbons, or Butanols at (94.6 or 95.8) kPa

Bubble temperatures at 94.6 kPa for the binary mixtures formed by tetrahydrofuran with n-heptane, cyclohexane, methylethyl ketone, and amyl alcohol with 1,2-dichloroethane, 1,1,1-trichloroethane, and 1,1,2,2-tetrachloroethane, and 95.8 kPa for the binary mixtures formed by tetrahydrofuran with 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, trichloroethylene, tetrachloroethylene, and n-, iso-, sec-, and tert- butanols were measured over the entire composition range. A Swietoslawski-type ebulliometer is used for the experiments, and the Wilson model is found to represent the data well.

Bubble Temperatures of the Binary Mixtures of Dimethylcarbonate with Some Alcohols at 95.8 kPa

Boiling temperatures at 95.8 kPa over the entire composition range are measured for the binary systems formed by dimethylcarbonate with ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, and tert-butanol. A Swietoslawski-type ebulliometer was used for the measurements. The composition vs temperature measurements are well represented by the Wilson model.

Bubble Temperature Measurements on Binary Mixtures Formed by Cyclohexane at 94.7 kPa,

Bubble temperatures at 94.7 k Pa, over the entire composition range, are measured for eight binary mixtures formed by cyclohexane with 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, epichlorohydrin, 1,2-dimethoxyethane, 1,4-dioxane, 2-picoline, N,N-dimethylformamide, and dimethylacetamide. A Swietoslawski-type ebulliometer was used for the measurements. The liquid-phase mole fraction versus temperature measurements were represented by the Wilson model.

BUBBLE TEMPERATURES OF THE BINARY MIXTURES OF 1,2-DIMETHYLBENZENE WITH 2-PROPANOL, 1-BUTANOL, 2-BUTANOL, 2-METHYLPROPAN-1-OL AND 2-METHYLPROPAN-2-OL AT 95 kPa

Bubble temperatures at 95 kPa over the entire composition range are measured for the five binary systems formed by 1,2-dimethylbenzene with 2-propanol, 1-butanol, 2-butanol, 2- methylpropan-1-ol, and 2-methylpropan- 2-ol. A Swietoslawski - type ebulliometer was used for the measurements. The composition versus temperature measurements are well represented by the Wilson model.

Water vapor diffusion effects on gas dynamics in a sonoluminescing bubble.

Calculations based on a consideration of gas diffusion of gas dynamics in a sonoluminescing bubble filled with a noble gas and water vapor are carried out. Xenon-, argon-, and helium-filled bubbles are studied. In the absence of shock waves, bubble temperatures are found to be decreased, a decrease attributable to the large heat capacity of water vapor. Peak bubble temperature reductions are seen in bubbles containing Xe or Ar but not in those containing He. Further extrapolations provide evidence for the occurrence of shock waves in bubbles with Xe and water vapor. No shock waves are observed in bubbles with Ar or He.

Bubble Temperature Measurements on Binary Mixtures Formed by Cyclohexane at 94.7 kPa

Bubble temperatures at 94.7 k Pa, over the entire composition range, are measured for eight binary mixtures formed by cyclohexane with 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, epichlorohydrin, 1,2-dimethoxyethane, 1,4-dioxane, 2-picoline, N,N-dimethylformamide, and dimethylacetamide. A Swietoslawski-type ebulliometer was used for the measurements. The liquid-phase mole fraction versus temperature measurements were represented by the Wilson model.

The cavitation induced Becquerel effect and the hot spot theory of sonoluminescence

Over 150 years ago, Becquerel discovered the ultraviolet illumination of one of a pair of identical electrodes in liquid water produced an electric current, the phenomenon called the Becquerel effect. Recently, a similar effect was observed if the water surrounding one electrode is made to cavitate by focused acoustic radiation, which by similarity is referred to as the cavitation induced Becquerel effect. The current in the cavitation induced Becquerel effect was found to be semi-logarithmic with the standard electrode potential that is consistent with the oxidation of the electrode surface by the photo-decomposition theory of photoelectrochemistry. But oxidation of the electrode surface usually requires high temperatures, say as in cavitation. Absent high bubble temperatures, cavitation may produce vacuum ultraviolet (VUV) light that excites water molecules in the electrode film to higher H 2 O ∗ energy states, the excited states oxidizing the electrode surface by chemical reaction. Solutions of the Rayleigh–Plesset equation during bubble collapse that include the condensation of water vapor show any increase in temperature or pressure of the water vapor by compression heating is compensated by the condensation of vapor to the bubble wall, the bubbles collapsing almost isothermally. Hence, the cavitation induced Becquerel effect is likely caused by cavitation induced VUV light at ambient temperature.

Bubble temperature measurements on methanol with o-xylene and ethanol with m-xylene and p-xylene

Bubble temperatures at 95 kPa at seven liquid compositions, spaced evenly over the entire composition range, are measured for the three binary systems noted in the title, using a Swietoslawski-type ebulliometer. The temperature ( T) vs. composition ( x) measurements are found to be well-represented by the Wilson model. The calculated values of the vapor phase composition and the liquid phase activity coefficients are also presented.

Bubble-Temperature Measurements on p-Xylene with Methanol, Propan-1-ol, and Butan-1-ol at 95.1 kPa

Bubble temperatures at 95.1 kPa at nine liquid compositions, spaced evenly over the entire composition range, were measured for three binary systemsmethanol (1) + p-xylene (2), propan-1-ol (1) + p-xylene (2), and butan-1-ol (1) + p-xylene (2)using a Swietoslawski-type ebulliometer. The composition (x1) vs temperature (T) data were found to be well-represented by the Wilson model.

Statistical mechanics of bubbly liquids

The dynamics of bubbles at high Reynolds numbers is studied from the viewpoint of statistical mechanics. Individual bubbles are treated as dipoles in potential flow. A virtual mass matrix of the system of bubbles is introduced, which depends on the instantaneous positions of the bubbles, and is used to calculate the energy of the bubbly flow as a quadratic form of the bubbles’ velocities. The energy is shown to be the system’s Hamiltonian and is used to construct a canonical ensemble partition function, which explicitly includes the total impulse of the suspension along with its energy. The Hamiltonian is decomposed into an effective potential due to the bubbles’ collective motion and a kinetic term due to the random motion about the mean. An effective bubble temperature—a measure of the relative importance of the bubbles’ relative to collective motion—is derived with the help of the impulse-dependent partition function. Two effective potentials are shown to operate: one due to the mean motion of the bubbles, dominates at low bubble temperatures, where it leads to their grouping in flat clusters normal to the direction of the collective motion, while the other, temperature-invariant, is due to the bubbles’ position-dependent virtual mass and results in their mutual repulsion. Numerical evidence is presented for the existence of the effective potentials, the condensed and dispersed phases, and a phase transition.

Bubble Temperature Measurements on 2-Propyn-1-ol with 1,2-Dichloroethane, 1,1,1-Trichloroethane, and 1,1,2,2-Tetrachloroethane

Bubble temperatures at 26.6, 66.5, and 93.8 kPa at ten liquid phase compositions spread evenly over the entire composition range are measured for the three binary systems noted in the title, using a Swietoslawski type ebulliometer. The temperature (T)-composition (x) data are found to be well represented by the Wilson model. The calculated values of the vapor phase composition and the liquid phase activity coefficients are also presented.

A comparison of two-phase and well-mixed models for fluidized-bed polyethylene reactors

A steady-state model incorporating interactions between separate bubble and emulsion phases in a fluidized-bed polyethylene reactor was developed by Choi and Ray [ Chem. Engng Sci. 40, 2261–2279 (1985a)]. Correlations for maximum stable bubble size indicate that bubbles within the bed are considerably smaller than those in their original model. In the paper, the influence of bubble size and superficial velocity on reactor operation are examined. It is shown that bubble size critically influences the rate of heat and mass transfer within the bed, and when the bubbles are as small as those predicted by the maximum stable bubble size correlations, there is little or no resistance to the transfer of monomer and heat between the phases. A simplified well-mixed model is developed to describe reactor operation in the limiting case where there is no difference between bubble and emulsion gas temperatures and concentrations. The differences between the predictions of temperature and monomer concentrations of the two-phase and simplified models are less than 2 or 3 K and 2 mol%, respectively, in the operating range of industrial interest. Therefore, a simple back-mixed model is appropriate for predicting temperature and concentration in the gas phase of industrial fluidized-bed polyethylene reactors.

Empirical method for selecting working pairs for sorption heat pumps and for estimating isobaric bubble temperatures

By the use of the integral enthalpy of evaporation of binary mixtures obtained from the linearized Clapeyron diagram (In P against 1/T plot) an expression was derived which may be useful for screening purposes when new working pairs are to be selected. For the construction of the Clapeyron diagram, the knowledge of isobaric bubble temperatures of binary mixtures is required. Suitable mixtures for heat pumping consist of polar components and exhibit normally strong negative deviations from Raoult's law. A method for the estimation of isobaric bubble temperatures of binary organic and organic/water mixtures was derived and tested. The method was based on an empirical generalization of Clapeyron's and Raoult's law for dilute solutions, certain symmetry properties of the linearized Clapeyron diagram and the knowledge of pure component properties. For 35 test mixtures, a total average deviation of 1·42% of estimated thermodynamic bubble temperatures was calculated.

A measurement of vapor-liquid equilibria at extreme dilution.

Vapor-liquid equilibrium (VLE) data for a mixture at extreme dilution in the range 10-2 to 10-5 mole fraction are necessary in a high-grade purification by distillation. However, it is difficult to measure the VLE data in such a dilute concentration range by the conventional methods. This paper presents a method for measuring the VLE data at extreme dilution using the ebulliometer, by which bubble temperatures of the mixture of charged composition can be accurately measured by taking account of the vapor-phase holdup. This method has been applied to measurement of VLE data for four binary systems of water with alcohols as dilute solutes at 101.325 kPa.

Calculation of pH and mineral equilibria in hydrothermal waters with application to geothermometry and studies of boiling and dilution

Using chemical analyses and 25° pH measurements of quenched high-temperature waters, we calculate in situ pH and distribution of aqueous species at high temperature. This is accomplished by solving simultaneous mass action equations for complexes and redox equilibria and mass balance equations, on all components, including a H + equation with as many as 60 terms (depending on water composition). This calculation provides accurate values for the activities of aqueous ions in a given water at high temperature, which are used to calculate an ion activity product ( Q) for each of more than 100 minerals. The value of log( Q/ K) for each mineral, where K is the equilibrium constant, provides a measure of proximity of the aqueous solution to equilibrium with the mineral. By plotting log Q/ K vs. T for natural waters, it is possible to determine: a) whether the water was in equilibrium with a host rock mineral assemblage, b) probable minerals in the equilibrium assemblage and c) the temperature of equilibrium. In cases where the fluid departs from equilibrium with a host rock assemblage, it is possible to determine whether this may result from boiling or dilution, and an estimate of amount of lost gas or diluting water can be determined. The calculation is illustrated by application to geothermal waters from Iceland, Broadlands, and Sulphur Bank, hot spring waters from Jemez, Yellowstone and Blackfoot Reservoir (Idaho) and fluid inclusions from the Sunnyside Mine, Colorado. It is shown that most geothermal waters approach equilibrium with a subsurface mineral assemblage at a temperature close to measured temperatures and that some hot springs also approach equilibrium with the host rock at temperatures above outlet temperatures but commonly below the Na-K-Ca temperatures. The log Q/ K plots show that some discrepancies between Na-K-Ca temperatures on spring waters and actual temperatures result from a failure of alkali feldspars to equilibrate with the fluid and with each other. Calculations on Sulphur Bank fluids show that boiling probably caused cinnabar precipitation near 150°C and that the boiled fluids equilibrated with secondary minerals near 150° even though temperatures up to 185° have been measured at depth. For the fluid inclusions, the measured bubble temperatures are close to those calculated for equilibration of the fluid with the observed sulfide mineral assemblage. New estimates of stability constants for aluminum hydroxide complexes are included at the end of the paper.

Biaxial stretching of heat‐softened plastic sheets: Experiments and results

AbstractA second‐generation apparatus was built and used to inflate heat‐softened plastic sheets to shapes from hemispheres to large spheroidal bubbles. Three sheet materials, polystyrene, high‐impact polystyrene, and cellulose acetate butyrate, were successfully formed beyond the hemispherical shape at temperatures somewhat below industrial levels. Four others, rigid poly‐(vinyl chloride), an acrylic‐modified PVC, cast poly(methyl methacrylate), and polycarbonate, could not be deformed beyond the hemispherical shape without rupture. Measurements included bubble profiles, thickness distributions and local extension ratios for the final bubbles; two plots of profile growth measured from high‐speed motion pictures; and a continuous record of bubble temperatures and blowing pressure from which the meridional temperature distributions were plotted.Fifteen bubbles were measured and analyzed. Profiles and extension ratios were compared with those computed from the equations of isotropic, isothermal elasticity, using several different strain‐energy functions with constant material parameters. Agreement over all fifteen bubbles on all properties was about ±10.8 percent (absolute) for the best models considered. Bubble growth occurred over periods of 5 to 8 seconds, with about 90 percent of the final area of the larger bubbles being generated in the final 1.5 seconds. The maximum areal elongations obtained were 18,600 percent for clear polystyrene at 238°F, 14,300 percent for high‐impact polystyrene at 224°F, and 1,010 percent for cellulose acetate butyrate at 280°F.

MEASUREMENT OF VAPOR-LIQUID EQUILIBRIA BY DEW-BUBBLE POINT METHOD AND BUBBLE-CONDENSATION POINT METHOD

Vapor-liquid equilibrium relationships of four binary systems containing dioxane were measured at atmospheric pressure without using any analytical instrument. The dew-bubble point method was used for the systems methanol-dioxane and ethanol-dioxane. For other systems, benzene-dioxane and ethyl acetates-dioxane, the bubble-condensation point method was applied in the present investigation. The experimental dew, bubble and condensation point temperatures were measured by using a flow-type apparatus. As a result, a minimum azeotrope was observed in the ethanol-dioxane system. The other three binary systems measured were nonazeotropic.

Transfer of heat from bubbles in a fluidised bed

Experimental measurements of heat transfer from a gas-fluidised bed to a chain of gas bubbles are presented. Glass beads were fluidised in a vertical cylinder at the minimum velocity by heated air while a cold air stream was introduced at the center of the base plate from a single orifice. Steady-state dense-phase and bubble temperatures were measured with bare thermocouples immersed in the bed. The data were analysed with a bubble and dense-phase energy balance assuming equilibrium between gas and solids in the dense phase. Heat transfer coefficients for bubbles are presented versus flow rate with particle size as a parameter. The concept of a bubble model for heat transfer is compared to the classical plug flow model by which all previous data were analysed. The notion that bubble to dense-bed heat-transfer resistance is limiting while local equilibrium occurs in the dense bed is consistent with heat transfer observations and bubble fluid mechanics using no adjustable parameters.