Flow In Horizontal Pipe Research Articles

Experimental Investigation of Effect of Flow Conditions on Pressure Drop of Two Phase Oil (D130)-Water Flow in Horizontal and Vertical 6-inch Annulus Pipe

The flow of oil-water in pipes commonly occurs in oil and petroleum industries and is a challenging issue. Clear understanding of the frictional pressure drop (FPD) of oil-water flows in pipes is important for determining size of pumps and pipelines in transportation of oils. An experimental investigation has been conducted for measurement of pressure drop of oil Exxsol (D130)-water two-phase flow in 6 inch diameter horizontal and vertical stainless steel annulus pipe at different flow conditions. Two-phase large scale horizontal & vertical flow loop was used to acquire data for different water cuts and fluid mixture (oil-water) flow rates. Experiments were carried out for different water cuts (WC) ranging from 0-100% and for different inclination angles (0° and 90°). The oil-water flow rates were varied from 2,000 to 12,000 barrels-per-day (BPD). Exxsol mineral oil (D130) and potable water have been used as working fluids. In order to simulate field conditions, the range of liquid flow rates used matches the range of actual flow rates in oil wells. The frictional pressure drop (FPD) has been found to decrease initially (for all flow rates) from WC=0% to WC=20%. Further increase in WC, causes FPD to increase from WC=20% to WC=40%. This is due to phase inversion. For a given WC=40%, for increase in BPD from 6,000 to 8,000, increase in FPD is about 34%. The effect of angle has found to be appreciable. For a given flow rate 8,000 BPD & WC=40%, for increase in angle from 0 to 90°, percentage increase in frictional pressure drop is about 26%. The outcomes of the study will be helpful in mitigating multi-phase flow problems in oil and petroleum industries.

Turbulent heat transfer of highly buoyant supercritical CO2 flow in various horizontal pipes

Supercritical CO2 (sCO2) is considered as an ideal heat transfer fluid for power cycles adapted to a wide range of heat sources. This paper employs computational approach based on Reynolds-Averaged Navier-Stokes (RNAS) modelling to study highly buoyant turbulent sCO2 flow and heat transfer heated in various horizontal tubes with diameter of 4.57 mm, 13.39 mm, and 22.14 mm. The conditions with relatively high ratio of heat flux q to mass flux G are simulated. The chosen AKN k − ε low-Reynolds number turbulence model is rigorously validated against experiments and DNS covering a wide range of operation conditions and exhibits quite satisfactory consistencies on the strong buoyancy reproductions of horizontal supercritical flows. With sCO2 heat transfer data presented, details about the coupled turbulent flow characteristics have been discussed. It has been observed that in various size horizontal geometries, not only the local sCO2 heat transfer along the tube top surface, but also the overall performance within the liquid-like region near Tpc is greatly degraded by the strong buoyancy, and the deterioration regime expands with decreasing pipe diameter. For the highly buoyant horizontal sCO2 flows, a backflow vortex appears near the top wall then a second velocity peak forms which locates further into the core flow section for larger diameter pipes; The radial velocity profile of the top wall has been flattened even distorted into “half-M” shape that the turbulence statistics decline remarkably then the turbulent activities and thermal advection are attenuated. With sCO2 heated into the gas-like regime, the heat transfer recovers because of the reduced buoyancy effects.

Effect of specularity coefficient on hydrodynamic behaviors of slurry flows in horizontal pipes

The Eulerian–Eulerian two-fluid model (TFM) in combination with the kinetic theory of granular flow (KTGF) and the Johnson and Jackson boundary condition is widely used to simulate multiphase flows in engineering. However, this model requires the calibration of several parameters. One of these parameters is the specularity coefficient, which characterizes the particle–wall collisions. Thus far, research on this parameter has been lacking in the field of slurry flow simulations. In this study, the integration of TFM with KTGF and the Johnson and Jackson boundary condition is used to simulate the transportation of sand–water slurry in horizontal pipes. The effects of different specularity coefficient values on the predicted solids wall shear stress, velocity, and concentration are analyzed. It is found that the solids wall shear stress increases with the specularity coefficient and is more sensitive to the smaller specularity coefficient. As the specularity coefficient increases, the profiles of the solids velocity and concentration are rotated clockwise, shifting the maximum velocity point to a higher vertical location and producing a plumper solids concentration profile. These qualitative conclusions may be used as a reference for the specularity coefficient tuning process in the field of slurry transport simulations.

Detection and optimization of viscous oil viscosity and vissity reducer in alx gas well

The optimum viscosity of heavy oil is the key index to maintain the normal production of gas wells. This paper designs a new detection and optimization method of visit oil visibility and visibility reducer in alx gas well. Firstly, through the flow pattern criterion and flow pattern distribution diagram of gas-liquid two-phase flow in horizontal pipe, the propagation velocity of wave in the downstream is determined by extreme value method, and the maximum viscosity equation of heavy oil carried by air in annular fog state is established. Then, according to the maximum viscosity equation, the maximum viscosity of the heavy oil carried by the gas flow is 513.7 MPa. Finally, taking alx gas well as an example, 11 kinds of viscosity reducer were selected from water-based viscosity reducer and oil-based viscosity reducer. Under the conditions of wellhead temperature of 9 ° C and bottom hole temperature of 34 ° C, five samples with different concentrations were mixed with heavy oil, the rheological properties of the sample set were tested, and the rheological parameters and apparent viscosity of heavy oil were calculated. The experimental results show that low dosage of oil-based tackifier can effectively reduce the viscosity of heavy oil, and the optimal dosage range is 22% to 25%.

Flow Pattern Recognition Based on the Received Waveforms of a Clamp-on Ultrasonic Flowmeter for Wet Steam Flows

Clamp-on ultrasonic flowmeter is a powerful tool for measuring flow rate in an existing pipe. However, measuring flow rate of wet steam flow has not been established yet. It is important to investigate the various error factors caused by the wetness fraction. Based on our previous investigations, it was clarified that the error of the flow rates tends to increase with the wetness fraction because of the changes in the velocity distribution in the wet steam and the effect of the liquid holdup. Therefore, it is important to estimate the flow regime of the wet-steam flow in the pipe. This study proposed a flow pattern recognition method using a machine learning based on the guided wave that is the propagated ultrasound through the pipe wall. The guided wave changes depending on the flow regime due to the fluctuations at the liquid-gas interface. Using the received ultrasonic signals of the guided wave in stratified flow, annular mist flow, and transition between them were used as the teaching data, and the other conditions were tested for the flow pattern recognition. Flow patterns were accurately predicted in adiabatic air-liquid two-phase and wet-steam flows in horizontal pipes. Furthermore, it was shown that the selection of the guided wave region is important to predict the flow pattern in various pressure conditions using the same teaching data.

Experimental Analysis of the Influential Factors Upon Mixed Convection Flow in Horizontal Pipes

Experimental Analysis of the Influential Factors Upon Mixed Convection Flow in Horizontal Pipes

Ultrasonic Measurement of Two-Dimensional Liquid Velocity Profile Using Two-Element Transducer

The flow field or multidimensional velocity distribution of the coolant in fuel rod bundles of the reactor core in pressurized water reactors (PWRs) is an important parameter that is revealed through experimental investigations. This paper presents the two-dimensional (2D) velocity profile measurement using a two-element ultrasonic transducer with both elements acting as a transceiver. The size of the transducer is minimized for compactness, leading to a narrow sound field appropriate for applications in fuel rod bundle flow. Furthermore, the transducer’s sound pressure is evaluated via simulations and experimental measurements. In order to confirm the ability of the ultrasonic velocity profiler (UVP) with a two-element transducer, the experimental measurement is conducted in turbulent horizontal pipe flow. The 2D velocity vector profile is obtained, and then the measurement in swirling flow is conducted. The 2D velocity profile in an axial and radial plane is obtained utilizing the UVP measurement. Lastly, the ability of the UVP to derive the 2D velocity profile in the narrow area of the rod bundles is demonstrated.

Numerical investigation on ice slurry flow in horizontal elbow pipes

Ice slurry has been put into use as secondary refrigerant in many industrial fields due to its promising characteristics. But the complex flow properties of ice slurry flow have brought significant difficulties to transport processes. In this paper, a CFD-PBM coupled model has been employed to investigate the flow characteristics of the ice slurry flow in horizontal various elbow pipes. The ice kinetics processes (growth, aggregation, and breakage) are all taken into consideration. The results show that different elbow angles affect the pressure, velocity, ice size and uniformity of ice slurry when flowing across the elbow. Longer length and higher bending angle of elbow make boundary layer separation and secondary flow more obvious. For the elbow angle less than 90°, the redistribution of pressure and velocity enhance the aggregation process at pipe section center at elbow outlet sections, which results in the growth of ice particles. The inlet velocity, ice packing fraction (IPF) and elbow angle both influence the uniformity of ice slurry. Inlet velocity has positive correlation, while IPF and elbow angle have reverse effect. In order to improve the efficiency of ice slurry transport process and avoid the ice blockage, higher velocity, lower IPF and suitable elbow angle (less than 90°) are suggested.

Experimental investigation of different simulated formation water salinity in three-phase waxy crude oil-water-gas flow in horizontal pipes

Three-phase oil-water-gas flow experiments have been conducted in a horizontally configured rig made of carbon steel pipe with an ID of 0.041 m and a total length of 24.3 m. The test fluids were Malaysian waxy crude oil from Malay basin and three concentrations of simulated formation water salinity, namely 0 ppm, 15 000 ppm, and 30 000 ppm. The waxy crude oil and simulated formation water are varied at six different superficial liquid velocities ranging from 0.5 to 3.0 m/s while the gas phase is varied at 10 different superficial velocities ranging from 0.01 to 0.61 m/s. Eight flow patterns are observed using observational method; one of which is a newly discovered flow pattern identified as Slug with Oil Film-Oil Continuous (SLOF-OC). Salinity does not give significant effect on oil-gas interface but significantly affects the oil-water interface as lower formation water salinity is dispersed easily in crude oil compared to higher formation water salinity. The highest pressure gradient recorded was 2506.84 Pa/m at the highest superficial gas velocity while the lowest pressure gradient recorded was 89.53 Pa/m at the lowest superficial gas velocity. It is imperative to note that the experimental investigation of Malaysian waxy crude oil with different formation salinity in the three-phase flow study is in an unchartered area, therefore it provides a new platform for furthering more complex research works such as four-phase flow (gas, oil, water, and wax particles) below Wax-Appearing Temperature (WAT).

The influence of the coefficient of restitution on flow regimes within horizontal particle-laden pipe flows

Numerical simulations of the particle-laden gas–solid flow in horizontal circular pipes have been used to identify the role of particle collision coefficients in flow regimes within it. A four-way coupling Euler–Lagrangian approach was employed, using direct numerical simulations of the gas phase and Lagrangian particle tracking to account for the drag, gravitational and lift forces, together with particle–wall and inter-particle interactions. The influences on the flow of the mass loading ratio (Φm) and of the coefficients of restitution for collisions both between particles and the wall (ep−w) and between particles (ep−p) are assessed by examining the fluid and particle velocities, particle concentration distribution, turbulence kinetic energy, static pressure, inter-phase transferred momentum, and the secondary flow motions of both the fluid and particle phases. Three dominant flow regimes that include three sub-regimes based on their secondary flow patterns are identified, the transition between which depends on the combination of Φm, ep−w, and ep−p. Additionally, the quantitative dependence of these transitions on these three parameters is also reported for a series of Stokes and Froude numbers.

A new model for viscous oil-water eccentric core annular flow in horizontal pipes

Eccentric core-annular flow is encountered in water-lubricated transport of highly viscous oil in horizontal pipes. The core eccentricity results from the tendency of the phases to stratify due to a buoyant force that results from their different densities, whereby a shape of a circular core may not be maintained. To model such a flow configuration, a new three-zone model is proposed based on the Two-Fluid approach. The model's performance was examined by comparing its predictions with a large data set of pressure gradient and water holdup values obtained under different experimental conditions. It is shown that the proposed model enables better agreement with the data compared to other models available in the literature. Thus, the proposed approach appears to be a useful framework for modeling viscous oil-water eccentric core-annular flows. It can also be applied for other types of Newtonian/non-Newtonian or non-Newtonian/non-Newtonian liquid-liquid core flows encountered in industrial applications.

Numerical Simulation on Gas-Solid Two-Phase Flow in Horizontal Pneumatic Conveying Pipe Based on DPM Model

The determination of pipe deposition and optimum conveying velocity in pneumatic conveying has an important impact on conveying efficiency. The Euler-Lagrange method DPM model is used to analyse five different particle sizes and densities of small particles, and the flow pattern in the horizontal pipeline at different particle sizes and densities is derived from the graphs of the maximum discrete phase concentration, particle trajectory and discrete phase concentration distribution for each working condition. The simulation results show that the deposition increases with particle size and density, the optimum conveying speed increases with particle size and density, the larger the deposition, the larger the required conveying velocity. The velocity of 2 m/s can make the particles below 20μm suspended transport, the velocity of 4 m/s allows particles with a particle size of 30μm and a density of 1000 kg/m3 or less to be transported in suspension and 6 m/s allows particles with a density of 2000 kg/m3 or less to be transported in suspension. The aim is to provide a reference for the design of pneumatic conveying systems and the selection of the optimum conveying velocity.

Investigation of flow characteristics and eddy viscosity ratio for air-oil intermittent flow in horizontal pipe

Investigation of flow characteristics and eddy viscosity ratio for air-oil intermittent flow in horizontal pipe

All-regime two-phase flow modeling using a novel four-field large interface simulation approach

Two-phase flows may occur in many regimes, ranging from dispersed flow, slug or plug flow to stratified flow. To capture all those regimes with a monolithic approach, a so-called all-regime two-phase model should be developed. This paper presents such an all-regime two-phase modeling approach called Four-Field Large Interface Simulation (FF-LIS), in which we consistently consider two phases (gas and liquid) which can both be either resolved or sub-grid, resulting in four fields. The efficacy of this approach hinges on the accuracy with which the inter-scale mass, momentum and energy transfer terms between dispersed and resolved regimes are captured. In this paper, we introduce three phenomenological mechanisms to control the inter-scale transfer: absorption, break-up and coalescence. The separation of multiphase scales allows for the explicit modeling of transfer between them, whereas other methods often rely on an algebraic regime map in which transfer between scales is accounted for implicitly. We apply FF-LIS to the simulation of both bubbly and fully resolved single bubble flow, as a way of validating FF-LIS in those two two-phase limits. Next, the transfer terms are illustrated by simulation of bubbles rising in a column. As the bubble concentration increases, it is shown that a transfer from sub-grid to resolved occurs. Finally, we apply FF-LIS to the simulation of two-phase horizontal pipe flow in which the several flow regimes, depending on the superficial velocities, are recovered, and to the simulation of a plunging jet in which FF-LIS is shown to produce an entrained bubble plume. FF-LIS presents a computational platform for faithful two-phase resolved and sub-grid simulation of relevant real-world two-phase problems, and allows two-phase modelers for the explicit control on what can be resolved, and what should be sub-grid.

Modeling of void fraction and relative velocity covariance for dispersed bubbly and intermittent flows in horizontal channels

The interfacial drag force governs the momentum exchange between gas and liquid phases and is a key parameter in predicting void fraction using a one-dimensional thermal-analysis code. The interfacial drag force is formulated by the product of the overall drag coefficient and the area-averaged relative velocity between two phases. The area-averaged relative velocity for gas-dispersed two-phase flows has been formulated with the aid of the distribution parameter, which expresses the covariance due to the distributions of void fraction and mixture volumetric flux. It has been pointed out that the term due to void fraction covariance is missing in the formulation of the area-averaged relative velocity adopted in one-dimensional thermal-analysis codes. This study has been conducted to develop void fraction and relative velocity covariance models for gas-dispersed two-phase flows in horizontal pipes. The database of local void fraction distributions for horizontal bubbly flows was established, and an artificial database for intermittent horizontal flows was modeled with assumed distributions of local void fractions. The developed void fraction covariance model for gas-dispersed horizontal two-phase flows could reproduce the data with the mean relative deviation (i.e., bias) of 8.33% and the mean absolute relative deviation (i.e., random uncertainty) of 21.4%. The developed relative velocity covariance model for gas-dispersed horizontal two-phase flows could reproduce the data with the mean relative deviation (i.e., bias) of -0.265% and the mean absolute relative deviation (i.e., random uncertainty) of 7.11%.

Hydrodynamic Modeling of Oil–Water Stratified Smooth Two-Phase Turbulent Flow in Horizontal Circular Pipes

In the petrochemical industry, multiphase flow, including oil–water two-phase stratified laminar flow, is more common and can be easily obtained through mathematical analysis. However, there is limited mathematical analytical model for the simulation of oil–water flow under turbulent flow. This paper introduces a two-dimensional (2D) numerical simulation method to investigate the pressure gradient, flow field, and oil–water interface height of a pipeline cross-section of horizontal tube in an oil–water stratified smooth flow. Three Reynolds average N–S equation models (k−ε, k−ω, SST k−ω) are involved to simulate oil–water stratified smooth flow according to the finite volume method. The pressure gradient and oil–water interface height can be computed according to the given volume flow rate using the iteration method. The predicted result of oil–water interface height and velocity profile by the model fit well with several published experimental data, except that there is a large error in pressure gradient. The SST k−ω turbulence model appears higher accuracy for simulating oil–water two-phase stratified flow in a horizontal pipe.

Experimental Investigation of Oil-Water Two-Phase Flow in Horizontal, Inclined, and Vertical Large-Diameter Pipes: Determination of Flow Patterns, Holdup, and Pressure Drop

Summary Liquid-liquid phase flow in pipes merits further investigation as a challenging issue that has very rich physics and is faced in everyday applications. It is the main problem challenging the fluid flow mechanism in the oil and gas industry. The pressure gradient of liquid flow and flow pattern are still the topics of numerous research projects. In this paper, the emphasis is on further investigation to research the flow pattern, water holdup (HW), and pressure decrease for vertical, horizontal, and inclined flow directions of oil and water flows. Test section lines of 4.19-in. (106.426 mm) inner diameter (ID) and 5-m horizontal, 5-m inclined, and 5-m vertical test sections were serially connected. The experiments were conducted at 40°C using 2-cp viscosity oil and tap water, and oil density of 850 kg/m3, at the standard conditions. Fifty experiments were executed at 250 kPa at the multiphase flow test facility, with horizontal, upward (0.6° and 4°), downward (−0.6° and −4°) hilly terrain and vertical pipes. The oil and water superficial velocities were changed between 0.03 and 2 m/s. This evidence was obtained using video recordings; the flow patterns were observed, and the selection of each flow pattern was depicted for each condition. For horizontal and inclined flow, new flow patterns were documented (e.g., oil transfer in a line forms at the top of the pipeline, typically at high water rate, and water transfer at the lower part of the pipe at a high oil rate). The data were taken at each flow condition, resulting in new holdup and pressure drop. The results show that the flow rate and the pipe inclination angle have major impacts on the holdup and pressure drop performances. In the vertical flow, a clear peak was demonstrated by experiments after the superficial oil velocity reached a certain value. This peak is known as phase inversion point, where after this peak, the pressure starts declining as the superficial oil velocity increases. Also, slippage has been observed after varying inlet oil flow rates between the two phases. The experiments showed that with minor alteration in the inclination angle, the slippage was significantly changed. This study presented new experimental results (measured mainly at horizontal, inclined, and vertical flow conditions) of HW, flow pattern, and pressure drop. These findings are key evidence of the evolving oil-water and flowline estimate models.

Flow regimes within horizontal particle-laden pipe flows

This study presents numerical simulations for particle-laden gas–solid flows in horizontal circular pipes to identify the key flow regimes as a function of the main dimensionless parameters. A Euler–Lagrangian approach is employed, using direct numerical simulations (DNS) coupled with a Lagrangian particle tracking (LPT) method, to consider the drag, gravitational and lift forces on particles, as well as the effect of inter-particle collisions. The influence of the Stokes number (Sk), mass loading ratio (Φm) and Froude number (Fr) on critical flow regimes is assessed to identify conditions under which gravity bias becomes either negligible or dominant with regard to fluid characteristics and particle statistics. Three different regimes of the flow behaviour are identified, depending on the combination of these dimensionless parameters. These flow regimes are described and their dependence on these three parameters (Sk, Φm and Fr) is reported, including the significance of gravity in generating a bias on distributions of the flow statistics.

Development of a droplet size model for the separated gas–liquid flow in horizontal pipe and its application

A new model for droplet size prediction in horizontal pipes under stratified and annular flow is presented. The developed model takes into account the effects of the gas velocity, liquid velocity, pipe diameter, and developing length on the droplet size. Four experimental databases of droplet size in air-water horizontal flow under atmospheric pressure were used in the model development. The experimental flow conditions of the database covered a pipe diameter range of 2.45–24 cm, and gas and liquid Reynolds numbers ranges of 50,519–582,524 and 526–14,728, respectively. Droplet size experimental results were predicted by the proposed model with a root-mean-square error of 19.4% under stratified flow conditions, and 7.8% under annular flow conditions. Finally, the applicability of the suggested model was confirmed by benchmark calculations with SPACE code, a best-estimated safety analysis code for nuclear power plants, with experimental droplet parameters under various flow conditions.

Estimation of pressure drop of single-phase flow in horizontal long pipes using artificial neural network

Large- pressure drop and drag along the pipe route is one of the problems with fluid transfer lines. For many years, various methods have been employed to reduce the drag in fluid transmission lines. One of the best ways for this purpose is reducing friction coefficients by utilizing drag lowering materials. Experimentally by adding minimal amounts of this material at the ppm scale to the lines and reducing the drag of the flow, fluid can be pumped without the need to change the size of the pipe. In this study, the effect of carboxymethylcellulose biopolymer on the water flow reduction in a 12.7- and 25.4-mm galvanized pipe was investigated. In order to have a comprehensive analysis of process conditions, experiments were carried out with three different levels of concentrations, flow rate and temperature. Also, as a new innovation in this investigation, the outputs of the experimental data were evaluated and analyzed using the Taguchi method and neural network system, and optimized through a genetic algorithm. In this study, the highest rate of drag reduction will be achieved at 39 ° C and at a concentration of 991.6 ppm and flow rate of 1441.1L/h was 59.83% at 12.7-mm diameter.