Showing papers in "International Journal of Multiphase Flow in 1986"

TL;DR: In this article, a two-phase mixture theory is presented which describes the deflagration-to-detonation transition (DDT) in reactive granular materials, based on the continuum theory of mixtures formulated to include the compressibility of all phases and the compaction behavior of the granular material.

TL;DR: In this paper, the local instantaneous formulation of the interfacial area concentration is introduced, and time and spatial averaged area concentrations are derived, and the local ergodic theorem is obtained for stationary developed two-phase flow based on the two-fluid model.

TL;DR: In this paper, the authors explored the application of linear stability theory to explain the onset of slugging and showed that the inviscid Kelvin-Helmholtz theory correctly predicts stability of a stratified flow only for very large liquid viscosities.

TL;DR: The local instant formulation of mass, momentum and energy conservations of two-phase flow has been developed in this paper, where the source terms at the interface are defined in terms of the local instant interfacial area concentration.

TL;DR: In this article, new models for the transition from annular to intermittent flow and from dispersed bubble flow for two-phase gas-liquid flow in inclined pipes were suggested. But the results of the models compare favorably with experimental data.

TL;DR: In this paper, it is shown theoretically that it is possible to stablize the flow by increasing the back pressure of the separator or by employing a controlled choking at the pipe exit.

TL;DR: In this article, the influence of the mist-annular transition on the heat transfer mechanism during condensation is studied and a heat transfer correlation is suggested for the mist region and shown capable of good agreement with a data base of different fluids and tube orientations.

TL;DR: In this article, a two-fluid model is presented which accounts for the interrelation between these variables, and new correlations for interfacial friction and liquid fraction entrained are proposed using data compiled previously at AERE Harwell.

TL;DR: In this article, a semi-empirical turbulence model for turbulent liquid films undergoing heating or surface evaporation was presented. But it was found that it is impossible to obtain universal correlations for different fluids in terms of Reynolds and Prandtl numbers alone since the heat transfer data display strong dependence on the Kapitza number below Re = 10,000.

TL;DR: In this paper, a model was developed to predict the branch quality and mass flux through small breaks in a horizontal coolant pipe, where stratified flow exists, and experiments were performed with air-water flows through breaks simulated by pipe stubs of various diameters located at the bottom, the top or in the side of a horizontal pipe.

TL;DR: In this paper, phase separation was measured in air-water and steam-water mixtures flowing through a T- junction with equal pipe diameters (d = 50 mm ) and a horizontal, vertical upward or vertical downward branch.

TL;DR: In this article, the dynamic structure and physical properties of magnetorheological suspensions are described in terms of a stationary model, according to which a suspension in a magnetic field represents a system of ordered noninteracting ellipsoidal aggregates oriented at some angle to the field.

TL;DR: In this article, the structure of dilute bubbly turbulent round jets, injected vertically upward in still water, was studied both theoretically and experimentally, including mean and fluctuating phase velocities.

TL;DR: In this article, the dispersion of discrete particles transported by the turbulence fields predicted by the Tchen theory is modeled based on an Eulerian approach, where the (monodispersed) particles are considered as a continuous field for which a transport equation is written.

TL;DR: In this paper, the volume-averaged form of the linear momentum conservation equations for two-phase flow is examined to clarify momentum interaction effects between phases, and the interphase force model is applied to predict experiments on void propagation in bubbly flows.

TL;DR: In this paper, the authors present a theoretical model describing the important physical phenomena taking place in both gaseous and solid phases in such two-phase, unsteady, reactive-flow systems.

TL;DR: In this article, the second part of a two-part study reporting structure measurements in bubbly turbulent round jets in a still environment is compared with three theoretical approaches: (1) locally homogeneous flow analysis, where velocity differences between the phases were neglected; (2) deterministic separated flow analysis where relative velocity was considered but bubble/turbulence interactions were ignored; and (3) stochastic separated Flow Analysis, where both relative velocity and bubble and turbulence interactions were considered using random-walk methods.

TL;DR: In this article, the authors measured the flooding limits in countercurrent air-water flow through pipe elbows consisting of an upper vertical leg and a lower leg which is horizontal or slightly inclined, and found that flooding is caused by unstable wave formation (slugging) at the hydraulic jump which forms in the lower pipe limb close to the bend.

TL;DR: In this paper, the singularity method was used to solve the boundary value problem for ellipsoid suspensions and the Faxen laws for the same class of spheroids.

TL;DR: In this paper, an experimental investigation of upward gas-liquid slug flow in a vertical pipe in 15 mm ID has been carried out, where the electrochemical method which permits the determination of the value and direction of instantaneous wall shear stress as well as the mean and fluctuating components of the liquid velocity is used for measurements.

TL;DR: In this paper, the authors measured the pressure differences between pipe inlet and run, Δp 1−2, and inlet branch, Δ p 1−3, for air-water and steam-water flow in a T- junction with equal diameters and a horizontal, vertical upward or downward branch.

TL;DR: In this article, the properties of a von Karman vortex street are examined theoretically for bubbly flow around a rectangular obstacle, and the effect of relaxation to local Weber number equilibrium in a transport equation for the time and space variations of bubble-number density is examined.

TL;DR: In this paper, the authors investigated the two-phase flow and heat transfer characteristics around a body including the unknown complicated flow behavior, and the most noticeable phenomena in the wake were that the peaks of the local void fraction appeared in the vicinity of the cylinder surface near the separation point and behind the cylinder.

TL;DR: Forced flow and natural circulation void fraction data for steam-water upflow in a 73.9 mm pipe were presented in this paper, showing that burst retardation is due to bubble retardation at a nearby upstream bend.

TL;DR: In this paper, the Taitel & Dukler theory and the intermittent flow model as modified by Nicholsonet al. were compared with experimental measurements of flow patterns in upward inclined pipes.

TL;DR: In this paper, an optical method is applied to measure the average velocity of solid particles transported vertically by a turbulent air stream, which is based on cross-correlating the signals of two photo-sensors.

TL;DR: In this article, the trajectories of solid particles which are raised from a dust deposit after the passage of a weak shock wave are explored by computations and compared with available experiments, showing that a particle lifted beyond the shock boundary layer loses lift force, reenters the growing boundary layer, and moves toward the floor.

TL;DR: In this article, the authors developed a theoretical model by which the flooding limits for this elbow geometry can be predicted, assuming that a smooth stratified flow exists in the lower limb of the elbow, with a free outfall at the exit Flooding is assumed to coincide with slug formation just downstream of the bend where the liquid depth is greatest.

TL;DR: The behavior of the uniform field, point-electrode electromagnetic flowmeter with two-phase flows is discussed in this article, where it is emphasized that the signal is dependent on the velocity profile and on the degrees of uniformity and isotropy of the suspension.

TL;DR: In this article, the rotational and translational velocities of a sphere moving parallel to a plane wall were determined experimentally as a function of wall-sphere separation.