Steady motion of a gas bubble in a liquid

A method is proposed for calculating the velocity of a gas bubble during a steady lift in a liquid, on the assumption that the bubble transmits to the medium an array of weak waves.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 25, No. 4, pp. 656–662, October, 1973.     

Model of gas bubble breakup in a turbulent liquid flow

A system of equations for evolution of the size spectrum of gas bubbles as a results of their breakup in an isotropic turbulent damped flow of an incompressible liquid is derived and solved numerically.Academic Scientific Complex A. V. Luikov Heat and Mass Transfer Institute, Academy of Sciences of Belarus, Minsk, Belarus. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 68, No. 2, pp. 192–204, March–April, 1995.     

Growth of a bubble of noncondensing gas injected into a liquid

The solution of the problem of growth of a gas-vapor bubble injected into a liquid is obtained. The growth of the bubble depends on mass transfer in the gas phase and heat transfer in the liquid phase. Experimental and theoretical data are compared.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 32, No. 6, pp. 978–989, June, 1977.     

Dynamics of a gas bubble rising through a thin immersed layer of granular material: an experimental study

 Packings of non-cohesive grains, immersed in a fluid, differ significantly from classical porous media as the grains, subjected to stresses and flows, can move within the sample, changing then the local properties of the material. We study experimentally the conditions for a gas to pass through a layer of immersed granular material. Above a threshold pressure, which depends mainly on the grains size and on the surface free energy of the liquid-gas interface, the gas creates a channel within the whole thickness of the layer. Received: 23 January 2002     

Study of the discharge process into a liquid of a gas stream from an immersed nozzle

The results of an experimental investigation of the discharge into a liquid of a gas stream from an immersed nozzle, positioned at an arbitrary angle to the surface, are presented. It is assumed that the gas is not dissolved in the liquid, i.e., it is nonassimilable.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 33, No. 2, pp. 213–223, August, 1977.     

Dynamics of the formation of bubbles in a vibrating capillary

The instant of separation of a gas bubble from a liquid occupying a vibrating capillary at Reynolds numbers of Re < 100 is considered. The dimensions of the bubble are determined analytically in relation to the amplitude and frequency of vibration of the capillary. The results are compared with experiment. Three basic conditions of bubble formation are distinguished.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 25, No. 3, pp. 424–429, September, 1973.     

Mechanism of gas bubble shoot-off and motion during spark discharge in liquid

The conditions of the excitation of a pulsed plasma discharge on the surface of a processed metal (copper) sample immersed in a conducting aqueous solution have been studied. Cathode polarization of the metal was provided by a high-voltage capacitor bank (4??F) charged to U = 200?C1100 V after each discharge. It is established that electric breakdown with a duration not exceeding 0.1 ??s is always preceded by the formation of small hydrogen bubbles (with radii r ?? 37?C40 ??m) on the polarized metal surface, which takes about 139?C159 ??s. A mechanism of passivation of the processed metal surface by these hydrogen bubbles, which are synchronously shot off from the electrode surface under the action of the spark discharge, is proposed. Consistent matching of the experimental data and model calculations is used to estimate the main parameters determining the kinetics of bubble detachment from the electrode surface at various voltages U on the capacitor bank.     

Flow of a stream of unevenly heated liquid over a gas bubble at low marangoni numbers

The problem of the thermocapillary convection in an unevenly heated liquid near a gas bubble is solved analytically. Estimates are given for the velocity of drift and the shape of the bubble and the vortex boundary.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 32, No. 2, pp. 251–256, February, 1977.     

Detonation waves in a multicomponent bubble liquid

The features of evolution of detonation waves in bubble liquid containing bubbles, some of which consist of combustible gas mixture and others of which contain inert gas, have been considered. The dynamics of inert bubbles against the background of a detonation wave appearing because of bubbles of the combustible gas mixture has been studied.     

Cavitation bubble dynamics in a polar liquid

It is suggested to introduce a new term into the equation describing the cavitation bubble dynamics in a polar liquid that takes into account a finite relaxation rate of dipole molecules of the liquid during rapid collapse of the bubble. It is shown that solutions of the modified equation provide significantly lower values of the thermodynamic parameters of the gas at the end of the collapse, so that thermal mechanisms of the high-energy processes accompanying cavitation cannot be operative. A substantial difference between commonly accepted notions and the proposed physical mechanism of accumulation of the acoustic field energy is demonstrated, whereby the energy is concentrated in the electrostatic field of oriented dipoles rather than in the form of the energy of compressed gas in the cavitation bubble. Experimental data are presented that confirm the proposed model.     

Influence of gas compressibility on the critical conditions for instability in the electrostatic field of a bubble in a dielectric liquid

It is shown that unlike the case of a liquid droplet, the critical strength of a uniform electrostatic field required for instability of a gas bubble in a liquid dielectric decreases as the compressibility of the gas in the bubble increases. Pis’ma Zh. Tekh. Fiz. 24, 49–54 (November 12, 1998)     

Rayleigh equation for the growth of a gas bubble under conditions of finite liquid volume

An equation is presented for the growth of a stationary spherical gas bubble in a finite spherical liquid volume, for which the familiar Rayleigh equation is the zero-order approximation. The results of computer solutions of the derived equation and the Rayleigh equation are compared.     

Realization of high pressures and temperatures in the gas phase of a bubble liquid flowing through a nozzle

A steady flow of a bubble gas-liquid mixture in a nozzle having a circular cross section has been investigated. The possibility of realization of superhigh temperatures and pressures in the gas phase of the mixture in the region near the smallest cross section of the nozzle has been analyzed. The influence of the initial radius of the flow and the volume content of bubbles, determining the volumetric rate of flow of the liquid supplied to the nozzle, on the pattern of the flow has been considered. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 6, pp. 134–137, November–December, 2007.     

Local gas content and velocity of the liquid phase in ascending bubble flow

The results of an experimental investigation of the characteristics of ascending gas-liquid flow in a pipe for gas bubbles of different diameters are given.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 52, No. 2, pp. 181–186, February, 1987.     

Heat transfer on a flat plate immersed in a laminar flow of a heated liquid

The case of one-sided heat transfer to a flat plate immersed in a flow of heated liquid is examined. Equations are obtained for the liquid temperature distribution in the boundary layer, and for the heat flux from the liquid to the wall.     

Generation of shear waves in gas by a vibrating surface

The problem on generation of shear waves in gas by a vibrating surface is considered in view of the properties of the surface. The problem is solved by two methods, namely, by analytic method using hydrodynamic equations and by the moments method using kinetic equation. Comparison of the respective results is made.     

液体中包膜气泡的非线性振动特性

1引言 液体中气泡振动学是一个具有理论及实用意义的课题,以往已有很多研究,并取得了相当的进展[1-4].一般自由气泡在液体中容易溶解,而如在气泡外附加一粘弹材料表面层则可使气泡在液体中的稳定性大大提高.因此包膜气泡更具有实用价值,已作为超声造影剂获得重要应用.包膜气泡的应用研究已涉及气泡的线性散射,非线性二次谐波成像.近年来更出现次谐波成像的研究,Church推导了包膜气泡模型并给出了弱非线性情况下的逐级近似解[5].但是至今尚无用动力学方法分析包膜气泡非线性特性的相关工作.     

Influence of wettability on bubble formation in liquid

This paper presents experimental results of the surface phenomena effect on bubble formation from a single orifice in water and at nozzle in liquid aluminium with gas blowing at small flow rates. The usage of coated orifice in water and nozzles of different materials in the melt realized wide range of contact angles. The meaningful stages, termed (1) nucleation period, (2) under critical growth, (3) critical growth and (4) necking, were identified during bubble formation in a regime referring to simultaneous forced flow and surface tension control. It was revealed that bubble formation is substantially dominated by hysteresis of contact angle. Evolution of interface equilibrium and force balance conditions distinctive for bubble formation is clarified. X-ray fluoroscope was used to carry out in-situ observation of bubble formation in the melt. It was shown that bubble volume increased with wettability worsening both for aqueous and metallic systems. A further insight into the mechanism of the bubble formation was obtained by comparison of the bubble behaviour at the tip of the injection devices in liquid aluminium and at the orifice in water.