scholarly journals MEASUREMENT OF TWO-PHASE GAS-LIQUID FLOW USING STANDARD AND SLOTTED ORIFICE

2019 ◽  
Vol 9 (4) ◽  
pp. 30-33 ◽  
Author(s):  
Barbara Tomaszewska-Wach ◽  
Mariusz R. Rząsa ◽  
Marcin Majer
Keyword(s):  
Gas Flow ◽  
Liquid Mixture ◽  
Liquid Mixtures ◽  
Continuous Phase ◽  
Measuring Instruments ◽  
Liquid Droplets ◽  
Two Phase ◽  
Flow Disturbances ◽  
Gas Measurement ◽  
Gas Liquid Flow

The differential pressure of gas measurement is very often used in industrial measurements. During the gas flow, liquid condensation often occurs. The result is that when measuring a gas flow, the gas-liquid mixture is essentially measured. Errors in the indications of measuring instruments are starting to appear due to a change in the properties of the continuous phase, which is gas. In addition, the appearance of liquid droplets leads to flow disturbances and pressure pulsations. Therefore, new methods and tools for measuring the flow of gas-liquid mixture are being sought. The work involves the use of slotted orifices for measuring gas-liquid mixtures. An analysis of the influence of the slotted orifice geometry on the measurement of the biphasic mixture stream was carried out. Standard orifice and three slotted orifices of various designs. The experiment included measuring the air flow with a small amount of water dispersed in the form of drops.

Features of spatial shock-wave flows in vapor-gas-liquid mixtures

2014 ◽  
Vol 10 ◽  
pp. 27-31
Author(s):  
R.Kh. Bolotnova ◽  
U.O. Agisheva ◽  
V.A. Buzina
Keyword(s):  
Shock Wave ◽  
High Pressure ◽  
Shock Waves ◽  
Liquid Mixture ◽  
Liquid Mixtures ◽  
Pressure Vessels ◽  
Water Mixture ◽  
Two Dimensional ◽  
Nonstationary Processes ◽  
Two Phase

The two-phase model of vapor-gas-liquid medium in axisymmetric two-dimensional formulation, taking into account vaporization is constructed. The nonstationary processes of boiling vapor-water mixture outflow from high-pressure vessels as a result of depressurization are studied. The problems of shock waves action on filled by gas-liquid mixture volumes are solved.

Numerical Simulation and Analysis of Effect of Injection Volume on Biomass Particle Cyclone Venturi Dryer

2021 ◽  
Author(s):  
Guohai Jia ◽  
Guoshuai Tian ◽  
Zicheng Gao ◽  
Dan Huang ◽  
Wei Li ◽  
...  
Keyword(s):  
High Speed ◽  
Optimization Design ◽  
Gas Flow ◽  
Continuous Phase ◽  
Temperature Fields ◽  
Maximum Pressure ◽  
Two Phase ◽  
Velocity Change ◽  
Injection Volume ◽  
Wood Debris

Abstract Cyclone venturi dryer is suitable for drying materials with large particle size and wide distribution. The working process of cyclone venturi dryer is a very complicated three-dimensional and turbulent motion, so it is difficult to be studied theoretically and experimentally. In order to study the internal flow characteristics of the biomass particle cyclone venturi dryer, the computational fluid dynamics (CFD) software was used to simulate the gas-solid two-phase flow field inside the cyclone venturi dryer. The continuous phase adopts the Realizable k-ε turbulence model and the particle phase is discrete. The effects of different injection volume on the pressure, velocity, and temperature fields inside a cyclone venturi dryer were analyzed. The results showed that the maximum pressure drop and velocity change inside the dryer were at the venturi pipe. The wet material of the cyclone venturi dryer was inhaled into the venturi contraction tube by the negative pressure formed after the highspeed airflow was ejected, thus the mixture was completed in the venturi throat. The wood debris material was mixed with the high-speed hot gas flow in the venturi throat and then sprayed into the diffusion pipe. In the diffusion pipe of venturi, the heat and mass transfer process of wet wood debris and heat flow in venturi diffusion tube was completed. It is in good agreement with the simulation results. This study can provide a reference for the optimization design of the related cyclone venturi dryer structure.

Momentum and Heat Transfer in Laminar Flow of Gas With Liquid-Droplet Suspension Over a Circular Cylinder

1967 ◽  
Vol 89 (2) ◽  
pp. 185-193 ◽  
Author(s):  
M. E. Goldstein ◽  
Wen-Jei Yang ◽  
J. A. Clark
Keyword(s):  
Heat Transfer ◽  
Circular Cylinder ◽  
Skin Friction ◽  
Gas Flow ◽  
Flow Problem ◽  
Liquid Droplet ◽  
Two Phase ◽  
Momentum And Heat Transfer ◽  
Layer Flow ◽  
Gas Liquid Flow

An analysis has been made to determine the heat transfer and friction characteristics in a two-phase (gas-liquid) flow over a circular cylinder. It is demonstrated that the resulting two-layer flow problem can be formulated exactly within the framework of laminar boundary layer theory. Two cases are studied; (1) For the parameter E greater or equal to 0.1 and the drop trajectories straight and, (2) For E less or equal to 0.1 and for any drop trajectory. Solutions obtained in power series include the local liquid-film thickness, velocity and temperature profiles, skin friction and Nusselt number. Numerical results disclose a significant increase in both heat transfer rate and skin friction over those of a pure gas flow. The theoretical prediction compares favorably with experimental results of Acrivos, et al. [1].

scholarly journals INVESTIGATION OF THE INFLUENCE TWO-PHASE FLOWS PARAMETERS ON THE EROSION WEAR OF THE GAS PIPELINES BENDS

2020 ◽  
Vol 1 (154) ◽  
pp. 240-248
Author(s):  
Ya. Doroshenko
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Particle Diameter ◽  
Continuous Phase ◽  
Gas Pipeline ◽  
Cfd Modeling ◽  
Erosion Wear ◽  
Two Phase ◽  
Software Complex ◽  
Dispersed Particles

CFD modeling (Computational Fluid Dynamics) Lagrangian approach (model DPM (Discrete Phase Model)) in ANSYS Fluent R19.2 Academic software complex investigates the influence of twophase gas flow velocity, size and flow rate of dispersed particles on the location and magnitude of gas pipeline bends erosion wear. The motion of the continuous phase was modeled by the solution of the Navier-Stokes equation and the continuity of the closed two-parameter k-ε turbulence model with the corresponding initial and boundary conditions. The motion trajectories of the dispersed particles were determined by integrating the force equations acting on each particle. The erosion wear of gas pipeline bends was modeled using the Finney equation. The studies were performed for gas flow velocities at the inlet of the bend from 4 m/s to 19 m/s, the diameters of the dispersed particles 0.005 mm, 0.01 mm, 0.05 mm, 0.1 mm, 0.5 mm and 1.0 mm and the flow rate of the dispersed particles from 0.0002 kg/s to 0.0022 kg/s. Natural gas was selected as the continuous phase, and sand was dispersed. The geometry of each of the simulated taps and the pressure at the outlet of the bend were assumed to be the same. The simulation results were visualized in the postprocessor software complex by constructing erosion rate velocity fields on gas pipeline bends. From the visualized results it is determined that the largest influence on the location of the erosion wear of the pipeline bends has the diameter of the dispersed particles and the least concentration. The influence of the two-phase gas flow parameters on the location of the field of their maximum erosion wear is determined. The graphical dependences of the maximum velocity of erosion wear of gas pipeline bends on each of the studied parameters of the two-phase gas stream are constructed. It has been determined that the diameter of the dispersed particles and the velocity of the gas stream have the greatest influence on the erosion wear of the erosion of the bends. Keywords: bend, dispersed particle diameter, dispersed particle rate, dispersed phase, erosion wear, Finney equation, gas flow rate, Lagrange approach.

Compressibility Effects in the Gas Phase for Unsteady Annular Two-Phase Flow in a Microchannel

2006 ◽  
Author(s):  
Alexandru Herescu ◽  
Jeffrey S. Allen
Keyword(s):  
Shock Wave ◽  
Gas Phase ◽  
High Speed ◽  
Gas Flow ◽  
Two Phase Flow ◽  
Flow Behavior ◽  
Flow Section ◽  
Phase Flow ◽  
Two Phase ◽  
Gas Liquid Flow

High speed microscopy experiments investigating two-phase (gas-liquid) flow behavior in capillary-scale systems, that is, systems where capillary forces are important relative to gravitational forces, have revealed a unique unsteady annular flow with periodic destabilization of the gas-liquid interface. Standing waves develop on the liquid film and grow into annular lobes similar with those observed in low-speed two-phase flow. The leading face of the lobe will decelerate and suddenly become normal to the wall of the capillary, suggesting the possibility of a shock wave in the gas phase at a downstream location from the minimum gas flow section. Visualization of the naturally occurring convergent-divergent nozzle-like structures as well as a discussion on the possibility of shock wave formation are presented.

Numerical Simulation of Particle-Gas Flow Through a Fixed Pipe, Using One-Way and Two-Way Coupling Methods

2016 ◽  
Vol 33 (2) ◽  
pp. 205-212 ◽  
Author(s):  
Z. Namazian ◽  
A. F. Najafi ◽  
S. M. Mousavian
Keyword(s):  
Numerical Simulation ◽  
Gas Flow ◽  
Volume Fraction ◽  
Fluid Velocity ◽  
Particle Volume Fraction ◽  
Stokes Number ◽  
Continuous Phase ◽  
Turbulent Pipe Flow ◽  
Particle Volume ◽  
Two Phase

AbstractA numerical simulation of the particle-gas flow in a vertical turbulent pipe flow was conducted. The main objective of the present article is to investigate the effects of dispersed phase (particles) on continuous phase (gas). In so doing, two general forms of Eulerian-Lagrangian approaches namely, one-way (when the fluid flow is not affected by the presence of the particles) and two-way (when the particles exert a feedback force on the fluid) couplings were used to describe the equations of motion of the two-phase flow. Gas-phase velocities which are within the order of magnitude as that of particles, volume fraction, and particle Stokes number were calculated and the results were subsequently compared with the available experimental data. The simulated results show that when the particles are added, the fluid velocity is attenuated. With an increase in particle volume fraction, particle mass loading and Stokes number, velocity attenuation also increases. Moreover, the results indicate that an increase in particle Stokes number reduces the special limited particle volume fraction, according to which one-way coupling method yields plausible results. The results have also indicated that the significance of particle fluid interaction is not merely a function of volume fraction and particle Stokes number.

scholarly journals Modelling of unsaturated gas flow by Thebes code: Validation tests

2020 ◽  
Vol 195 ◽  
pp. 02005
Author(s):  
Ayman Abed ◽  
Wojciech Sołowski
Keyword(s):  
Unsaturated Soil ◽  
Gas Flow ◽  
Theoretical Framework ◽  
Two Phase ◽  
Validation And Verification ◽  
Infiltration Test ◽  
Gas Liquid Flow ◽  
Validation Tests ◽  
Compositional Method

This paper presents the simulations replicating two well-documented benchmarks on coupled gas-liquid flow in unsaturated soil. The results serve as validation and verification of the formulation of the gas flow in unsaturated geomaterials in the newly developed THMC coupled FEM code Thebes. The paper first discusses the basis of the compositional method and the role of the dry air mass balance equation in the theoretical framework. The fundamental constitutive assumptions related to gas flow, as adopted in the Thebes code, are also discussed in details. Afterwards, the paper discusses simulation of a two-phase infiltration test in unsaturated sand, as well as a one dimensional drainage test. The numerical results of these two examples show that the code is able to capture the main features associated with the gas flow in unsaturated soil. The possible future improvements, both related to the theoretical framework and the numerical implementation, are discussed at the closure of the paper.

scholarly journals Fuzzy Regulator for Two-Phase Gas–Liquid Pipe Flows Control

2021 ◽  
Vol 12 (1) ◽  
pp. 399
Author(s):  
Paweł Fiderek ◽  
Jacek Kucharski ◽  
Radosław Wajman
Keyword(s):  
Gas Flow ◽  
Current Flow ◽  
Liquid Mixtures ◽  
Liquid Volume ◽  
Flow State ◽  
Two Phase ◽  
Pipe Flows ◽  
Flow Type ◽  
Input Signals ◽  
Fuzzy Regulator

The paper presents an intelligent module to control dynamic two-phase gas–liquid mixtures pipelines flow processes. The module is intelligent because it uses the algorithm based on AI methods, namely, fuzzy logic inference, to build the fuzzy regulator concept. The developed modification has allowed to design and implement the black-box type regulator. Therefore, it is not required to determine any of the complicated computer models of the flow rig, which is unfortunately necessary when using the classic regulators. The inputs of the regulator are four linguistic variables that are decomposed into two classes and two methods of fuzzification. The first input class describes the current values of gas and liquid pipe flows, which at the same time are the controlled values manipulated to generate desired flow type. The second class of the input signals contains a current flow state, namely, its name and the name preferred by the operator flow type. This approach improves the control accuracy since the given flow type can be generated with different gas and liquid volume fractions. Those values can be optimized by knowing the current flow type. Moreover, the fuzzification algorithm used for the input signals included in the first-class covers the current crisp signal value and its trend making the inference more accurate and resistant to slight measurement system inaccuracy. This approach of defined input signals in such environments is used for the first time. Considering all mentioned methods, it is possible to generate the desired flow type by manipulating the system input signals by minimum required values. Furthermore, a flow type can be changed by adjusting only one of the input signals. As an output of the inference process, two linguistic values are received, which are fuzzified adjustment values of the liquid pump and gas flow meter. The regulator looks to be universal, and it can be adopted by multiple test and production rigs. Moreover, once configured with a dedicated rig, it can be easily operated by the non (domain) technical staff. The usage of fuzzy terms makes understanding both the control strategy working principles and the obtained results easy.

Towards the Understanding of Transformation of Annular to Droplet-Annular Gas-Liquid Flow

2016 ◽  
Author(s):  
Parmod Kumar ◽  
Sushanta K. Mitra ◽  
Arup Kumar Das
Keyword(s):  
Liquid Film ◽  
Gas Phase ◽  
Gaseous Phase ◽  
Annular Flow ◽  
Clear Understanding ◽  
Gravitational Acceleration ◽  
Liquid Droplets ◽  
Two Phase ◽  
Phase Velocities ◽  
Gas Liquid Flow

Annular flow and its deviations due to change of phase velocities in parallel and counter flows are very common in many adiabatic and non-adiabatic applications of two phase flow. The transformation from annular flow to its counterpart droplet-annular flow is often poorly understood as it needs to handle multi scale interfaces experimentally or numerically. In the present work, attempts have been made to capture both wavy annular interface and dynamics of tiny droplets throughout its life cycle using grid based volume of fluid framework. 3-D simulation domain with length (L)/diameter (D) ratio as 6 is considered under the effect of gravitational acceleration and phase inertial field. Wavy interface is observed numerically between the phases using phase fraction contours along with the occurrence of three very interesting phenomena, which include rolling, undercutting and orificing. At low liquid and gas velocities orificing has been observed which restricts the path of gaseous phase. Departure from the orificing phenomenon has been seen at higher gas phase velocities which transforms to other phenomenon called rolling. Rolling is the folding of liquid film by the high velocity gaseous phase towards the radially outward direction. Further, increase in liquid phase velocities above gaseous phase velocities results in undercutting of liquid film by the gas phase. Moreover the liquid droplets can be seen in the entire phenomenon through the gas phase in the core of the tube. We presented a regime map of gas liquid velocities to segregate clear understanding of annular to droplet-annular flow due to orificing, rolling and undercutting. The present study will enrich the knowledge of multiphase flow transportation in process plants, chemical reactors, nuclear reactors and refineries where gas-liquid annular flow is most widely used flow pattern.

scholarly journals Computational Study of Two-Phase Flow Morphology in a Nozzle

2018 ◽  
Vol 3 (3) ◽  
pp. 419
Author(s):  
Balakin B.V. ◽  
Kuzmenkov D.M. ◽  
Kutsenko K.V. ◽  
Maslov Yu.A. ◽  
Saparbaeva N.A. ◽  
...  
Keyword(s):  
Gas Flow ◽  
Gamma Ray ◽  
Computational Study ◽  
Average Density ◽  
Cfd Modelling ◽  
Flow Meter ◽  
Two Phase ◽  
Flow Through ◽  
Flow Morphology ◽  
Gas Liquid Flow

Multiphase flow meters are widely used in nuclear, petroleum and chemical industries. Here the flow rate is defined indirectly by the differential pressure measurement over the device. An additional measurement is required to estimate average density of the phase mixture. This could be done by means of the gamma-ray, electromagnetic or acoustic tomography. The accuracy of the technique is dependent on flow morphology. The present paper reports the results of CFD-modelling of the gas-liquid flow through the vertical flow meter accompanied by a flow conditioner. The model is used to consider the morphology for three different combinations of liquid and gas flow rates. The model demonstrates high non-uniformities of the flow field at the entrance of the flow meter and generally confirms the agreement of flow morphology with previous experimental observations for vertical pipes. 

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