Showing papers in "International Journal of Multiphase Flow in 1991"

TL;DR: In this article, a two-fluid model of multidimensional laminar bubbly two-phase flow is developed and used to analyze vertical pipe flows and a Galerkin finite element method is utilized to perform the numerical evaluations.

TL;DR: In this article, a model for the prediction of the local frictional pressure drop of two-phase flows during vaporization of R-12 in capillary tubes is presented, with a relative error of about 15%.

TL;DR: In this paper, the authors reported void fraction, pressure gradient and flow pattern data for gas-liquid flow at near-zero gravity through a 4 cm dia tube about 3 m long.

TL;DR: A theoretical model for particle deposition on vertical walls is proposed in this article, which shows that the particle deposition massflux depends on the dimensionless particle relaxion time t P +, a dimensionless group Ei representing Brownian motion and the dimensioness group Mi representing electrostatistical forces, as well as a new dimensionless gv/μ 3 and the tube Reynolds number.

TL;DR: In this article, a small cross-sectional area (19.05 × 3.18 mm) rectangular channel with both the short and long sides forming the base, resulting in aspect ratios of 6 and 16, respectively, was studied.

TL;DR: In this article, a simple predictive tool for analyzing the annular core flow of two immiscible liquids is presented, which puts under a common framework all possible flow situations of laminar-laminar, turbulent-turbulent or mixed flow regimes in the two phases involved for wide ranges of viscosity and density ratios.

TL;DR: In this paper, a 32 mm dia vertical pipe with various forms of liquid outlet, namely a porous wall, a tapered outlet, and a square-edged outlet, was used to investigate the effect of churn flow on the penetration rate.

TL;DR: In this paper, the authors derived a correlation for drop size in annular flow based on a mechanistic model and obtained the optimum values of four constants by a fit to measured data over a wide range of gas and liquid flow rates, physical properties and pipe diameter.

TL;DR: In this paper, the authors collected time records of local liquid film thickness, using parallel-wire conductance probes, in a new 50.8 mm i.d. pipe loop, and performed statistical analysis of these records to study the circumferential variation of time-averaged thickness, of RMS values and other quantities.

TL;DR: In this paper, a relatively simple model is proposed for predicting the above quantities, where terms representing fluxes due to turbulent diffusion and gravitational settling are used in the model and an additional parameter a is introduced and is considered to represent a combination of fluxes; i.e. the net upward flux of droplets responding to turbulence and the flux of liquid that gain high inertia upon atomization.

TL;DR: In this paper, the internal phase distribution of air-water bubbly flow in a 50.3 mm dia transparent pipeline has been experimentally investigated by using a double-sensor resistivity probe.

TL;DR: In this article, a turbulent eddy-based surface renewal theory for condensation and evaporation of saturated vapor onto or from its liquid is proposed, which accurately predicts experimental data for horizontal, concurrent condensation of steam on water.

TL;DR: In this paper, the Theofanous-Saito correlation was used for predicting the critical heat flux in deep beds of non-spherical coarsely-sized particulates, and a plausible, mechanistic, model of the pre-dryout transient, considering coolant depletion phenomena and flooding limitations, was developed to analytically demonstrate the CEL behavior.

TL;DR: In this paper, the thickness of a thin liquid film formed between a free surface and the apex of a bubble which is approaching at its terminal velocity is measured using bubbles of < 1 mm dia both in distilled water and alcoholic solutions.

TL;DR: In this article, the attenuation and propagation characteristics for small amplitude concentration waves in vertical bubbly and particulate flows were studied up to concentrations of 44.3 and 58%, respectively, in a 10 cm pipe.

TL;DR: In this article, an experiment of direct contact condensation of saturated steam on subcooled water sprays characterized by droplets of uniform size has been carried out with the aim of testing the influence of droplet diameter and velocity on the heat transfer rate, up to a pressure of 0.6 MPa.

TL;DR: In this paper, a brief review of the continuum theory for macroscopic descriptions and the kinetic theory for microscopic descriptions in solid/liquid two-phase flows is presented, i.e. the solid phase may be described by the Boltzmann equation and the liquid phase still being described by conservation laws in continuum theory.

TL;DR: In this article, the authors show that the multivaluedness is not an artifact of the approximations made in the model, as it is also predicted by the exactly solvable case of laminar flow in an inclined square duct.

TL;DR: In this paper, a ring source on the wall of a film removal unit is used to model vertical gas/liquid annular flow and the dispersion of droplets from the wall.

TL;DR: In this paper, a theoretical and experimental study has been conducted for liquid and gas entrainment to a small break hole from a stratified two-phase region, where theoretical correlations previously obtained for top, side and bottom entrainments were modified to express the relation between break flow rate, break quality and bulk water level so that they can be used easily for any break geometry.

TL;DR: A review of the literature on laser Doppler anemometry (LDA) techniques to discriminate liquid from bubble velocities reveals that the techniques are unsuitable for large bubbles at moderate void fractions as discussed by the authors.

TL;DR: In this paper, the authors present dynamic measurements of the response of negatively buoyant non-colloidal spheres to a step change in the applied shear rate and estimate the shear-induced effective diffusivity within the plane of shear and the hindered settling factor in sheared suspensions at concentrations between 20 and 50% by volume.

TL;DR: In this paper, the aeration of a liquid body advancing over a slow moving liquid layer in a pipe has been experimentally investigated with a conductance method, and it has been found that net gas entrainment only occurs when the relative velocity between the advancing front and the liquid layer is greater than a limiting value.

TL;DR: In this paper, an experimental study has been carried out in which water drops with diameters between 1 and 3 mm have been suspended on a thermocouple junction in a saturated steam environment within a vessel at pressures up to 9 bar abs.

TL;DR: In this paper, the authors investigated the phenomenon of gas pull-through for the condition of simultaneous discharge from two small orifices (6.35 mm i.d.) located on the side of a high-pressure reservoir containing a stratified air-water mixture.

TL;DR: In this article, an alternative to perturbation techniques or full numerical solution is developed for the free-surface problem associated with an advancing liquid-gas contact line, which makes use of a local-wedge approximation to obtain the free surface pressure variation, leads to a second-order ordinary differential equation for the meniscus shape.

TL;DR: In this paper, a two-phase variable geometry jet pump with a diffuser was tested with a view to assessing how well the included diffuser handles inlet flows with considerable non-uniformities of both velocity and density.

TL;DR: In this article, a description of a uniform two-phase dispersion in a potential flow is developed in terms of a macroscopic (averaged) potential and the average velocity of each phase using analogues to electromagnetic theory.

TL;DR: The origin of solitary waves on gas-liquid sheared layers is studied by comparing the behavior of the wave field at sufficiently low liquid Reynolds number, R L, where solitary waves are observed to form, to measurements at higher R L where no such waves do not occur.