Flow Pressure Drop Research Articles

Three-dimensional numerical simulation of bubble dynamics and design optimization of microchannel in proton exchange membrane water electrolyzers

Proton exchange membrane (PEM) water electrolysis is considered as a promising and sustainable solution for energy storage and hydrogen production. The dynamic behaviors of gas bubble in microchannels have an important impact on the gas/liquid two-phase transport process during electrochemical reaction, consequently affect the performance and efficiency of PEM water electrolyzers. This paper aims to investigate and understand the phenomena of bubble detachment in microchannels during the operation of PEM water electrolyzers. The detachment process is captured in-situ/operando, and the four stages of bubble detachment are qualitatively analyzed. Three-dimensional numerical simulation is conducted to study the dynamics of bubble detachment in a Poiseuille flow of microchannel. A strategy of determine the critical flow velocity, pressure drop, and power consumption of bubble detachment in a microchannel with consideration of main forces acting on a bubble during detaching process is developed. The simulation results reveal that various factors, including the contact angle, microchannel size, and the shape and parameters of the upper wavy wall, significantly influence the behavior of bubble detachment and the associated power consumption. Based on these findings, a design strategy is proposed to enhance bubble detachment efficiency in microchannels. The suggested approach involves the implementation of a rectangular upper wavy wall with appropriate wavelength and amplitude, resulting in the lowest power consumption during the bubble detachment process. The present analysis results provide a better understanding of bubble dynamics behaviors and offer practical insights for optimizing the design of microchannels in PEM water electrolyzers.

Numerical study of transient flow characteristics of gas-liquid two-phase flow in inclined upward tube under periodic vibration

The transient flow characteristics of gas-liquid two-phase flow in inclined upward tubes exhibit a high degree of complexity. The tube vibration caused by multiple uncertain factors, such as seawater impacts or subsea earthquakes, poses more significant challenges for flow safety assurance. Thus, it becomes increasingly crucial to explore the transient flow characteristics of gas-liquid two-phase flow in inclined upward tubes under various vibration conditions. In this paper, the transient flow characteristics of gas-liquid two-phase flow in an inclined upward tube under different vibration conditions are numerically studied based on CFD dynamic mesh technique. In the current study, the studied parameters include vibration direction (heaving, transverse and coupling), vibration amplitudes (0.5D, 1.0D and 1.5D), and inlet velocity (jsg=0.5∼1.0m/s; jsl=0.1∼1.0m/s). The transient flow structure, cross-sectional void fraction and pressure drop are analyzed. The findings indicate that the transient flow structure of the slug flow demonstrates periodic variation characteristics under transverse and coupling vibrations, and the cross-sectional void fraction increase. For transition flow, the cross-sectional void fraction increases under transverse and coupling vibrations, while displays an increase initially and subsequently a decrease significant with an increase in the heaving vibration amplitude. Additionally, all considered vibration conditions intensify the pressure drop of the transition flow and decrease the cross-sectional void fraction of the turbulent flow.

A note on the determination of vortex parameters from combined seismic and barometric measurements

A theoretical model is proposed for determining the inclination (tilt) of the ground surface when a convective vortex, e.g., a dust devil, passes near a seismometer. For the Lorentzian profile of the pressure drop in the vortex flow, an expression for the ground tilt is obtained, which is valid for all distances of the closest approach of the vortex to the seismometer (miss distances). It is shown that, in this case, the combined seismic and meteorological measurements allow the elastic properties of the soil to be determined provided additional knowledge of the miss distance is available. On the contrary, if the elastic properties of the soil are known in advance, the combined seismic and meteorological measurements make it possible to determine all the main parameters of the vortex, as well as the closest approach distance of the vortex to the sensors. This is illustrated with examples of convective vortices recorded during the InSight mission to Mars.

COMPUTATION OF THREE-DIMENSIONAL BLOOD FLOW DEVELOPMENT IN A 180∘ CURVED TUBE GEOMETRY

Computational blood flow studies are providing an increasingly important complement to clinical experiments in 21st century biomedical engineering. Motivated by probing deeper into this topic, a theoretical and numerical study is presented of the flow induced by an impulsive acceleration to steady state hemodynamics in a curved tube which is investigated as a boundary layer developing with time from the curved entrance to a straight tube (blood vessel). The transient processes are simulated with a finite volume method solution of the Navier–Stokes equations. The rapid growth of the boundary layer with the core flow is captured in the curved entrance, along the tube to an axisymmetric flow in the downstream. Secondary flow patterns, centrifugal pressures and total head contours are correlated with longitudinal velocity distributions across various sections. It is observed that the entrance zone is controlled by uniform inlet velocity and centrifugal forces. The high pressure drop in the onset flow is associated with strong acceleration which is comparable to generating systolic pressures. The simulations further indicate that a sustained increment in volumetric flow rate is necessary to maintain the pressure wave in the aorta. Furthermore, the velocity distributions are shown to approach Hagen–Poiseuille flow in the downstream zone. The complex hemodynamic characteristics are visualized effectively with computational simulations and the study demonstrates the excellent ability of this approach in elaborating critical flow details in aortic hemodynamics.

P44: Toward 3D-Printed Microfluidic Artificial Lungs with Complex, Biomimetic Geometries

Purpose: Current hollow-fiber oxygenators used in Extracorporeal Membrane Oxygenation have suboptimal gas exchange performance and hemocompatibility. Microfluidic artificial lungs (µALs) promise smaller feature sizes, improving gas exchange efficiency, and biomimetic flow paths, improving blood compatibility. For the first time, we leverage the geometric freedom of 3D-printing technology to demonstrate µALs with truly 3D, biomimetic branching capillaries and gas-side designs to increase gas exchange surface area. Methods: Two µAL designs were generated in Solidworks and printed on an Asiga MAX X27 UV printer. The first was a “simple branching” µAL (Fig 1A) with quadfurcating, biomimetic branching for blood distribution. The second was a “hatched” µAL (Fig 1B) employing a gas phase with strategically placed supports to maximize gas exchange surface area while maintaining structural stability. These changes are only to the gas, and so the blood-phase is unchanged. Dyed water was used to visualize internal structures (Fig 1D). Geometric analysis and proven models were used to calculate theoretical shear rate and rated flow. Computational Fluid Dynamics (CFD) was used to visualize flow (Fig 1E,F). Experimental pressure drop vs water flow rates were measured (Fig 2). Results: Through geometric analysis (Table 1), branching distribution technique provides more uniform shear stress (0.95-1.34 dyn/cm2) compared to a non-branching “open-plenum” control (0.09-1.27 dyn/cm2). The hatched µAL has a 3.18 mL/min rated flow, 1.7x greater than the 1.84 mL/min rated flow of the non-hatched branching µAL. As a result of the higher rated flow, it also has higher theoretical shear of 1.64-2.31 dyn/cm2 (at rated flow) despite identical blood-side geometry. The branching lung demonstrated a pressure drop up to 12 mmHg at flows up to 5 mL/min (Fig 2). These are significantly larger than analytically predicted values (extrapolated 7 mmHg vs 0.233 mmHg at 3.2 mL/min), prompting investigation into resolution of internal capillaries and effects of surface roughness on pressure drop. Conclusion: We have demonstrated the first 3D-printed branching biomimetic µAL formed from a gas permeable material, with gas-side geometries to improve gas exchange efficiency. These geometries are expected to translate to greater blood flows enabling creation of future animal and human-scale µALs. Table 1. Theoretical calculations. All uALs have 256 8.5mm long 216x324 µm blood and gas channels, with 54 µm-thick membranes. They differ in their effective gas exchange area, and blood distribution method, resulting in differing rated flows, shears, and pressure drops. The Branching uAL employs a branching distribution, resulting in a much tighter shear stress range. The GasHatch uAL employs both a branching distribution, and a blood-gas geometric-synchronization, with 100% rather than 58% of the gas-exchange capillary face being used for gas exchange. Values for a theoretical “control” lung (not fabricated; contains an open plenum/ non-branching distribution region) are displayed for comparison. Flow velocity and shear stresses are calculated separately for capillary and distribution areas.Figure 1. Blood flows are indicated using red arrows, and gas flows are indicated using blue arrows. (A) Design of simple (non-hatched) branched μAL. (B) Close-up of the hatched μAL capillaries and gas channels, showing how gas-side supports are only in regions not adjacent to capillaries and therefore not reducing gas exchange surface area. (C) Hatched μAL with the gas phase filled with blue dye for visualization. (D) Non-hatched branching μAL with blood phase filled with blue dye, and gas phase filled with red dye. (E) CFD visualization of flow velocities in the branching blood distribution network; (F) CFD analysis of pressure drop in the biomimetic blood distribution channels.Figure 2. Pressure drop of branching µALs (water; n=3)

Impedance models for single and two degree of freedom linings with an improved data base and local non-linearity

Previously developed predictive models for impedance of single-degree-of-freedom and two-degree-of-freedom acoustic linings driven by a broad band acoustic source are reexamined. Two issues are addressed, the first being improvement of the conventional perforate face sheet impedance model. Data correlations based on flow bench measurements of steady flow pressure drop are reevaluated with emphasis on low flow velocity to improve the consistency of the prediction of linear resistance. In addition, for two-degree-of-freedom linings, face sheet mass reactance is modified to account for the presence of the septum. The second issue addresses the implication that for a non-linear lining, with impedance a function of the local sound pressure level, the installed performance of the lining depends on the local impedance, as opposed to impedance based on the source sound pressure level. This is investigated in the benchmarking of the impedance models by comparison of the acoustic transfer function predicted by a propagation code with the imbedded impedance model and transfer function measurements made in a grazing flow duct test facility. The propagation code is extended to make the non-linear behavior of the lining model dependent on the local acoustic spectrum, introducing an additional level of non-linearity and an iterative application of the propagation code. A principal conclusion is that with no grazing flow both the lining model and grazing flow duct transfer function measurements show a significant effect of local variation of the acoustic spectrum. With increasing grazing flow Mach number, this effect is reduced and effectively disappears at the highest Mach number. With increasing grazing flow Mach number the grazing flow contribution to face sheet resistance dominates and tends to mask the non-linear behavior of the component of resistance not related to grazing flow.

Study on anode single-phase flow pressure drop law of proton exchange membrane fuel cell

This article briefly describes the research status of water flooding and pressure drop (PD) of the fuel cell. Then, a mathematical model of the single-phase flow PD of the fuel cell anode is established using hydrodynamics theory and referring to existing research. Then, the three-dimensional fuel cell model is established with Gambit software, and the grid is divided. Then, the numerical simulation of the single-phase flow of the fuel cell is carried out with Fluent software. Through the analysis of the simulation data, the relationship between the fuel cell anode pressure drops and some main influencing factors under steady-state conditions is explored, and the fuel cell anode’s single-phase flow pressure drop model is preliminarily verified. Anodes are highly sensitive to water flooding. The study of the single-phase flow PD law has a good contrast effect on the abnormal pressure drop during water flooding of fuel cells, which can be used to diagnose water flooding.

Global sensitivity analysis for phosphate slurry flow in pipelines using generalized polynomial chaos

Slurry transportation via pipelines has garnered growing attention across various industries worldwide, thanks to its efficiency and environmental friendliness. It has emerged as a vital tool for conveying significant volumes of raw phosphate material from extraction points to industrial plants, where it is processed into fertilizers. Yet, optimal and secure pipeline operations necessitate the careful calibration of several physical parameters and their interplay to minimize energy losses. A thorough exploration of the flow pressure drop and the various factors that influence it constitutes a crucial step in attaining this goal. The computational fluid dynamics techniques required to simulate three-dimensional slurry pipe flows pose formidable challenges, primarily due to their high computational costs. Furthermore, numerical solutions for slurry flows are frequently subject to uncertainties arising from the initial and boundary conditions in the mathematical models employed. In this study, we propose the use of polynomial chaos expansions to estimate the uncertainty inherent in the desired slurry flow and perform a sensitivity analysis of flow energy efficiency. In this framework, five parameters are considered as random variables with a given probability distribution over a prescribed range of investigation. The uncertainty is then propagated through the two-phase flow model to statistically quantify their effect on the results. Our findings reveal that variations in slurry velocity and particle size play a pivotal role in determining energy efficiency. Therefore, controlling these factors represents a critical step in ensuring the efficient and safe transportation of slurry through pipelines.

Overview of Oil-water Two-phase Flow Pressure Drop Theory

This is a review of the existing pressure drop theories for dispersed and annular flow in oil and water phases in straight wells is presented. The flow classification criteria, pressure drop calculation methods are outlined. For the dispersed flow, the homogeneous flow model and the two-fluid model are introduced. The key to the pressure drop of the homogeneous flow is the calculation of the frictional resistance, and the two-fluid model focuses on the drag force between the two phases. And for the core-annular flow, the two-fluid model is used to focus on the interference between the two-phase interface.

Experimental viscosity monitoring in complex pipe systems for flows of drilling muds based on the energy dissipation rate

This study aimed to measure the viscosity of non-Newtonian fluids (xanthan gum solution and drilling muds) in-situ during complex pipe flows using pressure drop and flow rate data without sampling. This method of viscometry can be applied to various inelastic non-Newtonian fluids and pipe systems of general geometries, including shear-thinning fluids (such as xanthan gum) and viscoplastic fluids with yield stress (drilling mud), as long as the flow rate and pressure drop within the system can be measured in-situ. The method employs two flow numbers (energy dissipation rate coefficient and effective shear rate coefficient) that are mainly determined by the flow geometry, nearly independent of the rheological behavior of a fluid. The representative effective shear rate for a given system is determined by the effective shear rate coefficient and flow rate; and the relationship between effective viscosity and material viscosity was found to be identical. The method was validated with three different non-Newtonian fluids in three different lab-scale complex pipe systems, including a straight circular pipe with connectors, a pipe system with an intermediate branch, and a 3D pipe system with height and slope variations. The accuracy assessment of viscosity measurement and pressure drop prediction showed no more than an 18.7% error in all the cases. The in-situ viscosity measurement method presented in this study can be used for process monitoring and process quantification of non-Newtonian fluid flows in various types of pipe flows used in industrial processes.

Thermohydraulic performance analysis of HCPV/T systems with impinging confined jets and symmetric multi-junction PV modules

BackgroundThis study investigates the cooling of four high-concentrator photovoltaic/thermal systems with panels that have two lines of symmetry. Liquid-submerged jet impingement is used to cool four symmetric multi-junction modules. The performance of four circular impinging jets with nozzle diameters of 1 mm under each cell is compared with that of a circular impinging jet with a nozzle diameter of 2.5 mm at the center of the heat sink. The solar radiation of 1000 suns is considered in the simulations. The flow regimes are laminar, and the results are obtained for mass flow rates within the range of 100-200 gr/min. MethodsSince the geometry of the problem is complex, no analytical solution for temperature distribution is available. Also, there are no suitable tools for measuring the temperature distribution in the flow and solid walls at the desired scales. Therefore, a three-dimensional simulation using the finite volume method by Fluent was used in this research. To apply the relationship between the cell temperature and the electrical efficiency in each iteration and achieve the new cell temperature, a User-defined Function (UDF) has been developed. FindingsThe cell arrangement on panels in both jet configurations (four nozzles and a single nozzle) gives average cell temperature differences that are less than 1°C. The single nozzle system reduces the flow pressure drop while it increases the maximum temperature of the germanium layer by 8°C and makes its temperature more non-uniform than the four nozzles system with the same configuration. The non-uniformity in the surface temperature of the germanium layer in all the models varies between 10°C and 20°C which indicates the necessity of combining this technique with another method to cool such a system.

Numerical and experimental evaluation of the configurational effects on the thermohydraulics of an Ag-MgO/water hybrid nanofluid flow in a circular heatsink with optimization energy efficiency

BackgroundIn this paper, the thermal performance of a novel circular mini heatsink (MHS) is investigated experimentally and numerically. An Ag-MgO/water hybrid nanofluid (NF) flow enters the center of a MHS, consisting of different layers and exits the system from the circumference. The circular heatsink includes four different internal configurations wherein the number of holes on the walls of each layer is different. MethodsAn experimental setup is developed to measure the flow and heat sink temperatures as well as the flow pressure drop (PDP) under varying operational conditions. Heat transfer processes in the heatsink are also simulated numerically using a finite element technique. Significant findingsThe numerical results are then validated against the obtained experimental data, and the outcomes are analyzed by considering thermohydraulics and economic criteria. An increment in the volume percentage of nanoparticles from 0 to 2% in heatsink models 1 to 4 enhances the pump power by 15.9%, 16.6%, 19%, and 22.5%, respectively. The enhancement in Re reduces the maximum temperature by 7.6% and the average temperature by 24.41° (7.2%). When the volume percentage of nanoparticles is 2%, the FOM is increased by 5.2% with Re. As the volume percentage of nanoparticles changes from 2 to 1%, the FOM is decreased by 14.3%.

Enhancing the dynamic performance of proton exchange membrane fuel cells through two-phase flow experimental investigation

Efficient water transfer is crucial for enhancing the rapid response and durability of proton exchange membrane fuel cells (PEMFCs). In this paper, ex situ observation experiments and in situ dynamic performance tests of fuel cells are conducted and correlated with each other by two-phase flow pressure drop. The experimental results show that slug flow within the cathode gas flow channels (GFCs) is unfavorable to mass transfer and results in loading failure under high current densities, as identified in Design Failure Mode and Effects Analysis (DFMEA). However, slug flow in GFCs of PEMFCs can be converted into film flow by reducing the hydraulic diameter of GFC, increasing the air stoichiometry ratio, and extending the loading resistance time to an appropriate value. This facilitates a successful and efficient load change process of PEMFCs under high current densities. This study provides a methodology, combines ex situ observation and in situ evaluations, identifying potential risks, which can shed light on improving the dynamic performance and development process of PEMFCs.

Review of Flow Field Designs for Polymer Electrolyte Membrane Fuel Cells

The performance of a polymer electrolyte membrane fuel cell (PEMFC) closely depends on internal reactant diffusion and liquid water removal. As one of the key components of PEMFCs, bipolar plates (BPs) provide paths for reactant diffusion and product transport. Therefore, to achieve high fuel cell performance, one key issue is designing BPs with a reasonable flow field. This paper provides a comprehensive review of various modifications of the conventional parallel flow field, interdigitated flow field, and serpentine flow field to improve fuel cells’ overall performance. The main focuses for modifications of conventional flow fields are flow field shape, length, aspect ratio, baffle, trap, auxiliary inlet, and channels, as well as channel numbers. These modifications can partly enhance reactant diffusion and product transport while maintaining an acceptable flow pressure drop. This review also covers the detailed structural description of the newly developed flow fields, including the 3D flow field, metal flow field, and bionic flow field. Moreover, the effects of these flow field designs on the internal physical quantity transport and distribution, as well as the fuel cells’ overall performance, are investigated. This review describes state-of-the-art flow field design, identifies the key research gaps, and provides references and guidance for the design of high-performance flow fields for PEMFCs in the future.

Evaluation of prediction models on frictional pressure drop for condensation flow in horizontal circular tubes

ABSTRACT There are numerous correlations available for predicting frictional pressure drop of condensing flow in horizontal tubes. It is necessary to evaluate and analyze the prediction accuracy and applicability of existing correlations. In order to explore the versatility of frictional pressure drop correlations for condensation flow with different working fluids, four existing models are investigated: phase-separation conversion model, full-phase flow model, two-phase multiplier flow model, and homogeneous flow model. Combined with five different working fluids (R170, R12, R600a, R22, R1234yf), 402 groups of experimental data on frictional pressure drop for condensation flow in horizontal circular tubes are considered with respect to flow pattern. The prediction results based on each correlation are compared and analyzed. Mean absolute relative deviation (MARD) and mean relative deviation (MRD) are selected as indicators to evaluate each correlation. The results showed that the versatility of the existing correlations needs improvement. The prediction accuracy of frictional pressure drop for condensation flow can be improved by selecting different correlations for different flow patterns. The phase-separation conversion model has a good prediction effect and a wide application scope in annular flow. The maximum MARD is 15.85%, and the maximum MRD is 8.72%. 93.08% of the data predicted deviation is less than 30%. This study will provide some constructive instructions to predict frictional pressure drop of condensation flow in horizontal circular tubes for designing heat exchangers.

Effects of Large Particles in Pipe Flow at Low and Moderate Reynolds Numbers

AbstractThe presence of solid particles in a Newtonian liquid flow will affect the properties of the flow. For small particles these effects are fairly well understood and models, for example for the pressure drop in particle laden pipe flows have been present for a long time. However, the behavior of liquids laden with large particles are less well understood. In the present study, large particles of spherical shape are considered. By large is here meant particles that are of the same size as the large scale length scales of the flow and larger. The effect of particles volume fraction on parameters such as pressure drop and velocity distribution in the pipe flow is investigated. The sizes of the particles are 17 % and 40 % of the pipe diameter and the volume fraction is varied between 5 % and 20 %.

Numerical Investigation on Flow Pattern, Heat Transfer and Pressure Drop Characteristics of Flow Boiling with Discrete Heat Sources

Heat dissipation and temperature uniformity are one of the key technologies for electronic equipment. With the rapid growth of computing demand and the wide application of multichip devices, heat sources are distributed discretely in space. Therefore, the flow boiling in the mini-channel with two discrete heat sources is investigated in this study. The effects of heat source distribution, inlet fluid temperature and channel diameter on flow pattern, heat transfer and pressure drop are discussed in detail. The results show that intermittent flow tends to form around discrete heat sources, especially near the heat source which is far from the channel inlet. Moreover, the distance between discrete heat sources shouldn’t be too close to avoid heat concentration, nor too far to make full use of latent heat. When the distance between two heat sources is 70 mm, the temperature distribution is appropriate, and the heat dissipation is the best in this study. For the discrete heat source far from the inlet, the heat transfer coefficient increases significantly when the inlet fluid temperature increases due to the preheating of another heat source.

Experimental study of swirling flow pneumatic liquid-carrying characteristics in the vortex tool inserted tube under liquid loading conditions

Liquid unloading by vortex tool is one of the most important applications of swirling flow pneumatic conveying. However, due to swirl decay, the evolution of gas–liquid flow patterns and the dynamic characteristics of pressure drop downstream of the vortex tool are much more complex than those in non-swirling flow. In this study, the gas–liquid flow patterns and pressure drop inside the vortex tool inserted tube (ID = 60 mm) under liquid loading conditions were experimentally studied and compared with those of the plain tube. With the superficial gas velocities ranging from 0.5 to 6.0 m/s and superficial liquid velocities of 0.01, 0.02, and 0.04 m/s, the effects of the structural parameters and stages of vortex tools on the pressure drop were discussed. The experimental results reveal that three distinct swirling flow patterns can be identified downstream of the vortex tool, namely swirling gas column flow, swirling churn flow and swirling annular flow. The insertion of vortex tool facilitates an earlier transition of the churn flow to the annular flow, and the induced swirling flow can restrain the liquid from falling back. The helix angle of the corkscrew deflector has a more significant effect on the pressure drop than its length. By reducing the helix angle from 54° to 45°, the total pressure drop and downstream pressure gradient are significantly decreased, even lower than those of the plain tube. But the series combination of 54° and 45° vortex tools results in a significant increase in the downstream pressure gradient. Additionally, at low gas flow rate, negative frictional pressure drop occurs in both plain tube and vortex tool inserted tube. Hence, the new friction factor correlations were established respectively for the positive and negative friction regions in the cases of the tube with and without vortex tool, and most of the frictional pressure gradient predictions are within an error band less than 20%.

Improving production and prediction of the flow regimes, pressure drop, and void fraction in the perforated horizontal wellbore

This study aimed to investigate how oil production could be improved by experimenting with different distribution methods across multiple profiles. The authors tested five different profiles that included uniform radial airflow (explained in profile 1) and variable radial airflow (explained in profiles 2, 3, 4 and 5) in a perforated horizontal wellbore. In addition, the study predicted the behavior of total pressure drop, superficial mixture velocity and void fraction encountered in different flow patterns (bubble, slug, stratum and stratum wave flow). Flow patterns were predicted using ANSYS Fluent R3 with a borehole length of 3 m and an ID of 0.0381 m. This was designed with 12 perforations opening vertically at the wellbore with a phase angle of 180 and a perforation density of 4 shots per foot to simulate the complex flow in a horizontal wellbore. In the perforated section, there was a fluctuation in the behavior of the parameters, while in the non-perforated section, the behavior remained constant. The behavior of the total pressure drop, the superficial velocity mixtures and the void fraction were also reasonably uniform in profile 1 in the perforated section.In contrast, they were irregular in the other profiles. In profiles 2, 3, 4 and 5, the behavior of the mixture superficial velocity and void fraction was inverse to the total pressure drop. Note that all theoretically calculated pressure drop modes increased as the Reynolds number of the mixture increased. The liquid and air product increased with increasing Reynolds number of mixture flow in the profiles. In contrast, in profile 1, lower production was obtained through all flow patterns due to the influence of the mixture pressure and the friction factor. The Vogels method was used to calculate maximum production from the horizontal wellbore. The convergence between experimental and numerical results was good during all cases (flow patterns), with some difference in the static pressure drop behaviuor occurring during flow patterns (bubble, dispersed bubble and slug flow).

Pressure drop of turbulent flow across pipe bends

Pressure drop of turbulent flow across 90[Formula: see text] round bends with 10mm inside diameter investigated by employing the shear stress transport [Formula: see text] turbulent model for numerous curvature ratios and flow conditions. A total of 10 flow velocities varied from 1 to 10 m/s and 17 curvature radii between 5 and 300 mm were examined. Velocity profiles were evaluated at eight locations to examine the entrance effect. The simulation results were verified by comparing the evaluated Darcy friction factor with a well-known published correlation. The obtained results of bend pressure drop demonstrate the domination of the curvature ratio effect on the pressure drop over the influence of other factors. The computed pressure loss across the bend in terms of pressure loss coefficient [Formula: see text] and equivalent length to diameter ratio [Formula: see text] shows a good agreement with various published data in the literature with [Formula: see text] maximum average error. The coincidence between the results and the published data verifies the accuracy of the employed model to evaluate the pressure drop of turbulent flow throughout 90[Formula: see text] bends for the applied boundary conditions.