A study of twophase flow in inclined pipes onepetro. Distribution of two phase flow in a distributor 45 journal of engineering science and technology february 2012, vol. One of the aspects that play a role in the acoustics in pipes is the in. The flow physics inside the pipe was solved using computational fluid dynamics cfd solver ansys fluent.
Two phase flow is any type of flow containing more than one phase of liquid, gas or solid. Pdf numerical analysis of two phase flow patterns in. A comprehensive mechanistic model for upward twophase. Guidelines for line sizing for two phase flow in horizontal pipe checalc chemical engineering calculations to assist process, plant operation and maintenance engineers. Vertical two phase flow geometries can be classified as bubble, slugannular, transition, and annularmist, depending on the gasliquid ratio.
Flow regimes and phase equilibrium phase equilibrium is obtainable at a constant pressure. As in our own bodies, where the veins and arteries move blood through the pumping. Laminar flow is characterized by little mixing of the flowing fluid and a parabolic velocity profile. Nonflashing lines have two phase flow, and carry both condensate and steam from the equipment to the trap. Depending upon the flow regime, the liquid in a two phase flow system can be accelerated to velocities approaching or exceeding vapour velocities. There are many applications in the chemical and process industries, ranging from the flow of mixtures of oil and gas. Multiphase flow assurance the free version of the book is for your personal and noncommercial use only. Twophase fluid flow guideline to pipe sizing for twophase flow liquid gas author. Relief valves for twophase gas liquid flow, chemical engineering, 109, no. The simultaneous flow of oil and water in pipelines is a common occurrence in the petroleum industry. This is mainly because the reliable measurements of the two phase. Two phase flow experiments were performed with airwater mixtures in a small rectangular channel measuring 9. Modeling of twophase flows in horizontal tubes core. Pdf on sep 1, 2007, ahad ghaemi and others published modeling two phase flow in horizontal pipe bends find, read and cite all the research you need on researchgate.
Model based on experiments with airwater flow for various pipe inclinations. Flow of helium ii, or of electrons in a superconductor, thought of as consisting of two interpenetrating, noninteracting fluids, a superfluid component which exhibits no resistance to flow and is responsible for superconducting properties, and a normal component, which behaves as does an ordinary fluid or as conduction electrons in a nonsuperconducting metal. Results and discussion the experimental conditions are plotted on flow pattern maps as shown in figs. Introduction critical two phase flow can occur when liquid and gas phase mixture leaks from a pipe or a vessel at a higher pressure to a pipe, a vessel or an atmosphere at a lower pressure through an opening. Numerical simulation of twophase flow regime in horizontal. Chemical engineers frequently encounter the flow of a mixture of two fluids in pipes. Actually, the terms twocomponent flow and twophase flow are. Combining previous both expressions gives an equation for the upper limit. Thus, slug flow constitutes the most serious implication in two phase flow. In addition, when gasliquid mixtures flow at high velocities serious erosion problems can arise and it is necessary for the designer to restrict flow velocities to avoid serious damage to equipment.
The fact that each phase in the two phase flow problem has its own properties, velocity, and temperature makes the solution of two phase flow and heat transfer problems very challenging. The design of two phase liquidgas pipe flow systems is a complex process. Slug flow belongs to a class of intermittent flow that has very distinctive features and it occurs under special circumstances of two phase gasliquid flow. Twophase flow is a difficult subject principally because of the complexity of the form in which the two fluids exist inside the pipe, known as the flow regime. Many researches were carried out to correlate differential pressure and void fraction in two phase. Braga 5 evaluated air and water flow in a pipe with 1250 meters length. The general geometry of horizontal pipe flow for the case studies modeled is shown in figure 4.
The need for two phase flow measurement in the power generation industry has been significantly increased over the last few years. Correlations for liquid holdup and friction factor were developed for predicting pressure gradients for two phase flow in pipes at all angles for many flow pressure gradients for two phase flow in pipes at all angles for many flow conditions. A relatively recent diffuseinterface model for multi phase flow systems is based on phase fields, long used in materials science problems. When these two states act in randomlike manner, unstable flow starts occurring in the form of oscillations and or flow reversals, inducing pressure and velocity fluctuations, resulting in undesirable mechanical vibration of components in piping system. This lecture discusses about different flow patterns possible in gasliquid flow through horizontal and vertical pipes including phase change applications. A new prediction model for frictional pressure drop of two phase flow in pipes. The two phases can exist as combinations of solid, gas andor liquid phases. Department of chemical and biomolecular engineering. Many correlations have been developed for predicting two phase flow pressure gradients which differ in the manner used to calculate the three terms of pressure. Two phase flow liquidgas system design may 21, 2019 martin king. This webinar covers methods for identifying flow regimes and determining friction loss in two phase distributed and homogeneous gasliquid pipe flows and sizing relief valves for frozen and flashing homogeneous two phase flow. This equation is usually adapted for two phase flow by assuming that the two phase flow regime and two phase properties can be considered homogeneous over a finite volume of the pipe. There are two basic flow regimes for flow of a singlephase fluid. Hydraulic fluid flow two phase calculations engineering.
Twophase fluid flow guideline to pipe sizing for two phase flow liquid gas author. Typical plots of velocity time histories for laminar flow, turbulent flow, and the region of transition between the two are shown below. This may be true for pumped return lines, but not for nonflashing or flashing lines. Search for library items search for lists search for contacts search for a library. Multiphase flow is important in many areas of chemical and process. Talk on elements of twophase flows with emphasis on. Two phase flow literature reports a plethora of correlations for determination of flow patterns, void fraction, two phase pressure drop and nonboiling heat transfer correlations. Studies will be made on how to express losses caused by a change in the cross sectional area of a pipe, a pipe bend and a valve, in addition to the frictional loss of a pipe. Mean volumetric void fraction is a key parameter to characterise two phase flows. Frictional pressure drop of gas liquid twophase flow in pipes. The average velocity of gas phase flow ug is defined as the volumetric flow rate of gas phase q g divided by the pipe crosssectional area occupied by the gas phase flow ag. In the homogeneous model, the two phases are assumed to be travelling at the same velocity in the channel and the flow is treated as being analogous to a single phase flow see article on multiphase flow. Argonwater is an instance of two phase two component flow.
Pdf during twophase gasliquid flow in pipelines, the fluids may take. The fluid dynamic characteristics of a liquid and air mixture are extremely complex, and to a large degree are still. Pdf in order to understand the behaviour of twophase flow in inclined pipes, an extensive programme of work has been undertaken using the inclinable. Actually, the terms two component flow and two phase flow are often used rather loosely in the literature to mean liquidgas flow and liquidvapor flow respectively. Liquidliquid twophase flow systems neimabrauner school of engineering, telaviv university telaviv 69978, israel 1 generaldescriptionofliquidliquidflows. Pdf gasliquid twophase flow in inclined pipes researchgate. Twophase flow refers to the interactive flow of two distinct phases with common interfaces in a channel, with each phase representing a mass or volume of matter. Such high velocities can cause a phenomenon known as erosion corrosion in equipment and piping systems. Twophase flow studies in horizontal pipes with special reference. However, the influence of the relative roughness becomes more evident at higher vapour quality and higher mass flux. Types of gasliquid flow bakers map for gasliquid flow calculation methodology references 3. This map is based on a semitheoretical method, and it is computationally more difficult to use than other flow maps. Pdf modeling twophase flow in horizontal pipe bends.
Airwater is an example of two phase multi component flow. Two phase flow models comparison and analysis yun zhe liu 3520 2. Liquidgas or liquidvapor mixtures are encountered in condensers and evaporators, gasliquid reactors, and. Water fractions in the output stream increase materially during the producing life of a well and many wells exist from which economic production can still persist with water volume fractions in the liquid phase in excess of 90%.
Their respective distribution takes on some commonly observed flow structures, which are defined as two phase flow patterns that have particular identifying characteristics. Depending upon the flow regime, the liquid in a twophase flow system can be accelerated to velocities approaching or exceeding vapour velocities. In fluid mechanics, twophase flow is a flow of gas and liquid a particular example of multiphase flow. Void fraction measurement of gasliquid twophase flow from. Identify two phase separated flow regimes in horizontal and vertical pipe flows.
Bubble flow, slug flow and emptyfullempty flow in fluid applications duration. The two phase flow patterns in vertical flow are somewhat different from those occurring in horizontal or slightly inclined flow. Two phase flow splitting in piping branches by michael steven quintana s. Micro motion coriolis flow and density measurement 2,997. The design of two phase pipe flow systems is often a complex phenomenon. The engineers developed the terminology rather than the chemists. Pressure drop and flow pattern definition data were obtained over a large range of mass qualities. Twophase gasliquid pipe flow and relief sizing aiche. Although their operational condition was a single phase flow in turbulent condition, the presented method of analysis on pipe elbow can be applicable to two phase flow, especially for bubbly flow case since the flow field in that regime is governed by the liquid phase, which creates pressure fluctuations due to secondary flow and dean vortex. Pressure variations are inevitable in most two phase. A gas lift option is also included with the program. Flow of the liquid may be viscous and phase is assumed to flow alone, and phase, must. Notes on twophase flow, boiling heat transfer, and. My goal for this lecture is to lay down basic terminology for two phase flow, and give a feeling for what various void fractions represent.
In some cases these velocities are higher than desirable for a process piping system. Flow type the flow type of two phase liquidgas flow can be characterized into one of seven types shown. Pdf of void fraction that showed traditional features of slug flow one peak at lower void. Twophase flow and pressure drop in flow passages of compact. Flowpatterns flows of two immiscible liquids are encountered in a diverse range of processes and. A comprehensive model is formulated to predict the flow behavior for upward two phase flow. Types of phase flows and gas liquid system piping guide. Two phase flow horizontal pipe line sizing and pressure drop calculation for two phase fluid flowing through a horizontal pipe. Any flow involving two of the three phases is a twophase flow.
A local velocity which has a constant mean value but also has a statistically random fluctuating component due to turbulence in the flow. These processes are frequently encountered in the process industries. The result demonstrated that the frictional pressure drop increases with increasing relative roughness of the pipe. Gasliquid twophase flow regimes for vertical pipes. The separated flow model considers the two phases to be artificially separated into two streams, each flowing in its own pipe.
A fractional phasefield model for twophase flows with. Two phase flow models can be classified into two types. The transition from horizontal to vertical pipe causes disruptions in the flowfield resulting in flow induced unsteady forces as well as additional losses in. Gasliquid flow in inclined pipes was investigated to determine the erect of pipe inclination angle on liquid holdup and pressure loss. Flow quality flow rate flow regime low low and intermediate bubbly high dispersed bubbly intermediate low and intermediate plugslug. Understanding the challenges of two phase flow 2 phase flow is difficult for all flowmeters all flow meter technologies have limitations, and most have a tough time with two phase flow, such as air mixed in a liquid stream. Numerical methods such as volumeoffluid 3,4 and levelset 4,5 have been successfully employed to simulate two phase flows. Study on oilwater twophase flow in horizontal pipelines. Notes on twophase flow, boiling heat transfer, and boiling. A computational fluid dynamics study of two phase dispersed flow of viscous oil and water in a horizontal pipe. Actually, the terms two component flow and twophase flow are often used rather loosely in the literature to mean liquidgas flow and liquidvapor flow respectively. Although the wall elasticity is negligible for very stiff steel pipes that are. Some engineers believe that condensate return pipes are completely filled with condensate. This pressure becomes important for designing pipe sizes, determining pump requirements, and addressing safety concerns.
A few other empirical correlations are used to describe the multiphase flow through the choke. Elements of two phase flows with emphasis on liquid vapour phase change phenomenon by pradeep kumar. Two phase flow article about two phase flow by the free. Pdf simplified transient twophase model for pipe flow. The discharge of twophase flashing flow in a horizontal duct. A wide range of models have been developed for two phase flow systems. Study of twophase flow in pipe bends by jose ramon castillo submitted to the department of mechanical engineering on may 20, 1957, in partial fulfillment of the requirements for the degree of master of science.
Pdf effect of flow patterns on twophase flow rate in vertical pipes. Correlations for liquid holdup and friction factor were developed for predicting pressure gradients for two phase. Flow quality flow rate flow regime low low and intermediate bubbly high dispersed bubbly. Leung, twophase flow discharge in nozzles and pipes a unified approach, journal of loss prevention in the process industries, 1990, 3, 1, 27crossref. May 09, 2011 two phase flow in a pipe simulated with openfoam. In this study, adiabatic airwater two phase flow experiments in a 203. For two phase flow, the respective distributions of the liquid and vapor phases in the flow channel is the important aspect of their description. Nazario, twophase flashing flow methods and comparisons, journal of loss prevention in the process industries, 1990, 3, 2, 253crossref. The most common twophase flow regime is called slug flow, in which pipe cross section is filled alternatively with gas and liquid. However, the validity of a majority of these correlations is restricted over a narrow range of two phase flow conditions. Void fraction measurement of gasliquid twophase flow.
The areas of the two pipes are proportional to the void fraction. The areas of the two pipes are proportional to the void fraction numerous. Iost of the scientific investigation of twophase flow has been conducted in. Introduction some of the important features of the flow of two phase mixtures composed of a liquid together with a gas or vapour are discussed in this section. The multiphase flow in wellbores and pipe lines is handled by several multiphase flow equations including beggsbrill, hagedornbrown, hasankabir, and duns and ros. A comprehensive mechanistic model for upward two phase flow in wellbores a. Downward two phase flow in large diameter pipes appears in numerous industrial applications and nuclear reactor accidents. Fluidflow is used by engineers to calculate pressure losses and flow distribution in two phase pipe flow. Processes in power systems involve various forms of two phase flow, and it is specially important when dealing with accident scenarios in nuclear power plants. Flashing lines also have two phase flow carrying both drained. Two phase flow in piping system significance and usage. Chapter 3 flow analysis memorial university of newfoundland. Twophase flow can occur in various forms, such as flows transitioning from pure liquid to vapor as a result of external heating, separated flows, and dispersed twophase flows where one phase is present in the form of particles, droplets, or bubbles in a continuous carrier phase i.
It can be common practice for engineers to use template design calculation sheets for two phase systems. You may not modify, copy, distribute, transmit, display, reproduce, publish, license, create derivative works from, transfer, or sell any information from the book. The subject of multiphase flows encompasses a vast field, a host of different technological. Prediction of optimum length to diameter ratio for twophase fluid. Using the homogeneous flow pressure drop method, calculate the two phase pressure drop for up flow in a vertical tube of 10 mm internal diameter that is 2 m long. Theoretical evaluation of twophase flow in a horizontal. Slug flow occurs when the dispersed gas bubbles combine to form bigger bubbles. Two phase flow analyses are critical to successful design and operations of two phase and multiphase pipe flow applications found in major industrial fields, such as petroleum, nuclear, chemical. Experimental investigation of twophase flows in large. A study of two phase flow in inclined pipes, jpt may 1973, 607617. Toward the end of these notes, well see some examples of these regimes.
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