Flow Loop Research Articles

Myocardial work and energy loss of left ventricle obtained by pressure-strain loop and vector flow mapping: a new perspective on idiopathic left bundle branch block

To date, no research has been conducted on the electrical activity and mechanical dyssynchrony of idiopathic left bundle branch block (iLBBB) with normal left ventricular ejection fraction (LVEF). This study sought to assess the left ventricular summation of energy loss (EL-SUM) and average energy loss (EL-AVE) using vector flow mapping as well as myocardial work using pressure-strain loop (PSL) in patients with iLBBB and normal LVEF. We prospectively recruited 35 patients with iLBBB and 35 control participants with normal LVEF. Echocardiography was performed. Conventional echocardiographic parameters, myocardial work, and energy loss (i.e., the EL-SUM and EL-AVE) were calculated. In relation to global myocardial work, compared to the control participants, the iLBBB patients showed decreased global longitudinal strain (GLS; -15.32%±2.58% vs. -18.27%±2.12%; P=0.001), a decreased global work index (GWI; 1,428.24±338.18 vs. 1,964.87±264.16 mmHg%; P<0.001), decreased global work efficiency (GWE) (84.48±5.19 vs. 91.73±5.31 mmHg%; P<0.001), and significantly increased global waste work (GWW; 341.60±132.62 vs. 161.80±106.81 mmHg%; P<0.001). In relation to the regional index, the iLBBB patients had a significantly reduced basal anteroseptal segment (879.15±370.50 vs. 1,746.38±154.44 mmHg%; P<0.001), basal inferoseptal segment (1,111.42±389.04 vs. 1,677.25±223.10 mmHg%; P<0.001), mid-anteroseptal segment (1,097.54±394.83 vs. 1,815.06±291.22 mmHg%; P<0.001), mid-inferoseptal segment (1,012.54±353.33 vs. 1,880.88±254.39 mmHg%; P<0.001), apical anterior segment (1,592.42±366.64 vs. 1,910.00±170.27 mmHg%; P=0.001), apical lateral segment (1,481.62±342.95 vs. 1,817.19±227.55 mmHg%; P=0.001), apical septal segment (1,437.65±428.22 vs. 1,852.25±275.19 mmHg%; P=0.001), and apex (1,542.62±342.89 vs. 1,907.06±197.94 mmHg%; P<0.001). The iLBBB patients had increased EL-AVE and EL-SUM during the late-diastole, isovolumic-systole, and rapid-ejection periods [EL-AVE in T2: 28.3 (8.7, 49.0) vs. 6.8 (5.4, 9.4) J/(s·m3); P=0.029]; [EL-AVE in T3: 24.7 (13.0, 46.8) vs. 7.2 (5.4, 10.8) J/(s·m3), P<0.001]; [EL-AVE in T4: 18.3 (12.0, 27.6) vs. 7.7 (4.1, 11.6) J/(s·m3), P=0.002]; [EL-SUM in T2: 8.3 (2.2, 14.5) vs. 2.1 (1.6, 3.2) J/(s·m), P=0.049]; [EL-SUM in T3: 7.6 (4.0, 14.5) vs. 2.2 (1.7, 3.3) J/(s·m), P<0.001]; [EL-SUM in T4: 5.3 (3.6, 9.7) vs. 2.2 (1.4, 3.0) J/(s·m), P=0.004]. The GWI and GWE were reduced in patients with iLBBB, especially in the septum and apex. The EL-SUM and EL-AVE were higher in patients with iLBBB during the late-diastole, isovolumic-systole, and rapid-ejection periods. EL and PSL reflect the LV hemodynamics of patients with iLBBB.

A proposed integrated model to assess product recovery pathways: The case of solar photovoltaics

A Circular Economy (CE) is facilitated by the closing of material flow loops. This requires the development of complex collection, sorting, and product recovery mechanisms. Besides infrastructural challenges, product recovery is further complicated by the manufacture and consumption of increasingly complex multi-component and multi-material products whose design often limits efficient disassembly at the end of product life. The lack of information on how to treat end of use (EoU) products and the associated costs further inhibits recovery-related decision-making. Thus, the default EoU treatment is often simply landfilling and/or incineration resulting in the loss of valuable resources. In addition, resulting environmental degradation may be avoided when other product recovery strategies such as recycling, remanufacturing and direct reuse are applied. This paper proposes a system dynamics tool inspired by the materials recovery hierarchy to understand the sustainability impacts of EoU recovery. The model evaluates environmental trade-offs for alternate product recovery strategies prioritizing the recovery of EoU products, sub-assemblies, components, and materials over more destructive options of landfilling and incineration. A case study centered around EoU solar photovoltaic (PV) panels is used to validate the model.

ONE-DIMENSIONAL MIXTURE MODEL CODE FOR THE MODELING OF TWO-PHASE FLOW THERMOSIPHON

The numerous coupled physical phenomena involved in natural circulation two-phase flow loops make their analytical or numerical modelization difficult. A 1D mixture model code has been developed for the sizing of semi-closed thermosiphon loops. The results of the code have been compared to existing experimental data of several two-phase flow thermosiphons. A reasonable agreement was found between the experimental and computed mass fluxes. Additionally, a sensitivity analysis was conducted on the pipe diameter, the imposed pressure, and the position of the condenser. The model was finally used to size an experimental thermosiphon loop.

A 3-D Printed Optically Clear Rigid Diseased Carotid Bifurcation Arterial Mock Vessel Model for Particle Image Velocimetry Analysis in Pulsatile Flow

Abstract In recent years, blood flow analyses of diseased arterial mock vessels using particle image velocimetry (PIV) have been hampered by the inability to fabricate optically clear anatomical vessel models that realistically replicate the complex morphology of arterial vessels and provide highly resolved flow images of flow tracer particles. The aim of this paper is to introduce a novel approach for producing optically clear 3-D printed rigid anatomical arterial vessel models that are suitable for PIV analysis using a common 3-D inkjet printing process (using a Formlabs Form 2 3-D printer) and stock clear resin (RS-F2-GPCL-04). By matching the index of refraction (IOR) of the working fluid to the stock clear resin material, and by printing the part in a 45-deg print orientation, a clear anatomical model that allows clear visualization of flow tracer particles can be produced which yields highly resolved flow images for PIV analyses. However, a 45-deg print orientation increases the need for post-processing due to an increased amount of printed support material. During post-processing, the part must be wet sanded in several steps and surface finished with Novus Plastic Polish 3 Step System to achieve the final surface finish needed to yield high-resolution flow images. The mock arterial vessel model produced in this work is a 3-D printed diseased carotid bifurcation artery developed from CTA scan data. A PIV analysis was conducted on the developed mock arterial vessel model installed in a complex transient flow loop to assess the flow profiles within the model and the clarity of the model. A computational fluid dynamics (CFD) simulation was conducted on the same carotid bifurcation arterial geometry, and the results were used as a benchmark comparison for PIV results. The results obtained in this work show excellent promise for using the developed approach for developing 3-D printed anatomical vessel models for experimental PIV analyses. The fabrication methodology of the clear anatomical models, PIV results, and CFD results is described in detail.

Influence of geometrical and operational parameters on the performance of natural circulation looped parabolic trough collector

Natural circulation loop of a larger diameter is analysed analytically in the present study intending parabolic trough application. 1-D analytical model is developed and validated with 3-D numerical model. SolTrace® is used to find the heat flux distribution over the receiver. The validated analytical model is used to study the effect of geometric and operating parameters on the flow rate and bulk temperature of the heat transfer fluid under different solar irradiances and the optimised model is defined. To enhance the loop performance further, Al2O3 nanofluid at different volume fractions are incorporated, which resulted in 55% improvement in the loop flow rate compared to the model with base fluid. Finally, the use of single-phase natural circulation systems can be a replacement to the existing conventional systems and provide sustainability.

The Influence of Plant Extract on the Phase Equilibrium of Structure I Gas Hydrate in a Simulated Offshore Environment

Gas hydrate inhibitors, especially those used in offshore environments, are chemicals. These chemicals are synthetic in nature and pose both technical and environmental risks. This study emphasizes the influence of a Plant Extract (PE) on the phase behavior and equilibrium of structure I (SI) gas hydrate and its inhibition efficiency. The PE was screened using a mini flow loop. From the pressure-temperature phase diagram, the various weight percentages of the PE were able to disrupt the thermodynamic equilibrium conditions of the water and gas molecules to lower temperatures and increase pressures, which caused a shift in the equilibrium curve to an unstable hydrate formation zone. The pressure versus time plot as well as the inhibition efficiency plots for the PE and Mono Ethylene Glycol (MEG) were evaluated. Overall, the inhibition efficiency of the PE was higher than that of MEG for 1 wt% (60.53%) and 2 wt% (55.26%) but had the same efficiency at 3 wt% (73.68%). The PE at 1 wt% had the greatest inhibition effect and adjudged the optimum weight percent with a well-regulated phase equilibrium curve. This shows that PE is a better gas hydrate inhibitor than MEG, which is toxic to both human and aquatic life; therefore, it is recommended for field trials.

Pulsatile gas-liquid flow resembling Decompression Sickness: Computational Fluid Dynamics simulation and experimental validation.

This work performs two-dimensional Computational Fluid Dynamics (CFD) simulations of pulsatile bubbly flow in a column resembling the flow inside human vena cava during Decompression Sickness (DCS), aiming to illustrate the effect of certain parameters in bubbly blood flow and so facilitate the design of the: a) corresponding in-vitro bubbly flow experiments under pulsatile flow conditions inside a flow loop and b) in-vivo trials on swines for assessing a novel electrical impedance spectroscopy technique on the detection of bubbles (as those found during DCS) in their bloodstream. The commercially available ANSYS 2019-R3 CFD code was employed to simulate the pulsatile bubbly flow that resembled DCS. Simulations were validated against experiments conducted in a vertical co-current upward pulsatile bubbly flow provided by a flow loop equipped with electrical, optical and pressure diagnostics. CFD simulations under pulsatile conditions were initially validated by oscillatory in-vitro bubbly flow experiments. Then, the influence of pulsation parameters on void fraction, α, and flow velocity, U, profiles was computationally investigated. Intense periodic fluctuations of void fraction were observed along the column and their intensity increases with pulsation amplitude. Moreover, U and α radial profiles were uniform for bubbles 30 μm but showed a core-peaking profile for bubbles 300 μm. CFD simulations of pulsatile bubbly flow resembling DCS provided unconventional information about the influence of different-sized sub-millimetre bubbles on the flow velocity and void fraction profiles, which are expected to improve the design of in-vitro and in-vivo trials for the detection of bubbles such as those found in DCS.

Erosion-Corrosion of Gathering Pipeline Steel in Oil-Water-Sand Multiphase Flow

This work studies a series of factors influencing erosion-corrosion in oilfield gathering pipelines steel using the home-made testing pipe flow loop. Results showed that steel was corroded in oil-water flow. The corrosion rate increased with the flow velocity on the whole, and the addition of solid particles would intensify the localized corrosion. For the erosion-corrosion test added with 2 wt% quartz sand at the velocity of 2 m/s, the portion of pure corrosion and pure erosion accounted for 47.50% and 70.83%, respectively. The erosion-enhanced corrosion was 16.67% of the total weight loss, while the corrosion inhibiting the damage from erosion accounted for 35.00%, so negative synergistic effects appeared in the oil-water-sand multiphase flow conditions.

Experimental and numerical investigation of an innovative non-combustion impulse gas turbine for micro-scale electricity generation

Fulfilling electricity demand in a remote platform has been a great challenge for oil and gas industry. With only pressurized gas line available, the choice of technology that can be implemented is limited; one of it is impulse gas turbine. At the moment, no studies investigating the performance of a compact impulse gas turbine which utilizes pressurized gas line has been reported, hindering the wide adoption of this technology. This study is therefore conducted with the main objective to investigate the performance of small scale impulse gas turbine for electricity generation by using computational fluid dynamics (CFD) approach in tandem with experimental validation. Three-dimensional computational model for the turbine is developed. Concurrently, an experimental set-up, consisting of micro impulse gas turbine, electric generator, flow loop and control system, is prepared to validate the model prediction. The effect of several key parameters, such as working fluid, rotational speed, mass flow rate and input pressure are evaluated to obtain operating envelope of the turbine. Overall, good agreement is achieved between numerical model prediction and experimental measured value. On the effect of working fluid, the results indicate that the impulse gas turbine driven by natural gas at 69 bar produce maximum power output of 1743.81 W at lower speed of 4500 RPM while maximum power of 1084.04 W can be achieved when driven by compressed air at 19 bar at rotational speed of 7000 RPM. In addition, a complete operating envelope for the turbine operating with either compressed air or natural gas has been developed. Furthermore, the effect of distance between nozzle outlet and turbine blade has been evaluated for which the optimum distance within studied range is obtained: 49.62 mm for one with compressed air and 54.62 mm for one with natural gas. The result from this study is expected to serve as a guideline in designing micro impulse gas turbine for electricity generation especially for remote offshore platform.

Numerical simulation of operational transients in sodium-cooled fast reactors

Reactor startup and shutdown are planned plant transients that are expected numerous times in the life of a nuclear reactor. These transients are desired to be carried out quickly for economic benefits and at the same time safely, which demands slower execution. The various plant design and safety constraints to be met during the execution of these transients in a typical medium-sized sodium-cooled fast reactor (SFR) were discussed. Operational procedures for the execution of these transients were reported in detail. A “wait and raise” mode for the startup and a “wait and lower” mode for the shutdown were adopted. During these procedures, primary and secondary loop flow rates were decided to be maintained at a nominal 100 % flow to avoid thermal stratification issues in sodium pools. Feedwater flow will be controlled based on sodium temperature at the steam generator (SG) outlet. The dynamics analysis for a reference SFR design was then carried out using plant dynamics code DYANA-P. The modeling details and approximations for simulating the startup and shutdown transients using the DYANA-P code were discussed. Two operational parameters, namely, control rod movement distance and waiting time between control rod movements, were optimized as 2.3 mm and 2.75 min, respectively, for the reactor's beginning of equilibrium cycle (BOEC) core configuration. The startup and shutdown durations were both estimated as ∼20.5 h each. The hot pool temperature change rate was estimated as ∼19 °C/h, which is less than the allowable limit of 20 °C/h. The SCRAM parameters, namely, reactor period and reactivity, were less than their alarm limits, thus, not interfering with the planned operations. The design and operational constraints of various plant systems were also satisfied. Parametric studies were also carried out for a few parameters: the fuel-clad interaction and the core burnup conditions. The assumptions of fuel being stuck to the clad (in feedback reactivity calculation) and the BOEC core configuration gives a higher power raising rate for a given control rod stroke and waiting time.

Experimental and numerical investigation of erosion in plugged tees for liquid-solid flow

Sand particle erosion is a prevalent issue that cannot be ignored in oil field development and may lead to leakage accidents. Consequently, it is significant to investigate and quantify erosion in pipelines. In this study, a flow loop is utilized to study the erosion of plugged tees in liquid‒solid flow. Then, computational fluid dynamics (CFD) software ANSYS Fluent is used to develop an erosion prediction numerical model, and the numerical erosion profile is validated with the experiments. Through particle trajectory analysis, three representative particle movement paths are selected, which provides a deeper understanding of erosion generation. Additionally, the erosion damage mechanism is analyzed through the surface morphology of the samples and particle impact behavior. The findings reveal that particles can follow the secondary flow to impact the inside of the downstream pipe under the experimental flow conditions. As the particle size or liquid velocity increases, the particles begin to erode the outside of the pipe under the action of inertial force. Due to the low-angle impact of the particles, the corresponding erosion damage mechanism is micro-cutting.

Study on anti-disturbance capacity of LBE cooled double loop natural circulation system under asymmetric conditions

Heat exchangers in natural circulation LBE-cooled fast reactors are used in harsh conditions such as extreme temperatures, significant pressure differences, high density, and corrosive environments. Therefore, heat transfer tube rupture and flow blockage accidents are common and result in an asymmetric heat load or asymmetric resistance thereby significantly impacting the safe and stable operation of the reactor.In this study, SNCLFR-10 has been used as the reference reactor and FLUENT simulation is used to establish the LBE-cooled dual-loop natural circulation system. Consequently, a theoretical solution of the natural circulation flow of a dual-loop system (TSNCD) is deduced using dimensionless analysis.The TSNCD theoretical solution is verified by using a dual-loop natural circulation system established via FLUENT simulation. Subsequently disturbance characteristics of the natural circulation system under different heat load differences or resistance differences are analyzed. The characteristic parameters representing the anti-disturbance capacity of natural circulation are determined using fitting approximation, and the best anti-disturbance interval is obtained.The results show that the TSNCD theoretical calculation formula of dual-loop natural circulation flow is extremely reliable, and the error between the calculations and the FLUENT simulation result is less than 5 %.When an asymmetric heat load disturbance and asymmetric resistance disturbance are incorporated into the system together or alone, the loop flow changes insignificantly in a certain interval; the anti-disturbance capacity of the system is strong in this interval. The resistance of the system to heat load disturbance is 0.2<k1<0.8, and the resistance disturbance is 0.6<B<4.8. When an asymmetric heat load and asymmetric resistance disturbance are simultaneously introduced into the system, an optimal resistance disturbance is achieved (k1∈[0.40,0.60] and B∈[0.7,2.9]).

Study Investigates Multiphase Flow in Circular and Triangular Pipes

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 208101, “Multiphase Flow in Circular and Triangular Pipes: Examining Flow Characteristics, Sand Erosion, and Heat Transfer Through Computational Fluid Dynamics and Experimental Work,” by Ronald E. Vieira, Thiana A. Sedrez, and Siamack A. Shirazi, SPE, The University of Tulsa, et al. The paper has not been peer reviewed. _ The authors present a survey of air/water and air/water/sand flow through circular and triangular pipes. The main objective of this investigation is to study the potential effects of triangular pipe geometry on flow patterns, slug frequency, sand erosion in elbows, and heat transfer in multiphase flow. Introduction The complete paper summarizes several important benefits of triangular pipes as compared with circular pipes in multiphase flow. First, a survey of horizontal multiphase air/water flow through circular and triangular pipes is presented. Second, the erosion patterns in triangular elbow geometry are examined experimentally and predicted computationally using existing erosion models. The results are compared with circular elbows for steel materials. Initially, an experimental investigation was performed using flow visualization with a paint-removal study to determine the location where particles impinge and lead to erosion. Erosion-measurement experiments are also conducted in a flow loop containing liquid and 300-µm sand particles. The experimental studies were followed by computational fluid dynamics (CFD) erosion modeling for liquid/sand and liquid/gas/sand flows in circular and triangular elbows. Third, an attempt is made to analyze the effect of circular and triangular pipe configurations on heat transfer at constant wall temperature and under the influence of different Reynolds number values. The analysis was performed numerically using CFD for turbulent and laminar flow with water at two different viscosities. Experimental Setups The main objective of the first set of experiments was to study the potential effects of triangular pipe geometry on flow patterns and slug frequency in gas/liquid flows. The experimental facility and methodology are detailed in the complete paper. The setup consisted mainly of a pump, tank, separator, and test-loop section (pipes). The water flow rate (containing particles) was measured by timing the liquid volume loss from the tank. Measurements were repeated three times, and the averaged measured time was used. The gas-flow rate was measured using a digital vortex flowmeter. Experiments were performed horizontally and near atmospheric pressure conditions. The circular test section consisted of a 2-in.-inner diameter, 28-ft-long clear acrylic pipe. The triangular test section was formed from three 7-ft-long, 2.7-in.-wide sheets of cast acrylic. The effect of corners of the triangular pipe on the liquid distribution compared with round tubes was investigated using two different orientations of triangular pipe, apex upward and downward. Detailed videos and slug-frequency measurements were collected for horizontal air/water flow through the round and the triangular clear pipes to identify flow patterns. The slug frequency was measured by analyzing the videos.

Efficient adsorptive removal of diclofenac sodium by acidified MIL101(Cr): optimizing the content of phosphotungstic acid, flow loop thin film slurry flat plate reactor

Efficient adsorptive removal of diclofenac sodium by acidified MIL101(Cr): optimizing the content of phosphotungstic acid, flow loop thin film slurry flat plate reactor

Measurement of Mass Transfer Intensity in Gas–Liquid Medium of Bioreactor Circuit Using the Thermometry Method

The development of energy-efficient solutions for large-scale fermenters demands a deep and comprehensive understanding of hydrodynamic and heat and mass transfer processes. Despite a wide variety of research dedicated to measurements of mass transfer intensity in bubble flows, this research subject faces new challenges due to the topical development of new innovative bioreactor designs. In order to understand the fluid dynamics of the gas–liquid medium, researchers need to develop verified CFD models describing flows in the bioreactor loop using a progressive physical and mathematical apparatus. In the current paper, we represent the results of evaluating the key performance indicator of the bioreactor, namely the volumetric mass transfer coefficient (kLa) known as a parameter of dominant importance for the design, operation, scale-up, and optimization of bioreactors, using the developed thermometry method. The thermometry method under consideration was examined within a series of experiments, and a comparative analysis was provided for a number of various regimes also being matched with the classical approaches. The methodology, experiment results, and data verification are given, which allow the evaluation of the effectiveness and prediction of the fluid flows dynamics in bioreactors circuits and ultimately the operational capabilities of the fermenter line.

A Highly Accurate Mathematical Model for Analyzing Modular Multilevel Converters in Transformer-Less Applications

Transformer-less connection schemes can provide a feasible solution for lowering the economic cost, occupied space, and device weight of modular multilevel converter (MMC) systems. However, due to the reduction in the converter transformer, the current flow loop is changed; as a result, the existing MMC model is not suitable. In this paper, the ac- and dc-side equivalent circuit models of the MMC system using a transformer-less connection scheme are established in both a–b–c stationary and d–q rotating coordinate systems. Then, a highly accurate mathematical analysis model is proposed, in which the interactions among the electrical quantities can be fully seen. The mathematical model is established in the time domain, and hence the amplitude and phase angle of every harmonic component in each quantity can be directly obtained. The proposed model is verified under various typical situations by comparing the calculated values with the actual waveforms. The comparison results prove that the calculation error is small enough to be negligible. The mathematical model in this paper can provide a powerful tool in terms of the performance analysis and the main circuit parameter design for MMCs in transformer-less applications.

NaA zeolite-clay composite membrane formulation and its use as cost-effective water softener

The present study describes the exchange of calcium and magnesium ions through an active layer of zeolite Na-A deposited on flat porous support made from clay. Microfiltration membrane's supports are prepared by uniaxial pressing dry mixture of clay, and 3% w/w activated carbon then sintered to 1000 °C. The zeolite Na-A (LTA) layer is deposited on the clay support using the hydrothermal method. An increase in the specific surface area and the pore volume and a decrease in pore diameter after deposition of the zeolite Na-A on the support is observed. SEM analysis of the zeolite Na-A shows well-defined cubic crystals with sizes between 1.3 and 2.4 μm. The efficiency of the zeolite membrane for the exchange of calcium and magnesium ions with the sodium (Na) within the zeolite-A cavities was evaluated by filtration tests of solutions containing chlorides salts of the two metals using a flow loop adjusted for dead-end filtration. The obtained results show that the Na+ ions of Zeolite-A were completely exchanged with Ca2+ and Mg2+ and that the maximum retention on the zeolite membrane reached 93.3% and 72.1% for Ca2+ and Mg2+ ions, respectively after 30 min of filtration. The electrochemical impedance spectroscopy (EIS) has shown an electron transfer increase of the membrane paste electrode exchanged with Ca2+, Mg2+ as single ions or as mixture, with a preference for Ca2+ compared to Mg2+, indicating that a combination of exchange and size exclusion mechanisms must be used to explain the membrane behavior. These properties make the zeolite Na-A membrane a suitable material that could be used effectively in the softening of hard water.

Effect of SDS on the Formation and Blockage Characteristics of the CH4 Hydrate in a Flow Loop

Effect of SDS on the Formation and Blockage Characteristics of the CH₄ Hydrate in a Flow Loop

Abstract 12169: Re-Imagining Fontan Support: Novel Cavopulmonary Connection Can Accommodate Mechanical Circulatory Support, Augment Cardiac Output and Balance Hepatic Flow

Introduction: Improved Fontan survivorship requires novel treatments for late complications and inevitable failure. Typical total cavopulmonary connection (TCPC) shapes perform well in the short term yet competitive flows create challenges in providing mechanical circulatory support (MCS) due to two inflows/outflows. A novel, feasible Fontan shape, the Convergent Cavopulmonary Connection (CCPC), converges venous return to create a single inflow and outflow for easy institution of MCS, and maintains favorable hepatic flow distribution (HFD) and power loss. The impact of MCS on CCPC hemodynamic performance is still unknown. Hypothesis: In vitro implantation of a single MCS device into patient-specific CCPCs will be feasible and produce augmented cardiac output and acceptable HFD, compared to traditional TCPC. Methods: A benchtop mock circulatory flow loop using 60/40 glycerin equipped with inlet/outlet flow meters and outflow optical registers was used to analyze five 3D-printed TCPC and CCPC models derived from cardiac MRI images. Patient-specific flow conditions were applied to each model’s inlets/outlets. HFD was measured using an injection of blue tracer dye in the IVC and the optical concentration at the LPA and RPA outlets was compared. The CCPC models were also retrofitted to accommodate an Impella ventricular assist device (VAD) and PediPump VAD. HFD and cardiac index (CI) (IVC+SVC flow return) were compared with linear regression and paired t-test. Results: All CCPC HFD were within optimal range. Addition of either MCS device to the CCPC creates incremental increase of CI (p&lt;0.01) and significant improvement in HFD balance vs baseline TCPC (p=0.03), reflecting the dominance of the MCS mixing over anatomic influence on HFD. Conclusions: Patient-specific CCPC Fontan designs can successfully accommodate MCS implantation. Addition of MCS in benchtop testing shows improved CI and HFD, mitigating anatomic impact on HFD.

Technology Focus: Flow Assurance (November 2022)

Now thankful for the continuing recovery from the health and business effects of COVID-19, I sincerely hope that all JPT readers continue to remain safe, healthy, and busy. Nevertheless, flow assurance effects from slugging and various types of solids deposition during engineering, design, maintenance, and operations still create challenging technical issues needing safe, economical solutions. The recurring long-term mitigation of multiple slugging and flow assurance phenomena such as the deposition of wax, erosion, asphaltenes, corrosion, and salt, still demands attention and considerable technical effort. Hydrodynamic slugging (or two-phase liquid/gas flow instability) in pipelines has caused flow capacity loss and intense vibration at the separator. Paper IPTC 22235 describes how this issue can be resolved using foams generated from surfactants introduced into the pipeline to entrap and slow down gas flow. The foam’s behavior was simulated using conventional OLGA (short for “oil and gas”) simulation software. This study showed that foams were able to slow gas velocity sufficiently and reduced liquid fluctuations, thus reducing slugging in a Malaysian pipeline. Accurate foam-viscosity measurements generated from the laboratory are a vital input to the model to understand the behavior of foam and quantify its effect before actual field applications. In the absence of flow loops to simulate slugging in pipelines and to validate the foam’s behavior, the use of the OLGA software still provides the necessary confidence in the application of foams to save time and reduce laborious and complex experimentations. The work described in paper SPE 209475 focuses on detailed investigation of magnesian calcite as the main deposition constituent of solids fouling several onshore and offshore operations of a major operator in the North Sea and Caspian regions. These solids can and do occur as a conventional scale that has perhaps hidden the extent of their prevalence in offshore and onshore operations involving fouling of tubing and restricting production, impeding operation of subsurface safety valves, reducing the efficiency of heaters and coolers offshore, and plugging strainers in the produced-water handling systems offshore. This paper describes how this “pseudoscale” was detected and its prevalence, using field case examples from several operated and nonoperated assets. It describes the theories developed to rationalize magnesian calcite deposition onto production surfaces. The paper then shares dispersant chemical field-trial-performance data and the deployment of electromagnetic fields to determine the effect of changing the zeta potential on the attraction of fine magnesian calcite particles to the surface and, thus, the effect on the fouling rate. Paper OTC 32059 describes an alternative to constant chemical injection or thermodynamic controls such as insulation or heating: the incorporation of a robust omniphobic surface treatment material that has been shown to significantly reduce the adhesion of flow assurance solids, resulting in lower risk for deposition and plugging by gas hydrates, waxes, and asphaltenes. As part of a US Department of Energy study, laboratory-scale tests were performed on a variety of apparatuses. While the results from these tests are promising, some disconnects between the laboratory-scale observations and field-scale testing still exist. The papers highlighted here for suggested additional reading focus on three areas requiring further new analytical tools while providing safe, cost-effective, and reliable operations for flow assurance. These papers present potential novel applications of nanomaterials for flow-restriction detection, slug modeling in flowline bends, and liquid-slugging detection using pressure monitoring. I hope you find them interesting, informative, and technically helpful and appreciate this opportunity to disseminate these technology options to you in this Technology Focus. In addition, I invite you to participate in the Flow Assurance Technical Section to augment more learning on other topics. Finally, I wish the full and complete recovery of your family, work, and SPE activities during these challenging times during the recovery of oil and gas. I have very much enjoyed providing you the latest developments in flow assurance over the past few years and wish you all the best. Recommended additional reading at OnePetro: www.onepetro.org SPE 208233 Slug-Frequency-Prediction Model for Fluid Flow in Flowline Bends by Loveday Igbokwe, Memorial University of Newfoundland, et al. IPTC 22459 Pressure Characteristics of Slug Flow in Horizontal Pipes by Ala AL-Dogail, King Fahd University of Petroleum and Minerals, et al. OTC 31804 Use of Nanomaterials for Early Detection of Flow-Restricting Substances by Stephen George Louis, Albastron Technologies, et al. SPE 209306 Visualization of Liquid Slugging Using Detailed, High-Quality Pressure Monitoring by Ryan David Gordon, Toku Systems, et al.