Estimation of Gas and Liquid Flow Rates in Gas-Liquid Two-Phase System

2002 ◽  
Author(s):  
Koji Mori ◽  
Tetsumasa Ono ◽  
Masuo Kaji ◽  
Toru Sawai
Keyword(s):  
Gas Phase ◽  
Liquid Flow ◽  
Annular Flow ◽  
Water System ◽  
Phase System ◽  
Two Phase ◽  
Flow Rates ◽  
Mean Values ◽  
Pressure Drops ◽  
Flow Channels

A new method of estimating gas and liquid flow rates is proposed for a gas-liquid two-phase flow system. The method involves measurement of pressure drops in horizontal and vertical flow channels, and calculation of flow rates by Lockhart-Martinelli correlation. The method does not require the insertion of sensing device into the flow channel and does not rely on previously calibrated correlations. Experiments are performed in slug, froth and annular flow regimes for an air-water system, and the usefulness of the proposed method is examined. The results reveal that gas and liquid flow rates can be estimated with the accuracies of 45% for gas phase and 37% for liquid phase with respect to mean values.

scholarly journals Hydrodynamics and axial mixing in a packed gas-liquid column

2003 ◽  
pp. 33-48
Author(s):  
Branislava Barjaktarovic ◽  
Milan Sovilj ◽  
Svetlana Popovic
Keyword(s):  
Pressure Drop ◽  
Gas Phase ◽  
Liquid Flow ◽  
Packed Column ◽  
Packed Bed ◽  
Axial Dispersion ◽  
Gas Absorption ◽  
Phase System ◽  
Two Phase ◽  
Gas Phases

The objective of this study was to investigate the pilot-plant gas absorption packed column hydrodynamics, as well as axial mixing in the system air-water. The pressure drop and the gas phase holdup data were determined in dependence on the flow rates of gas and liquid phases. The influence of superficial velocities of liquid and gas phases on the liquid axial dispersion in a gas-liquid packed bed column (ID 15 cm) consisting of Raschig rings (15x15x2 mm) were investigated. The pressure drop was measured with a U-type manometer, connected to the bottom and the top of the working part of the column. The gas phase holdup data in the air-water two-phase system was calculated as a ratio of the gas phase volume to the total volume of the two-phase system. Axial dispersion in the water phase has been determined by examining of the distribution of residence times of a salt tracer (NaCl) in the packed bed. The tracer was injected in the liquid flow above the packed bed; samples of liquid were simultaneously taken from two sites at 1 m distance along the bed. Salt concentrations in the samples were determined by conductivity measurements. The mean residence time and the axial dispersion number were calculated by the moment method. The axial dispersion increases with an increase of liquid flow velocities and decrease of superficial air velocities.

Gas-Agitated Liquid-Liquid Extraction in a Spray Column

1994 ◽  
Vol 59 (10) ◽  
pp. 2235-2243 ◽  
Author(s):  
Milan Sovilj ◽  
Goran Kneževic
Keyword(s):  
Gas Phase ◽  
Liquid Extraction ◽  
Hydrodynamic Characteristics ◽  
Extraction Column ◽  
Phase System ◽  
Two Phase ◽  
Flow Rates ◽  
Liquid Liquid Extraction ◽  
Three Phase ◽  
Phase Water

The hydrodynamic characteristics of the air water toluene three-phase system in a spray extraction column at 20 °C were examined. The average and local hold-up data of the dispersed phase were determined in dependence on the flow rates of the continuous, dispersed and gaseous phases. The average gas phase hold-up was also measured and analyzed. A comparison was made of the hydrodynamic characteristics of the two-phase (water - toluene) and three-phase (air - water - toluene) systems.

Numerical modeling of the influence of bubbles on flow and heat transfer in the descending gas-liquid flow in a pipe

2012 ◽  
Vol 9 (1) ◽  
pp. 131-135
Author(s):  
M.A. Pakhomov
Keyword(s):  
Heat Transfer ◽  
Gas Phase ◽  
Liquid Flow ◽  
Bubble Diameter ◽  
Gas Content ◽  
Two Phase ◽  
Eulerian Description ◽  
Flow And Heat Transfer ◽  
Gas Liquid Flow ◽  
The Mathematical Model

The paper presents the results of modeling the dynamics of flow, friction and heat transfer in a descending gas-liquid flow in the pipe. The mathematical model is based on the use of the Eulerian description for both phases. The effect of a change in the degree of dispersion of the gas phase at the input, flow rate, initial liquid temperature and its friction and heat transfer rate in a two-phase flow. Addition of the gas phase causes an increase in heat transfer and friction on the wall, and these effects become more noticeable with increasing gas content and bubble diameter.

The effect of two-phase flow regime on hydrodynamics and mass transfer in a horizontal-tube gas-liquid reactor

1985 ◽  
Vol 50 (3) ◽  
pp. 745-757 ◽  
Author(s):  
Andreas Zahn ◽  
Lothar Ebner ◽  
Kurt Winkler ◽  
Jan Kratochvíl ◽  
Jindřich Zahradník
Keyword(s):  
Mass Transfer ◽  
Pressure Drop ◽  
Flow Regime ◽  
Liquid Flow ◽  
Horizontal Tube ◽  
Liquid Holdup ◽  
Two Phase ◽  
Flow Rates ◽  
Type Relation ◽  
Good Agreement

The effect of two-phase flow regime on decisive hydrodynamic and mass transfer characteristics of horizontal-tube gas-liquid reactors (pressure drop, liquid holdup, kLaL) was determined in a cocurrent-flow experimental unit of the length 4.15 m and diameter 0.05 m with air-water system. An adjustable-height weir was installed in the separation chamber at the reactor outlet to simulate the effect of internal baffles on reactor hydrodynamics. Flow regime maps were developed in the whole range of experimental gas and liquid flow rates both for the weirless arrangement and for the weir height 0.05 m, the former being in good agreement with flow-pattern boundaries presented by Mandhane. In the whole range of experi-mental conditions pressure drop data could be well correlated as a function of gas and liquid flow rates by an empirical exponential-type relation with specific sets of coefficients obtained for individual flow regimes from experimental data. Good agreement was observed between values of pressure drop obtained for weirless arrangement and data calculated from the Lockhart-Martinelli correlation while the contribution of weir to the overall pressure drop was well described by a relation proposed for the pressure loss in closed-end tubes. In the region of negligible weir influence values of liquid holdup were again succesfully correlated by the Lockhart-Martinelli relation while the dependence of liquid holdup data on gas and liquid flow rates obtained under conditions of significant weir effect (i.e. at low flow rates of both phases) could be well described by an empirical exponential-type relation. Results of preliminary kLaL measurements confirmed the decisive effect of the rate of energy dissipation on the intensity of interfacial mass transfer in gas-liquid dispersions.

A Developed Numerical Method for Turbulent Unsteady Fluid Flow in Two-Phase Systems with Moving Interface

2017 ◽  
Vol 14 (06) ◽  
pp. 1750063 ◽  
Author(s):  
A. M. Hegab ◽  
S. A. Gutub ◽  
A. Balabel
Keyword(s):  
Numerical Model ◽  
Gas Phase ◽  
Level Set ◽  
The Body ◽  
Phase System ◽  
Computational Domain ◽  
Two Phase ◽  
Moving Interface ◽  
Level Set Function ◽  
Gas System

This paper presents the development of an accurate and robust numerical modeling of instability of an interface separating two-phase system, such as liquid–gas and/or solid–gas systems. The instability of the interface can be refereed to the buoyancy and capillary effects in liquid–gas system. The governing unsteady Navier–Stokes along with the stress balance and kinematic conditions at the interface are solved separately in each fluid using the finite-volume approach for the liquid–gas system and the Hamilton–Jacobi equation for the solid–gas phase. The developed numerical model represents the surface and the body forces as boundary value conditions on the interface. The adapted approaches enable accurate modeling of fluid flows driven by either body or surface forces. The moving interface is tracked and captured using the level set function that initially defined for both fluids in the computational domain. To asses the developed numerical model and its versatility, a selection of different unsteady test cases including oscillation of a capillary wave, sloshing in a rectangular tank, the broken-dam problem involving different density fluids, simulation of air/water flow, and finally the moving interface between the solid and gas phases of solid rocket propellant combustion were examined. The latter case model allowed for the complete coupling between the gas-phase physics, the condensed-phase physics, and the unsteady nonuniform regression of either liquid or the propellant solid surfaces. The propagation of the unsteady nonplanar regression surface is described, using the Essentially-Non-Oscillatory (ENO) scheme with the aid of the level set strategy. The computational results demonstrate a remarkable capability of the developed numerical model to predict the dynamical characteristics of the liquid–gas and solid–gas flows, which is of great importance in many civilian and military industrial and engineering applications.

Hydraulic Model Calibration of a Nuclear Plant Service Water System

2016 ◽  
Author(s):  
Erin A. Onat ◽  
Trey W. Walters ◽  
David M. Mobley ◽  
James J. Mead
Keyword(s):  
Water System ◽  
Complete Data ◽  
Second Phase ◽  
Data Set ◽  
Flow Rates ◽  
Pressure Drops ◽  
Calibration Process ◽  
Partial Data ◽  
Service Water ◽  
Data Calibration

As pipe networks age, build-up [scaling] and corrosion decrease pipe diameter and increase pipe roughness, leading to significant pressure drops and lower flow rates. When modeling the hydraulics of these systems, calibrating the pipes to account for additional scaling and/or fouling can be vital to accurately predicting the hydraulic behavior of the system. An automated, multi-variable goal-seeking software was used to calibrate the raw water system of the Duke McGuire Nuclear Station (MNS). This calibration process involved three phases. The first phase was the testing of the automated, multivariable goal-seeking software on a previously calibrated system. The second phase was the calibration of a partial data set. The third phase was the calibration of a complete data set. The automated goal-seeking software was found to have varying degrees of success in each phase. At the conclusion of the calibration process, the partial data calibration of two parallel systems at MNS yielded average overall calibration accuracies of 2.1% and 1% for flow rates, and 1.2 psig (8.4 kPa-g) and 1.7 psig (11.9 kPa-g) for pressures. The complete data calibration of one of these systems at MNS yielded an average overall calibration accuracy of 2.3% for flow rates, and 1.4 psig (9.5 kPa-g) for pressures.

Prediction of Two-Phase Pressure Drop and Density Distribution From Mixing Length Theory

1963 ◽  
Vol 85 (2) ◽  
pp. 137-150 ◽  
Author(s):  
S. Levy
Keyword(s):  
Single Phase ◽  
Continuous Medium ◽  
Phase System ◽  
Mixing Length ◽  
Test Results ◽  
Two Phase ◽  
Pressure Drops ◽  
Mixing Length Theory ◽  
Phase Pressure ◽  
Good Agreement

Single-phase turbulent mixing length methods are used to predict two-phase flow. Two-phase density and velocity distributions and two-phase pressure drops are derived by treating the two-phase system as a continuous medium where the turbulent exchanges of momentum and density are equal. Good agreement is obtained between test results and analytical predictions.

Cross-Sectional Imaging of the Liquid Film in Horizontal Two-Phase Annular Flow

Volume 3 ◽  
2004 ◽  
Author(s):  
Daniel J. Rodri´guez ◽  
Timothy A. Shedd
Keyword(s):  
Film Thickness ◽  
Liquid Film ◽  
Liquid Flow ◽  
Annular Flow ◽  
Laser System ◽  
Excitation Wavelength ◽  
Two Phase ◽  
Cross Sectional ◽  
Annular Regime ◽  
The Waves

Planar laser induced fluorescence (PLIF) was applied to horizontal air/water two-phase annular flow in order to clearly image the liquid film and interfacial wave behavior at the top, side and bottom of the tube. The visualization section was fabricated from FEP, which has nearly the same refractive index as water at room temperature. This index-matched test section was used to allow imaging of the water to within approximately 10 microns of the 15.1 mm I.D. tube wall. A small amount of dye was added to the water with a peak excitation wavelength near that of a pulsed Nd:YAG laser (532 nm). The laser system generated an approximately 5 ns pulsed light sheet at 30 Hz. Images of the liquid film were captured using a digital video camera with a macro lens for a resolution of about 8.2 microns/pixel. Cross-sectional data at 68 annular flow conditions were obtained. The observations of the liquid film between waves indicated that the film thickness was relatively insensitive to both gas and liquid flow in the annular regime, confirming film thickness measurements reported elsewhere. In addition, the structure of waves changes significantly from wavy-annular, where peaked or cresting waves dominate, to fully annular, where the waves are much more turbulent and unstructured. The wave height decreases with increased gas flow and is relatively insensitive to increased liquid flow in the annular regime. The entrainment of gas in the liquid by the waves is very apparent from these images. Although the precise entrainment mechanisms are not entirely clear, a viable folding action mechanism is proposed. The visualization results will be discussed in relation to both conceptual and computational annular flow modeling.

Unified Model for Gas-Liquid Pipe Flow Via Slug Dynamics: Part 2 — Model Validation

2002 ◽  
Author(s):  
Hong-Quan Zhang ◽  
Qian Wang ◽  
Cem Sarica ◽  
James P. Brill
Keyword(s):  
Experimental Data ◽  
Liquid Flow ◽  
Pipe Flow ◽  
Flow Behavior ◽  
Two Phase ◽  
Flow Rates ◽  
Inclination Angles ◽  
Gas Liquid Flow ◽  
Extensive Experimental Data ◽  
Good Agreement

In Zhang et al. [1], a unified hydrodynamic model is developed for prediction of gas-liquid pipe flow behavior based on slug dynamics. In this study, the new model is validated with extensive experimental data acquired with different pipe diameters, inclination angles, fluid physical properties, gas-liquid flow rates and flow patterns. Good agreement is observed in every aspect of the two-phase pipe flow.

Geothermal Reservoir Simulation Using Nonequilibrium Thermodynamics

1983 ◽  
Vol 23 (04) ◽  
pp. 613-622
Author(s):  
V.V. Nguyen ◽  
G.F. Pinder
Keyword(s):  
Porous Media ◽  
Finite Difference ◽  
Nonequilibrium Thermodynamics ◽  
Fluid Pressure ◽  
Water System ◽  
Alternative View ◽  
Phase System ◽  
Two Phase ◽  
Preliminary Results ◽  
Geothermal Reservoirs

Abstract A phenomenological interpretation of the evolution of a steam/water system is proposed from a nonequilibrium mixture perspective. This type of thermodynamic behavior is structurally stable on the basis of catastrophe theory and therefore offers an unorthodox alternative approach to the simulation of geothermal reservoirs. Use of this approach in a one-dimensional (ID) finite-difference simulator yields results that can be compared with a traditional numerical scheme. Introduction All numerical simulators of geothermal reservoirs depend on an accurate representation of the thermodynamics of the steam/water system. This information is required to render tractable the system of balance equations derived from the physics of flow through porous media. While it is generally recognized that the porous media. While it is generally recognized that the two-phase system is not in thermodynamic equilibrium, equilibrium thermodynamics is universally employed in its description for numerical simulators (see Ref. 1 for a state-of-the-art review of these models). In this paper, we present an alternative view on nonequilibrium thermodynamics. A phenomenological investigation of the proposed approach has been reported by Nguyen at From this new perspective, we constrict a computational scheme that eliminates the difficulties often encountered in the two-phase region. Preliminary results of this work were reported by Preliminary results of this work were reported by Nguyen and Pinder. This study provides a description of a ID mathematical model of two-phase hydrothermal flow, an outline of the finite-difference procedure employed to approximate its solution. and a concise summary of the proposed nonequilibrium thermodynamics theory for the proposed nonequilibrium thermodynamics theory for the steam/water system. Also included are the computation scheme for the phase-transition problem and a numerical simulation that uses the experimental conditions given by Arihara et al. Governing Equations The equations describing unsteady I D flow in a horizontal two-phase hydrothermal system have been developed by several authors, and the derivation methods are not repeated here. These equations have the following forms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (1) and . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (2) where p is fluid pressure and h is enthalpy of the fluid mixture., and are nonlinear coefficients defined as follows. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (3) SPEJ p. 613

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