Twophase heat transfer modeling in subsea pipelines. When liquids have to be transported at relatively high temperatures, e. Two phase flow occurs frequently in chemical processing, and the design of processing equipment and piping systems requites knowledge of pressure drop, liquid holdup, and often flow pattern. Phase change heat transfer is a broad field that finds applications in almost all of the engineering disciplines. Pipeline transport is the longdistance transportation of a liquid or gas through a system of pipesa pipelinetypically to a market area for consumption. Twophase experimental heat transfer studies on a water. This paper discusses procedures for the prediction of pressure gradients, flow patterns, entrainment, and void fraction on the shell side of heat exchangers and in pipes during horizontal flow. Q, and the inlet and outlet temperatures of both fluids, thus allowing calculation of the log.
Oil and gas pipeline design, maintenance and repair. If he needs a test section of 10 ft of fully developed flow, what should be the minimum. Fluid mechanics and multiphase flow in pipelines antonio c. In process industries, twophase flow has gained importance over the years. Twophase fluid heat transfer and pressure drop principles are similar to singlephase fluids in that heat transfer coefficients and pressure drop are also a function of mass flux. Flow quality flow rate flow regime low low and intermediate bubbly high dispersed bubbly. To demonstrate the basic equations of heat exchanger operation. Twophase flowheat exchangers fundamentalsand design. Heat exchangers consist primarily of bundles of pipes, tubes or plate coils. Improper use of the overall heat transfer coefficient or heavy end characterization can lead to completely erroneous conclusions about the presence or absence of liquid, even to indicate as far as a pipeline will be handling dry gas when in reality the line will be in two phase gas liquid flow.
This paper discusses procedures for the prediction of pressure gradients, flow patterns, entrainment, and void fraction on the shell side of heat. Due to separation of the two phases in the manifolds, the gas and the liquid is distributed unequally into the heat transfer tubes. In two phase flow models, the void fraction is the key parameter for predicting flow pattern transitions, heat transfer, and pressure drops and, moreover, for determining the two phase density and. Industrial sites often have huge heat exchanger networks with several utility ows. In the nuclear industry, two phase flow occurs in reactor cooling equipment, and liquid holdup greatly affects heat transfer. Airwater is an example of two phase multi component flow. A better understanding of the rates of momentum and heat transfer in multi phase flow is a must for the optimum design of heat exchangers. Two phase flow on the shell side of a shell and tube heat exchanger is complex. Kastner 553 two phase pressure drop in boiler tubes w. Three phase flows of gas and two liquid phases often occur during production of oil. Pdf twophase flow regimes in exchangers and piping. Steven vallee, brent heyrman, doug decker and doug ducote. Influence of heat transfer on twophase flow behavior in onshore oil pipelines.
An analysis shows the effect of variation in pressure, temperature, mass flow rate, and pipe size on the pseudocritical region and the heattransfer area of the hx. 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. Box 4808, carrier parkway syracuse, ny 221 abs1racf the lmtd concept is based on the assumptions of a constant heat transfer coefficient and constant specific heat of fluids. Lmt0 applications in twophase heat transfer and twophase. Phase separation and deposition involving nucleation or initiation of fouling sites and. Shell and tube heat exchangers basic calculations pdh online. Twophase flow on the shell side of a shell and tube heat. This paper describes the problems in route optimization of two phase pipelines. Lmtd applications in two phase heat transfer and two phase heat exchangers xinliu carrier corporation, united technologies p. Heat exchangers with or without phase transition and. Distribution in a bahx, pressure drop of a single stream among multiple flow paths will always be.
Double pipe heat exchangers are the simplest exchangers used in industries. This paper deals with two phase airwater downflow in the corrugated channels commonly found in plate and frame heat exchangers. He also selects a mean flow velocity of 2 fps for the test. Modeling and optimization of multistream heat exchangers. Depending on the mass flow rate, the heat flux, and the fluid, either or both of these heat transfer mechanisms may be significant. Two phase flow heat exchangers are vital components of systems for power generation, chemical processing, and thermal environment control. In process industries, two phase flow has gained importance over the years. The characteristics of brazed plate heat exchangers with. As we will see in later chapters, a gas pipeline s capacity can be very sensitive to the wall surface roughness, and it takes only a tiny amount of droplets on the wall to affect the friction significantly. Heat transfer involving two phases such as liquidgas is of vital importance especially in petrochemical and allied industries. Designing of twophase flow heat exchangers and practice strategy of heat exchanger design j. Two micro heat exchangers, characterized by microchannels of 100 100 and 200 200 l m square cross sections, were designed for that purpose. His research activities include complex fluid flow, rheology, viscoelastic fluids, turbulent drag reduction, heat and mass transfer, emergency relief design, multiphase flow, and electrochemical engineering. Projecttwo phase flow instabilities in lng heat exchangers.
Twophase gasliquid pipe flow and relief sizing aiche. Uneven velocity profiles, backflows and eddies generated on the shell side of. Two phase gasliquid pipeline simulation campbell tip of. Designing of two phase flow heat exchangers and practice strategy of heat exchanger design j. 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. Module 12a two phase fluid flow and heat transfer rev 02. Route optimization of pipeline in gasliquid twophase flow.
Influence of heat transfer on twophase flow behavior in. A better understanding of the rates of momentum and heat transfer in multiphase flow is a must for the optimum design of heat exchangers. Since experimentation in twophase flow is cumbersome, heat transfer coefficient correlations are being developed using. Eyaporation heat transfer in general, flow boiling heat transfer takes place through two different mechanisms.
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. Twophase flow in pipelines and heat exchangers duncan. The presented model shows the effect of heat transfer in subsea pipelines for twophase fluids for normal operating and shutdown conditions. Friction factor is calculated by solving colebrook white equation. Experimental investigation of fluid flow and heat transfer in. Since experimentation in twophase flow is cumbersome, heat transfer coefficient correlations are being developed using pure fluid thermophysical properties, dimensionless numbers such as the reynolds.
Twophase flow distribution in heat exchanger manifolds. The current study has investigated twophase refrigerant. The presented model shows the effect of heat transfer in subsea pipelines for two phase fluids for normal operating and shutdown conditions. The results from the numerical model can be used to optimize the heattransfer area of the hx. This shell is specified for phase change duties where significantly. Twophase flow occurs frequently in chemical processing, and the design of processing equipment and piping systems requites knowledge of.
The type of flow in such narrow passages, which is associated with the choice of the most appropriate flow model for cfd simulation, is still an open issue in the literature. He selects a 1inchdiameter pipe and uses a glycerinwater mixture as the fluid, which has a kinematics viscosity equal to i04 ft2s. Types of phase flows and gas liquid system piping guide. Understanding heat exchangers types, designs, applications and. Albrecht 495 postchf heat transfer in boiler tubes w. A study of twophase flow in inclined pipes onepetro. In twophase flow, as with singlephase, creating radial movement in the boundary layer and in the bulk flow will enhance the rate of heat transfer. In recent years, two phase flow induced vibration fiv has been given increasing attention in various engineering fields including petroleum pipelines, power and processing plants, heat exchangers, as well as in the nuclear power plant components altstadt et al.
Taborek 473 elements of twophase flow in fossil boilers j. In the first book in this series, pipe flow 1 single phase flow assurance, we observed that dealing with single phase pipe flow is relatively easy in most cases, and the methods for predicting how the fluid behaves are quite mature. The uid used was deionized water and there was no phase change along the uid circuit. In recent years, twophase flow induced vibration fiv has been given increasing attention in various engineering fields including petroleum pipelines, power and processing plants, heat exchangers, as well as in the nuclear power plant components altstadt et al. In counterflow heat exchangers the fluids enter the exchanger from opposite. Threephase flows of gas and two liquid phases often occur during production of oil.
Argonwater is an instance of two phase two component flow. Background a heat exchanger is a heat transfer device whose purpose is the transfer of energy from one moving fluid stream to another moving fluid stream. Since the highpressure side of the vapor compression cycle can have a condenser or a gas cooler, for which there is no twophase. Twophase flow on the shell side of a shell and tube heat exchanger is complex. 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. In two phase flow, as with single phase, creating radial movement in the boundary layer and in the bulk flow will enhance the rate of heat transfer.
In fluid mechanics, twophase flow is a flow of gas and liquid a particular example of multiphase flow. As oil is extracted from the reservoir, the formation water beneath may flow into the well, due to its easier motion through the rock pores. Combining the hydraulic calculation with route optimization theory, this paper establishes an automatic route optimization model and adopts the general genetic algorithm gga and steadystate genetic algorithm ssga to solve the model, respectively, gets the optimal route, and discusses the influence of. The heat exchanger is characterized by four input values and two output. Notes on twophase flow, boiling heat transfer, and. Dec 14, 2015 todays blog entry relates to heat transfer from liquids flowing in longdistance buried pipelines. A form of shell and tube heat exchanger, double pipe heat exchangers.
Source terms from twophase flow in long pipelines following. A wide range of models have been developed for twophase flow systems. The results from the numerical model can be used to optimize the heat transfer area of the hx. Plug flow occurs when the liquid phase forms a nearly continuous phase with large elongated bubble plugs of gas located within the liquid phase. Combining each of these resistances in series gives. A wide range of models have been developed for two phase flow systems. Uneven two phase distribution reduces the thermal performance of compact heat exchangers with parallel flow circuits.
Develop a novel modeling and simulation framework of heat exchangers considering two phase flow instabilities and transient phenomena. Godwin in association with institution of chemical engineers, 1983. Twophase flow distribution in compact heat exchanger. If even a small amount of liquid condenses on the pipe wall, it will affect the flow. Experimental data have been acquired in a heat exchanger test rig specially made for measurement of mass. The developed heat transfer model combines the application of twophase heat transfer coefficient model with fluid properties obtained from a low dimensional fluid model developed by our group. Lmt0 applications in twophase heat transfer and two. In singlephase heat exchangers, the fluids do not undergo any phase.
The engineers developed the terminology rather than the chemists. Todays blog entry relates to heat transfer from liquids flowing in longdistance buried pipelines. Hybrid flow heat exchangers exhibit some combination of the characteristics of the. The art and science of the design of such heat exchangers have advanced considerably in recent years.
Transient phenomena in liquidgas flow in pipelines zohra ouchiha, s. Several studies have produced flow pattern maps that show surprising differences in flow regime boundaries for data. This article focuses on heat exchangers, exploring the various designs and types available. T l average temperature in crosssection of pipeline at distance l, k. This paper describes the problems in route optimization of twophase pipelines. Bubble or froth flow bubble or froth flow like the plug flow, has a dominant liquid phase, but the liquid phase in bubble flow is at a higher velocity than the liquid phase in plug flow. Uneven twophase distribution reduces the thermal performance of compact heat exchangers with parallel flowcircuits. The presence of a gas phase along with liquid alters not only the fluid dynamic behavior but also the heat transfer characteristics namely, the heat transfer coefficient. An analysis shows the effect of variation in pressure, temperature, mass flow rate, and pipe size on the pseudocritical region and the heat transfer area of the hx. Heat exchangers 73 individual thermal resistances of the system. Lmtd applications in twophase heat transfer and twophase heat exchangers xinliu carrier corporation, united technologies p. To understand the basic operation of heat exchangers. Twophase flow and pressure drop in flow passages of compact. Home fluid flow fluid flow single phase this web application calculates pressure drop in a straight pipe due to flow of a single phase incompressible fluid based on darcy weisbach equation.
In the nuclear industry, twophase flow occurs in reactor cooling equipment, and liquid holdup greatly affects heat transfer. Twophase flow heat exchangers are vital components of systems for power generation, chemical processing, and thermal environment control. Kastner 553 twophase pressure drop in boiler tubes w. Bannwart state university of campinas, brazil keywords. With this configuration, the maximum heat capacity is due to the phase change of the heat pipe working fluid. Boiling and condensation are two of the most important phase change processes as they are generally associated with high heat transfer rates.
Since experimentation in two phase flow is cumbersome, heat transfer coefficient correlations are being developed using. A critical assessment of twophase flow distribution in. Box 4808, carrier parkway syracuse, ny 221 abs1racf the lmtd concept is based on the assumptions of a constant heat. In the first book in this series, pipe flow 1 singlephase flow assurance, we observed that dealing with singlephase pipe flow is relatively easy in most cases, and the methods for predicting how the fluid behaves are quite mature. Twophase flow in pipelines and heat exchangers chisholm, d on. A multistream heat exchanger mhex is a single process unit in which. The developed heat transfer model combines the application of two phase heat transfer coefficient model with fluid properties obtained from a low dimensional fluid model developed by our group. Systematic experimental study of two phase flow instabilities in a single and in parallel chanels.
The flow channel consists of a transparent plastic plate to allow. Twophase flow distribution in plate heat exchanger and. As we will see in later chapters, a gas pipeline s capacity can be very sensitive to the wall surface roughness, and it takes only a tiny amount of droplets on the wall to. His research activities include complex fluid flow, rheology, viscoelastic fluids, turbulent drag reduction, heat and mass transfer, emergency relief design, multi phase flow, and electrochemical engineering. This fact leads to the analysis of the heat pipe heat exchangers as two separate heat exchangers coupled by the heat pipe working fluid, which is similar to a liquidcoupled indirecttransfer heat. Modeling and simulation of the double tube heat exchangers. Taborek 473 elements of two phase flow in fossil boilers j. The mechanisms of boiling and condensing vary from application to application.
A typical oil and gas reservoir contains gas, oil and water. The latest data from 2014 gives a total of slightly less than 2,175,000 miles 3,500,000 km of pipeline in 120 countries of the world. Two phase flow in pipelines and heat exchangers chisholm, d on. Being able to reduce the number of heat exchangers by applying multistream heat exchangers can improve both the capital and operating costs of chemical process plants.
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