Flow In Horizontal Pipeline Research Articles

Experimental Study for Enhancement of Water Flow in Horizontal Pipelines by Using Nanoparticles of Zinc Oxide and Poly Acrylic Acid

Experimental Study for Enhancement of Water Flow in Horizontal Pipelines by Using Nanoparticles of Zinc Oxide and Poly Acrylic Acid

IMPROVEMENT OF METHODS FOR CALCULATION OF GAS-LIQUID SLUG OF FLOW IN PIPELINES

To calculate pressure losses during transportation of gas-liquid fluids in flowlines, it is important to correctly estimate the effective density and viscosity of the mixture, which increases the accuracy of calculating the tangential stresses required to determine hydraulic pressure losses at the liquid-wall boundary. The determining parameter when calculating the effective values of the density and viscosity of the mixture is the coefficient liquid holdup in the cross section of the pipeline. The article analyzes the applicability of empirical methods for modeling two-phase gas-liquid currents when calculating liquid holdup in slug body of a intermittent (slug) flow in horizontal pipelines. A description is given of the mechanistic approach proposed by Zhang to calculate the liquid holdup in the slug body used in one of the most famous modern models of gas-liquid flow — TUFFP Unified model. The results of calculating the actual liquid holdup in the slug body using the TUFFP Unified model hydrodynamic model are presented, showing good consistency of the calculated data with experimental ones for vertically located pipelines, and unsatisfactory consistency for currents in horizontal pipes. The purpose of the article is to improve the methods of calculating the gas-liquid slug structure of the current using the TUFFP Unified model, by improving the accuracy of calculating the liquid holdup in the slug body at the horizontal location of the flowline. The proposal to use in the TUFFP Unified model a new approach to assessing the stable diameter of the gas bubble of the dispersed-bubble flow regime in the body of a liquid slug made it possible to increase the reliability of calculating the liquid holdup in the slug body with a horizontal location of the pipeline.

Numerical simulation of two-phase slug flows in horizontal pipelines: A 3-D smoothed particle hydrodynamics application

A fundamental difficulty of studying gas–liquid pipe flows is the prediction of the occurrence and characteristics of the slug flow regime, which plays a crucial role in the safety design of oil pipelines. Current empirical methods and one-dimensional computational models only achieve limited success. While 3-D numerical simulations are highly recommended, they have been very seldom used. We perform 3-D Lagrangian numerical simulations of gas–liquid pipe flows by adapting an existing multi-phase smoothed particle hydrodynamics (SPH) method based on a Riemann solver to achieve an efficient solver. To realize the high inlet velocities of gas and liquid an in- and outlet boundary condition is presented. The results are validated against existing experimental data, numerical simulations and analytical solutions. Multiple gas–liquid pipe flow patterns are predicted, namely, smooth stratified, stratified wavy, bubble flow, slug flow and bubble flow. Several principle characteristics of slug flows, e.g., pressure gradient, slug development and slug frequency are analyzed in a 3-D fully Lagrangian framework.

Numerical analysis of particle injection effect on gas-liquid two-phase flow in horizontal pipelines using coupled MPPIC-VOF method

Pipeline transport of three-phase (gas, liquid, and solid particles) flows has become increasingly prevalent in various industrial applications. Due to complicated fluid phase interactions, experimental and numerical investigation of this type of flow can be very demanding. In this study, the coupled Eulerian–Lagrangian approach MPPIC-VOF is adopted, which is capable of capturing solid particle motion as well as fluid phase development simultaneously. Prior to three-phase flow simulation, two-phase air–water flow in a specific range of gas and liquid superficial velocities with slug and plug flow patterns is simulated. Then, polypropylene particles are injected as the solid phase into the air–water flow and the effects of particles on pressure drop, void fraction, and flow patterns are studied. The pressure drop and void fraction results are validated for both two-phase and three-phase flows by different correlations and experimental results. As a result of particle injection at the low concentration of 0.5%, void fraction increases by 13.7% and pressure drop changes on average by 18%, respectively. However, there was no significant change in the flow patterns.

Pressure Drop Prediction Model of the Gas-Liquid Stratified Flow Development Section in the Horizontal Pipeline

Abstract The gas phase accelerating beyond the liquid phase caused by gas-liquid slippage cannot be ignored in short horizontal pipelines with undulation and inflow, and there is no method to calculate it. Therefore, a pressure drop prediction model for variable liquid holdup was developed in this paper. The theoretical model calculation results were validated using computational fluid dynamics. The effectiveness of the pressure drop prediction model has been demonstrated. The various pressure drop, liquid holdup, and development length laws were then examined. The findings indicate that: the pressure drop in the developed section of stratified flow is not only the friction pressure drop but also the acceleration pressure drop; the length of the stratified flow development section and pipeline pressure drop are more easily affected by the flowrate than the liquid holdup in the pipe inlet. Using the relevant data from coalbed methane horizontal wells as an example, the L/D of the development section is approximately 40–85 when the inlet flowrate is 0.8–1 m/s, and the inlet liquid holdup is 0.3–0.5. The pressure drop characteristics in the gas-liquid stratified flow development section are obviously different from those in the stable section. The development of a pressure drop prediction model for the stratified flow development section lays the theoretical groundwork for the investigation of gas-liquid two-phase flow in horizontal pipelines with short or undulating and inflow conditions.

Experimental investigation of maldistribution characteristics of gas‐liquid two-phase flow in a horizontal pipeline

In the flow distribution of oil and gas gathering and transportation system, the flow pattern, inertia force, gravity, and other factors will lead to uneven flow distribution of each outlet pipe, which will seriously affect the economy and safety of the gathering and transportation system. Therefore, it is of great significance to analyze the characteristics of gas–liquid two-phase flow in horizontal pipelines. For this reason, an experimental device for maldistribution control of gas–liquid two-phase flow is developed in this article. In order to solve the problem of flow maldistribution in gas–liquid two-phase flow pipe, the test experiments of maldistribution control under the conditions of three flow patterns (stratified flow, slug flow, and annular flow) are carried out. Through experiments, we revealed the control law of flow pattern to liquid maldistribution and gas maldistribution with or without flute pipes and formed the maldistribution control scheme of gas–liquid two-phase flow in the horizontal pipeline. It is found that it is more beneficial to the control of average liquid maldistribution degree under the condition of slug flow pattern in horizontal manifold without flute pipe, and it is more beneficial to the control of average gas maldistribution degree under the condition of annular flow pattern without flute pipe. Without the function of the flute pipe and in the annular flow pattern, it is beneficial to the control of average maldistribution degree of gas–liquid two-phase flow. The findings of this research can be used as a reference for the field maldistribution control of oil and gas gathering and transportation systems.

Flow Pattern Identification of Oil-Water Two-Phase Flow Based on SVM Using Ultrasonic Testing Method.

A flow pattern identification method combining ultrasonic transmission attenuation with an ultrasonic reflection echo is proposed for oil–water two-phase flow in horizontal pipelines. Based on the finite element method, two-dimensional geometric simulation models of typical oil–water two-phase flow patterns are established, using multiphysics coupling simulation technology. An ultrasonic transducer test system of a horizontal pipeline with an inner 50 mm diameter was built, and flow pattern simulation experiments of oil–water two-phase flow were carried out in the tested field area. The simulation results show that the ultrasonic attenuation coefficient is extracted to identify the W/O&O/W dispersion flow using the ultrasonic transmission attenuation method, and the identification accuracy is 100%. By comparison, using the ultrasonic reflection echo method, the echo duration is extracted as an input feature vector of support vector machine (SVM), and the identification accuracy of the stratified flow and dispersed flow is 95.45%. It was proven that the method of the ultrasonic transmission attenuation principle combined with the ultrasonic reflection echo principle can identify oil–water two-phase flow patterns accurately and effectively, which provides a theoretical basis for the flow pattern identification of liquid–liquid multiphase flow.

Identifying the mechanism of the mixed-phase flow in the horizontal pipeline using computational fluid dynamic approach

In this study, computational analysis has been carried out using computational fluid dynamics (CFD). These calculations have been made to investigate the rheological behavior of the mixed-phase flow in horizontal pipelines. In order to study the shear stress in a vertical pipe, a new numerical model for oil-water dispersion in three dimensions has been developed. CFD software has been used to study the wall shear stress function and water droplet pressure. Using Reynolds numbers and the Navier-Stokes equations with k–turbulence factor to save energy, the flow range for the continuous process was explained. The results from a recent study on experimental methodology were simulated. In this study, the diameter of the tube is 40 mm and the length is 3.5 m and modeled and analyzed using Ansys software. Thus, the geometry has been imported and modeled using the CFD tool. The meshed model has been tested and converged accordingly. The primary data of the simulation have been verified with experimental results successfully. Oil droplet widths have previously been thought to be dependent on the flow Reynolds number, which was confirmed in this case study. Droplet diameter Dd was measured at 6 mm while the mixture moved at a speed of 1.9 m/s. It was found that the largest shear stress value was found at the top of the pipe, where the oil fraction (cut-off) was 0.3, in the simulation results for varied velocities (1.6, 2.5, 2.9 m/s) and oil fraction (cut-off) values. The results of the simulation analysis of the two-phase flow of crude oil for the horizontal pipe are wall shear stresses with different velocities for crude oil in the two-phase flow. As well as pressure drop at different velocities for the same fluids

CFD Simulation of Turbulent non-Newtonian Slurry Flows in Horizontal Pipelines

CFD Simulation of Turbulent non-Newtonian Slurry Flows in Horizontal Pipelines

Experimental Analysis of Flow Characteristics and Annular Flow Boundaries of the Highly Viscous Oil/Water Lubricated Flow

Summary Theoretical research on the characteristics of two-phase flow in horizontal pipelines is very important in the petroleum industry because a large amount of pumping power can be derived from the water-lubricated transportation of heavy or extraheavy crude oil. Experimental research of oil/water two-phase flow with water as the continuous phase in horizontal pipelines is carried out using tap water and two mineral oils with viscosity of approximately 0.743, 412, and 686 mPa·s, respectively. Two oil/water mixing devices of a water-ring generator and T-shaped three-way pipe are adopted to compare the effect of oil/water annular flow. Pressure drop parameters, apparent viscosity, clear pictures, flow pattern maps, and resistance characteristics of oil/water two-phase flow are displayed in this article, together with comprehensive comments. Moreover, obtained results are compared with theoretical findings, experimental results, and empirical laws of different scholars in the literature. According to the ratio of fluid kinetic energy (inertial force) to potential energy (buoyancy), Froude number (Fr) is introduced to reach the state of hydrodynamic lift balance. Based only on experimental observations of the position of the layered/annular transition, a novel criterion is proposed to determine the regions with suitable operating conditions for application.

Effect of solid particles on the slug frequency, bubble velocity and bubble length of intermittent gas–liquid two-phase flows in horizontal pipelines

New experimental data are presented in this study for intermittent two and three-phase flows through horizontal pipelines involving air, water and polypropylene pellets of sizes ranging between 1 and 2 millimeters. Flow visualization and pressure measurements were performed and are explored in this work for intermittent flows. An automated image processing algorithm is developed to determine slug parameters of 59 flow conditions and compared with other measurements techniques. Correlations available in the literature for predicting slug frequency are tested with the new experimental data and curves of non-dimensional parameters are fitted to the data, the best fitting is obtained for the gas based Strouhal number against the input liquid or gas fraction. The influence of solid particles over the slug frequency is analyzed and reported. A decrease on the slug frequency is found when increasing solid concentrations. Finally, the influence of solid particles on the bubble length and velocity is investigated. A stronger influence of the gas flow rate on the velocity of the nose of the slug is observed for increasing solid concentration, together with more variability on the mean velocity. Also, longer bubbles are obtained with higher solid concentrations.

Heavy oil-water dispersed flows in horizontal pipelines using bio-additives with energy analysis: Experimental and numerical investigations

Heavy oil and water dispersed flows in a 0.0254 m, 0.0381 m, 0.0508 m ID horizontal pipelines (Pipeline length = 2.5 m) were investigated experimentally and numerically (at steady state) without and with additives by varying the temperature from 25 °C to 50 °C by considering power law (i.e., for emulsion) rheological behavior. The development of boundary layer, pressure drop, velocity profile, boundary layer thickness, and wall shear were discussed in these numerical investigations without and with water, ML (i.e., a natural extract from Madhuca Longifolia), and PS (i.e., potato starch) via pipeline transportation of heavy oil. The pressure drops in the numerical simulations were compared with the available experimental results and found in qualitative agreement (i.e., max error ±7%). The pressure drop from the inlet to the outlet was decreased with an upsurge in the concentration of bio-additives in the aqueous phase of the heavy oil emulsion and temperature. The development of the boundary layer was significantly varied after adding water and bio-additives to the heavy oil. The ratio of boundary layer thickness and pipe length is reduced by increasing the additive's temperature and concentration in the heavy oil-water flows. Furthermore, the reduction in wall shear occurred after efficiently adding water and bio-additives to the heavy oil during transportation. The comparative studies also carried out between the influence of additives on the hydrodynamic parameter. The bio-additives (ML and PS) in the aqueous phase improve the hydrodynamics of heavy oil flow in the pipeline. Natural extract ML improves the hydrodynamics of heavy oil flow through the pipeline than potato starch. The application of numerical investigations can significantly enhance understanding the hydrodynamics of the heavy oil/emulsion's transportation via pipelines with greater accuracy for complex pipeline configurations.

The Impact of Swirls on Slurry Flows in Horizontal Pipelines

In deep ocean transportation pipeline, the swirling internal flow has a significant impact on the marine minerals transportation efficiency and safety. Therefore, the present work investigates various swirl flow motions for the slurry transport characteristics of the multi-sized particulate flow in a horizontal pipeline. Since the internal flow is a liquid-solid-solid mixture, a steady-state three-dimensional Eulerian-Eulerian multiphase approach in conjunction with the k-ω SST turbulence model is implemented for numerical simulation in the commercial CFD software ANSYS FLUENT 17.0. Numerical predictions of the mixture solid concentration distributions are generally in good conformance with experimental measurements. It is clearly revealed the transition of flow regime from heterogeneous to pseudo-homogeneous with the increasing level of swirl intensity at inlet. Compared to non-swirling flow, the swirling flow is of benefit to the multi-sized solid suspension capacity and the transportation efficiency. Moreover, the intense swirling vortex results in a strong influence on the characteristics of the lubrication layer formed by fine solid particles near the bottom of the pipe. These results provide valuable insights regarding the influence of swirl flow on the transport process for deep ocean mining.

Low Pressure Experimental Validation of Low-Dimensional Analytical Model for Air–Water Two-Phase Transient Flow in Horizontal Pipelines

This paper presents a low-pressure experimental validation of a two-phase transient pipeline flow model. Measured pressure and flow rate data are collected for slug and froth flow patterns at the low pressure of 6 bar at the National University of Singapore Multiphase Flow Loop facility. The analyzed low-dimensional model proposed in comprises a steady-state multiphase flow model in series with a linear dynamic model capturing the flow transients. The model is based on a dissipative distributed parameter model for transient flow in transmission lines employing equivalent fluid properties. These parameters are based solely on the flowing conditions, fluid properties and pipeline geometry. OLGA simulations are employed as an independent method to validate the low-dimension model. Both low-dimensional and OLGA models are evaluated based on the estimated two-phase pressure transients for varying gas volume fraction (GVF). Both models estimated the two-phase flow transient pressure within 5% mean absolute percent error of the laboratory data. Additionally, an unavoidable presence of entrained air within a pipeline is confirmed for the case of 0% GVF as evidenced by the pressure transient estimation. Thus, dampened oscillations in the simulated 0% GVF case exists owing to an increase in the fluid compressibility.

Numerical investigation of gas-liquid two-phase flow in horizontal pipe with orifice plate

Gas-liquid two-phase flow in horizontal or vertical pipeline significantly impacts on the transportation process. In fact, in the pipeline for regulating the flow flux or pressure, orifice plate and other current limiting device are frequently encountered. The flow behaviors of two-phase flow thus become more complicated in the pipeline with orifice plate. In order to explore the characteristics of gas-liquid two-phase flow in the pipeline accompanied by orifice plate, the computational fluid dynamics (CFD) simulation with volume of fluid (VOF) method and SST k−ω eddy viscosity model were imposed to probe the transient two-phase flow in a horizontal pipeline. The reliability of the numerical method was verified by a case of annular multiphase flow in a pipeline. In our research, two transient simulations related to different liquid volume ratios were carried out to explore the developments of the flow regimes. In addition, fluctuations of the area-average fluid pressures acting on the orifice plate surfaces were also monitored. The frequency characteristics of pressure pulsations were extracted via non-uniform fast Fourier transform (NUFFT). The main results show that the jet could be produced after the liquid passes through the orifice plate, and the liquid volume ratio has significant effects on the gas-liquid two-phase flow behaviors, a higher ratio leads to a faster stable and fuller jet. The stability of jet could be reflected via the dimensionless velocity ratio. The gas-liquid two-phase flow in the pipe with orifice plate induces typical broadband excitation.

Estimation of solid concentration in solid–liquid two-phase flow in horizontal pipeline using inverse-problem approach

In this study, an inverse-problem method was applied to estimate the solid concentration in a solid–liquid two-phase flow. An algebraic slip mixture model was introduced to solve the forward problem of solid–liquid convective heat transfer. The time-average conservation equations of mass, momentum, energy, as well as the volume fraction equation were computed in a computational fluid dynamics (CFD) simulation. The solid concentration in the CFD model was controlled using an external program that included the inversion iteration, and an optimal estimation was performed via experimental measurements. Experiments using a fly-ash–water mixture and sand–water mixture with different solid concentrations in a horizontal pipeline were conducted to verify the accuracy of the inverse-problem method. The estimated results were rectified using a method based on the relationship between the estimated results and estimation error; consequently, the accuracy of the corrected inversion results improved significantly. After a verification through experiments, the inverse-problem method was concluded to be feasible for predicting the solid concentration, as the estimation error of the corrected results was within 7% for all experimental samples for a solid concentration of less than 50%. The inverse-problem method is expected to provide accurate predictions of the solid concentration in solid–liquid two-phase flow systems.

Experimental investigation of gas-brine liquid flow in horizontal pipeline

Pipelines that are transporting fluids of different salinity in different pressurized conditions are met with different behaviors of flow. Flow behavior of two-phase gas–liquid system in simulated horizontal pipeline conditions are investigated experimentally with three different brine salinity concentrations comparable to the reservoir fluid properties within the Malay Basin. A test facility in total length of 80-feet was designed and configured for data acquiring of flow regimes which were observed via a 1.5-in diameter and a 7.5-feet long transparent acrylic pipe. A flow regime map where the transition of flow pattern from stratified to intermittent to mixed is proposed as the superficial gas velocity and superficial liquid velocity increase at increasing brine concentration. There is a combination flow pattern presumed to be the combination of plug flow, slug flow and thin annular. When the brine salinity increases, the pressure drop of the system increases. The lowest pressure drop in the form of percentage for brine concentration of 1000, 15,000, and 30,000 ppm at brine superficial velocity of 3.0 m/s were 57.1, 50, and 42.9% respectively. Pressure drop experimental results from this study were compared with previous mathematical correlations. Results also indicate that water holdup increases when water input fraction increases.

Visualization and measurement of two-phase flows in horizontal pipelines

Understanding the dynamics of gas-liquid two-phase flows (G/L), is crucial to predict the transport efficiency of the mixture and the energy needed for pumping. In addition, many industrial processes are governed by momentum, heat, and mass transfer phenomena between the phases. Many examples can be found in the different stages of refinement up to the production of petroleum products, biomass transport, chemical reactors, nuclear waste decommissioning, pulp, and paper production, among many others. In this study, an experimental facility designed to analyze G/L mixture is presented and discussed. The experimental results are presented for gas-liquid flows in horizontal 30 mm ID pipelines. The mixture involved is composed of air and water. The superficial velocity of the liquid phase is in the range of 0–2 m/s and the gas phase from 0 to 2 m/s. The experimental data accounts for pressure loss, hold-up, superficial velocities, and flow regimes. A flow map is presented covering the specified ranges, and two-phase correlations for hold-up and frictional pressure loss are reported and compared with the available experimental data.

Comparative analysis between CFD model and DHLLDV model in fully-suspended slurry flow

The behavior of fully-suspended slurry flow in horizontal pipeline can be simulated through two very distinct models, the Computational Fluid Dynamics (CFD) model and the Delft Head Loss & Limit Deposit Velocity (DHLLDV) model. The predicted results from simulations are compared with a series of experiment data from the literature, involving the effects of different particles volume concentration (9–42%), particle size (90–440 μm), mixture velocity (1–9 m/s), and pipe diameter (51.5–263 mm) on hydraulic gradient and particles concentration distribution, and revealing excellent agreements between two model predictions and the experimental data. Both CFD and DHLLDV, however, still have some deviations in the near-wall concentration distribution as for larger particles. Though it is observed that the accuracy for CFD will decline when particle size increases and further research is needed for improving the accuracy of the models for the near-wall flow of larger particles, it can be concluded that both CFD model and DHLLDV model apply to calculations for fully-suspended flow.

Hydrodynamics and energy analysis of heavy crude oil transportation through horizontal pipelines using novel surfactant

Improvement of flow properties of crude oil through pipelines, the effect of temperature, diameter, water cut, and novel extracted surfactant on pressure drop, shear viscosity was studied along with energy analysis. The impact of diameter, temperature, and the addition of novel surfactant extracted from Madhuca longifolia (Mahua) on pressure drop, shear viscosity, pumping power saving and flow increment were investigated during heavy crude oil flow in horizontal pipelines. Minimum pressure drop was observed in 0.0508 m ID pipeline owing to the collective effect of temperature and 2000 ppm Mahua during the flow of 85% heavy crude oil+15% water. Shear viscosity reduced appreciably in 0.0381 m and 0.0508 m ID pipelines after addition of 2000 ppm Mahua at a temperature of 50 °C. Maximum power saving (130.8%) was achieved and maximum flow increment of 121.8% was accomplished after addition of 2000 ppm Mahua to 85% heavy oil and 15% water mixture during its transportation in 0.0508 m ID pipeline at a 50 °C and at the rate of 7.2 m3/hr. The natural surfactant is substantially efficient to decrease the pumping power consumption for heavy crude oil transportation. It was concluded that the extracted novel natural surfactant is very beneficial for being used as an emulsifier, viscosity reducer, flow improver and also an alternative for the commercial surfactant.