AN EXPERIMENTAL AND ANALYTICAL STUDY ON CHF PHENOMENON APPEARING IN A BOTTOM-CLOSED VERTICAL TUBE FOR VAPOR/LIQUID DENSITY RATIO IN THE RANGE OF 0.000624-0.136

1994 ◽  
Author(s):  
Yoshiro Katto ◽  
K. Sugiyama ◽  
M. Fujita
Keyword(s):  
Analytical Study ◽  
Density Ratio ◽  
Vertical Tube ◽  
Liquid Density ◽  
Vapor Liquid

Nonlinear instability of plane liquid sheets

2000 ◽  
Vol 406 ◽  
pp. 281-308 ◽  
Author(s):  
SEYED A. JAZAYERI ◽  
XIANGUO LI
Keyword(s):  
Weber Number ◽  
Density Ratio ◽  
Perturbation Expansion ◽  
Liquid Sheet ◽  
Fundamental Wave ◽  
Liquid Density ◽  
Initial Amplitude ◽  
Nonlinear Stability Analysis ◽  
Liquid Sheets ◽  
Breakup Time

A nonlinear stability analysis has been carried out for plane liquid sheets moving in a gas medium at rest by a perturbation expansion technique with the initial amplitude of the disturbance as the perturbation parameter. The first, second and third order governing equations have been derived along with appropriate initial and boundary conditions which describe the characteristics of the fundamental, and the first and second harmonics. The results indicate that for an initially sinusoidal sinuous surface disturbance, the thinning and subsequent breakup of the liquid sheet is due to nonlinear effects with the generation of higher harmonics as well as feedback into the fundamental. In particular, the first harmonic of the fundamental sinuous mode is varicose, which causes the eventual breakup of the liquid sheet at the half-wavelength interval of the fundamental wave. The breakup time (or length) of the liquid sheet is calculated, and the effect of the various flow parameters is investigated. It is found that the breakup time (or length) is reduced by an increase in the initial amplitude of disturbance, the Weber number and the gas-to-liquid density ratio, and it becomes asymptotically insensitive to the variations of the Weber number and the density ratio when their values become very large. It is also found that the breakup time (or length) is a very weak function of the wavenumber unless it is close to the cut-off wavenumbers.

A Numerical Assessment of Carbon-Dioxide-Rich Two-Phase Flows with Dense Phases in Offshore Production Pipelines

SPE Journal ◽  
2020 ◽  
Vol 25 (02) ◽  
pp. 712-731 ◽  
Author(s):  
Marcelo de A. Pasqualette ◽  
João N. E. Carneiro ◽  
Stein Tore Johansen ◽  
Bjørn Tore Løvfall ◽  
Roberto Fonseca ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Pressure Gradient ◽  
Crude Oil ◽  
Temperature Drop ◽  
Density Ratio ◽  
Flow Simulation ◽  
Phase Identification ◽  
Liquid Density ◽  
Dense Phase ◽  
Offshore Production

Summary One-dimensional numerical simulations of carbon dioxide (CO2)-rich crude-oil flows were performed with a commercial simulator for a typical offshore production pipeline under steady-state scenarios. Mixtures with 20–50 mol% CO2 and gas/oil ratio (GOR) of 300–600 std m3/std m3 were thermodynamically modeled with the predictive Peng-Robinson (PPR78) equation of state (EOS) (Robinson and Peng 1978; Jaubert and Mutelet 2004), and fluid properties were tabulated in pressure/volume/temperature (PVT) lookup tables. Thorough analyses on the separate CO2 and GOR effects on several flow parameters (e.g., temperature drop, pressure gradient, and flow patterns) were performed. The occurrence of the simultaneous flow of liquid and an ambiguous dense phase was quantified and discussed in depth. The properties of those phases [e.g., Joule-Thomson coefficient, viscosity, interfacial tension (IFT), and gas/liquid-density ratio] along the pipeline for several mixtures and operational conditions were addressed as well. It was seen that the dense phase can be a problem for phase-identification criteria, which can affect the flow-simulation results. This was further analyzed in simple cases of horizontal and vertical flows of CO2-rich crude-oil mixtures, under key temperature/pressure conditions. Finally, comparisons were performed between the holdup and pressure-gradient results of those cases, obtained with different liquid/liquid- and gas/liquid-modeling approaches of a hydrodynamic point model of a commercial simulator.

An Empirical Correlation for Maximum Penetration Depth of a Particle Impacting on a Free Surface at its Critical Velocity Condition

2011 ◽  
Vol 361-363 ◽  
pp. 320-323 ◽  
Author(s):  
Dong Mei Liu ◽  
Geoffrey Michael Evans ◽  
Qing Lin He
Keyword(s):  
Penetration Depth ◽  
Critical Condition ◽  
High Speed ◽  
Least Squares Method ◽  
Density Ratio ◽  
Video Camera ◽  
Empirical Correlation ◽  
Liquid Density ◽  
Maximum Penetration Depth ◽  
Maximum Penetration

Film flotation is a process which consumes much lower energy than mechanical cells. The extended film flotation technique is to separate mineral mixtures by different critical impact velocities. In this study the maximum penetration depth of a particle at its critical condition was investigated experimentally and theoretically. Experiments were performed using spherical glass beads of different diameters and hydrophobicities and different liquids. The penetration depth at critical condition was recorded and measured using high speed video camera. Buckingham’s PI theorem was applied to analyse the dimensionless groups, and then an empirical correlation for penetration depth was obtained by partial least squares method. It was found that the prediction results of the empirical equation were in good agreement with the measurements. Also, the influence factors were analysed. It was noticed that the hydrophobicities of particle and particle-liquid density ratio had most significant effects on the penetration depth.

A Theoretical Study of Film Condensation in Horizontal Microfin Tubes

2001 ◽  
Vol 124 (1) ◽  
pp. 94-101 ◽  
Author(s):  
Hiroshi Honda ◽  
Huasheng Wang ◽  
Shigeru Nozu
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Flow Model ◽  
Density Ratio ◽  
Stratified Flow ◽  
Film Condensation ◽  
Vapor Flow ◽  
Liquid Density ◽  
Microfin Tubes

A stratified flow model of film condensation in helically grooved, horizontal microfin tubes has been developed. The height of stratified condensate was estimated by extending the Taitel and Dukler model for a smooth tube to a microfin tube. For the upper part of the tube exposed to the vapor flow, laminar film condensation due to the combined effects of gravity and surface tension forces was assumed. For the lower part of the tube exposed to the stratified condensate flow, the heat transfer coefficient was estimated by an empirical equation for the internally finned tubes developed by Carnavos. The theoretical predictions of the circumferential average heat transfer coefficient by the present model and previously proposed annular flow model were compared with available experimental data for five tubes and five refrigerants. It was shown that the stratified flow model was applicable to wide ranges of mass velocity and quality as long as the vapor to liquid density ratio was larger than 0.05. Comparison was also made with the predictions of previously proposed empirical equations.

Linear stability analysis of an electrified incompressible liquid sheet streaming into a compressible ambient gas

2016 ◽  
Vol 231 (10) ◽  
pp. 1849-1858 ◽  
Author(s):  
Yuxin Liu ◽  
Chaojie Mo ◽  
Lujia Liu ◽  
Qingfei Fu ◽  
Lijun Yang
Keyword(s):  
Stability Analysis ◽  
Electric Field ◽  
Linear Stability ◽  
Linear Stability Analysis ◽  
Density Ratio ◽  
Sheet Thickness ◽  
Liquid Sheet ◽  
Wave Number ◽  
Liquid Density ◽  
Ambient Gas

This article presents the linear stability analysis of an electrified liquid sheet injected into a compressible ambient gas in the presence of a transverse electric field. The disturbance wave growth rates of sinuous and varicose modes were determined by solving the dispersion relation of the electrified liquid sheet. It was determined that by increasing the Mach number of the ambient gas from subsonic to transonic, the maximum growth rate and the dominant wave number of the disturbances were increased, and the increase was greater in the presence of the electric field. The electrified liquid sheet was more unstable than the non-electrified sheet. The increase of both the gas-to-liquid density ratio and the electrical Euler number accelerated the breakup of the liquid sheet for both modes; while the ratio of distance between the horizontal electrode and the liquid-sheet-to-sheet thickness had the opposite effect. High Reynolds and Weber numbers accelerated the breakup of the electrified liquid sheet.

scholarly journals Generalized two-dimensional Lagally theorem with free vortices and its application to fluid–body interaction problems

2012 ◽  
Vol 698 ◽  
pp. 73-92 ◽  
Author(s):  
C. T. Wu ◽  
F.-L. Yang ◽  
D. L. Young
Keyword(s):  
Hydrodynamic Force ◽  
Density Ratio ◽  
Vortex Pair ◽  
The Body ◽  
Body Motion ◽  
Liquid Density ◽  
Two Dimensional ◽  
Fixed Target ◽  
Two Dimensional Flow ◽  
Neutrally Buoyant

AbstractThe Lagally theorem describes the unsteady hydrodynamic force on a rigid body exhibiting arbitrary motion in an inviscid and incompressible fluid by the properties of the singularities employed to generate the flow and the body motion and to meet the boundary condition. So far, only sources and dipoles have been considered, and the present work extends the theorem to include free vortices in a two-dimensional flow. The present extension is validated by reproducing the system dynamics or the force evolution of three literature problems: (i) a free cylinder interacting with a free vortex; (ii) the moving Föppl problem; and (iii) a cylinder in constant normal approach to a fixed identical cylinder. This work further extends the bifurcation analysis on the moving Föppl problem by including the solid-to-liquid density ratio as a new parameter, in addition to the system total impulse and the vortex strength. We then apply the theorem to the problem where a moving Föppl system is made to approach a fixed or a free neutrally buoyant target cylinder of identical size from far away. The force developed on each cylinder is examined with respect to the vortex pair configuration and the target mobility. When approaching a fixed target, a greater force is developed if the vortex pair has stronger circulation and larger structure. The mobility of the target cylinder, however, can modify the hydrodynamic force by reducing its magnitude and reversing the force ordering with respect to the vortex pair configuration found for the case with fixed target. Possible mechanisms for such a change of force nature are given based on the currently derived equation of motion.

Effect of ullage gas on sloshing, Part II: Local effects of gas–liquid density ratio

2016 ◽  
Vol 57 ◽  
pp. 82-100 ◽  
Author(s):  
M.R. Karimi ◽  
L. Brosset ◽  
J.-M. Ghidaglia ◽  
M.L. Kaminski
Keyword(s):  
Density Ratio ◽  
Liquid Density ◽  
Local Effects

Effect of ullage gas on sloshing, Part I: Global effects of gas–liquid density ratio

2015 ◽  
Vol 53 ◽  
pp. 213-228 ◽  
Author(s):  
M.R. Karimi ◽  
L. Brosset ◽  
J.-M. Ghidaglia ◽  
M.L. Kaminski
Keyword(s):  
Density Ratio ◽  
Liquid Density
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