Pump Pressure Research Articles

An Adaptive Ensemble Approach Using Online Global and Local Models for Pump Pressure Prediction in Well Cementing Operations

Summary In cementing operations, conventional methods for predicting wellhead pump pressure, which rely on empirical and numerical models, often fall short regarding real-time accuracy and adaptability to different geological blocks and cementing techniques. These shortcomings hinder precise control of the wellhead pressure range, impacting operational safety, efficiency, and on-site personnel guidance. Furthermore, traditional offline machine-learning models cannot handle concept drift due to changing downhole fluid conditions during cementing. This paper frames wellhead pump pressure prediction as an online regression forecasting problem that utilizes the strengths of incremental and online ensemble learning with the Hoeffding tree regressor to overcome these challenges. First, data features are partitioned into subsets to create base learners, and then global and local models are deployed to address concept drift. The dynamic integration of these models significantly improves adaptability and performance. Experimental results confirm the superiority of our method over existing approaches. Compared with the suboptimal online models, mean squared error (MSE) is reduced for pump pressure prediction in five cementing data sets by 74.65%, 75.09%, 59.27%, 65.21%, and 70.01%, respectively. Additionally, MSE is reduced by 52.46%, 51.18%, 42.93%, 57.12%, 56.23%, 64.83%, and 79.51%, respectively, in seven open data sets, which showcases the broad applicability of our method to other regression tasks.

Investigations to reduce rarefied gap flows within positive displacement vacuum pumps by utilising surface structures

Abstract The ultimate pressure and efficiency of positive displacement vacuum pumps is limited by the backflow through the gaps within the machines. These gap flows are typically reduced by decreasing the gap height, which is limited for reasons of operational safety. Therefore, this study concentrates on the reduction of rarefied gap flows by means of suitable surface structures whose dimensions are small compared to the gap height without simultaneously reducing the minimum gap height. For this purpose, a method is presented to efficiently calculate the impact of the surface structure on these gap flows. Based on this method, design parameters for the choice of a suitable surface structure are discussed. Furthermore, a possible transfer for the application on the rotors is shown including a proposal for the machining process.

Numerical simulation study of vortex cavitation and induced pulsation characteristics in spiral lobe pumps

Lobe pumps are used in many different sectors because of their versatility and effectiveness for managing multiphase flows. In this study, three-dimensional unsteady numerical simulations are performed to evaluate the vortex cavitation phenomenon in these pumps. The work combines dynamic meshing techniques, advanced vortex recognition methods, and a full cavitation model to provide insight into the genesis, evolution, and influence of vortex cavitation on pump performance. The results of the study demonstrate that under high-speed and high-pressure conditions, vortex flow occurs at the edge of the rear of the rotor lobe in the suction chamber of the lobe pump, resulting in the production of vortex cavitation. Cavitation is most strong at the core of the vortex, while the degree of cavitation at the edge of the vortex gradually diminished. The gas volume fraction reduces from 0.135 to 0.0832, and this makes the pressure decrease from 1.055 to 1.02 MP. The process of genesis, development, and removal of vortex cavitation is cyclic. At different levels of cavitation, the degree of pulsation in pump outlet flow, pressure, and radial force increases with increasing cavitation. Periodic vortex cavitation leads to periodic changes in pump output pressure, flow rate, radial force, and axial force.

Flow field and performance analysis of downhole pipe string in single-well injection-production technology

High water content is a critical issue that must be urgently addressed in the current oilfield development, and the single-well injection-production technology (SWIPT) is an effective approach for achieving economical extraction in high-water-content oilfields. To meet the 5.5-inch casing size requirements, further improve SWIPT performance, and minimize the impact of pump pressurization on the subsequent oil–water separation process, dual-pump suction-SWIPT is proposed and an axial-flow cyclone separation pipe string is designed. A theoretical fluid–solid interaction (FSI) model of the downhole pipe string (DHPS) applicable to SWIPT is established through vibration testing and data analysis. Based on the new FSI model-corrected numerical simulation method, single-factor experiments are performed to analyze the medium transport process and oil–water separation performance within the flow field under structural vibration disturbances. The results indicate that the separation of fluid media within the single-well injection-production DHPS is not significantly affected by structural interference. The simulation results closely matched the experimental data, with the average error of the axial velocity at different test points being within 0.041 m/s. In the transport pipe regions, minor variations in the velocity and pressure fields are observed under vibration conditions. Under an inlet flow rate of 4 m3/h, split ratio of 30%, and oil volume fraction of 1%, the optimal separation efficiency of 97.26% is achieved. This study provides new insights for the development and application of SWIPT.

Direct simulations of bedrock core and cuttings transport phenomena in reverse circulation drilling

Polar drilling is essential for obtaining ice and bedrock samples, providing critical insights into climate and geological history. The reverse circulation drilling method, utilizing a dual-wall drill pipe, presents a stable and efficient strategy. Nonetheless, the intricate dynamics involving drilling fluids, rock cuttings and cores necessitate sophisticated modeling to elucidate the underlying mechanism and optimize drilling efficiency. To address this, we developed a multiphase flow model that accounts for non-Newtonian fluid behavior, turbulence, particle dynamics, and fluid–structure interactions, enabling a thorough assessment of various operational parameters. The model's temporal–spatial sensitivity was evaluated, and its accuracy was confirmed by comparison with three different sets of experimental data. A detailed parametric investigation was then conducted to systematically assess the effects of various parameters, including the non-Newtonian behavior and inlet velocity of the drilling fluid, the rate of penetration, and the dimensions of the cuttings and core. The simulation results indicate that the non-Newtonian behavior of the drilling fluid has an non-negligible effect on the transport efficiency of both cuttings and core. An increase in the fluid inlet velocity leads to faster transport, albeit at the cost of higher pump pressure. The rate of penetration has a minor influence on the core transportation but largely affects the cutting transportation. More interestingly, larger cuttings demonstrate enhanced transport efficiency, attributed to a more uniform velocity distribution. Furthermore, the core diameter plays a pivotal role in transport efficiency by significantly altering the fluid dynamics, whereas the core length has a negligible effect. These results may have direct applications for optimizing polar drilling operations, potentially leading to enhanced drilling efficiency, reduced drilling costs, and informing future drilling technology advancements.

Development of a Microphysiological Cartilage-on-Chip Platform for Dynamic Biomechanical Stimulation of Three-Dimensional Encapsulated Chondrocytes in Agarose Hydrogels.

Osteoarthritis (OA) is one of the most prevalent joint diseases globally, characterized by the progressive breakdown of articular cartilage, resulting in chronic pain, stiffness, and loss of joint function. Despite its significant socioeconomic impact, therapeutic options remain limited, largely due to an incomplete understanding of the molecular mechanisms driving cartilage degradation and OA pathogenesis. Recent advances in in vitro modeling have revolutionized joint tissue research, transitioning from simplistic two-dimensional cell cultures to sophisticated three-dimensional (3D) constructs that more accurately mimic the physiological microenvironment of native cartilage. Over the last decade, organ-on-chip technologies have emerged as transformative tools in tissue engineering, offering microphysiological platforms with precise control over biomechanical and biochemical stimuli. These platforms are providing novel insights into tissue responses and disease progression and are increasingly integrated into the early stages of drug screening and development. In this article, we present a detailed experimental protocol for constructing a cartilage-on-chip system capable of delivering controlled dynamic biomechanical stimulation to 3D-encapsulated chondrocytes in an agarose hydrogel matrix. Our protocol, optimized for both bovine and human chondrocytes, begins with Basic Protocol 1, detailing the preparation and injection of cell-laden hydrogels into the microdevice. Basic Protocol 2 describes the application of dynamic mechanical loading using a calibrated pressurized pump. Finally, Basic Protocols 3 and 4 focus on the retrieval of the hydrogel and RNA extraction for downstream molecular analyses. This platform represents a critical advancement for in vitro studies of cartilage biology, enabling more precise modeling of OA pathophysiology and evaluation of experimental therapeutics. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Cartilage-on-chip injection Basic Protocol 2: Cartilage-on-chip actuation Basic Protocol 3: Cartilage-on-chip agarose hydrogel removal Basic Protocol 4: Preparation of cartilage-on-chip for RNA extraction.

Comparison of the safety of flexible ureteroscopy with the different irrigation methods in a 3D print kidney model.

To compare intrarenal pressure (IRP) and irrigation flow by varying suspended water heights and hand-held pressure pumping during flexible ureteroscopy using an in vitro 3D printed kidney model. A 3D-printed silicone model was used to simulate the kidney. The ureteral access sheath(UAS) was connected to the kidney model and positioned at the ureteropelvic junction. Central venous pressure tubing was used to monitor the pressure in the renal pelvis under different conditions. Sheath sizes of 12Fr and 14Fr were tested with flexible ureteroscope (fURS) sizes of 7.5, 8.5, and 9.5Fr, respectively. The irrigation was gravity-based, with suspended water heights set at 60, 90, 120, 150, and 180cm. The manual pumping as another set of measurement is used to measure the maximum intrarenal pressure. Using a 12Fr sheath with a 9.5Fr fURS loading without additional accessories resulted in IRP ranging from 8.4 to 17.5 cmH2O, while manual pumping perfusion pressure exceeded 60 cmH2O. Loading a 200-um laser fiber reduced the pressure to 6.4-10.5 cmH2O, and using a stone basket decreased it to 4.0-5.0 cmH2O. Using a 14Fr sheath with a 9.5Fr fURS resulted in an IRP of 2.5-6.0 cmH2O, compared to 17 cmH2O with manual pumping. With a 12Fr sheath and a 7.5Fr fURS, the IRP ranged from 5.4 to 8.2 cmH2O, while manual pumping resulted in 25.5 cmH2O. With a 14Fr sheath and a 7.5Fr fURS, the IRP ranged from 1.5 to 4.3 cmH2O, and manual pumping resulted in 9.0 cmH2O. When using a UAS in a flexible ureteroscopy, the IRP can be maintained within a safe range with different fURS/UAS combos with a suspended water height of less than 180cm. However, with specific fURS/UAS(9.5Fr/12Fr) combos, the IRP exceeded the safe limit when using manual pumping. Gravity irrigation with a suspended water height of less than 180cm is safe in this simulated clinical environment.

Comparative study on the performance of fresh concrete comprising manufactured sand vs. river sand during full-scale long-distance pumping

The shift from river sand (RS) to manufactured sand (MS) as a fine aggregate in concrete is driven by environmental sustainability concerns. However, negative impacts of MS on concrete workability have raised doubts about its suitability for long-distance pumping in construction projects. This study evaluates the performance of MS concrete compared to RS concrete of the same strength grade during long-distance pumping. A full-scale coiled pipeline with measured length of 348 m was built, twelve batches of C30 and C60 concrete were prepared, and pumping tests were conducted at discharge rates of 2.5–18.9 liter per second (L/s). The workability and rheological parameters were assessed before and after pumping. The measured and predicted pumping pressure were analyzed and calculated based on rheological parameters and lubricating layer (LL) parameters. Results indicate that MS increased the yield stress and decreased the LL thickness index of C30 concrete, while it decreased the viscosity coefficient of C60 concrete. Post-pumping, the change in yield stress was similar for both MS and RS concrete, but MS reduced the plastic viscosity change in C60 concrete. MS did not significantly affect the pumping pressure loss, but influenced the pumping pressure prediction deviation by influencing the thixotropy. The classic pumping pressure prediction model developed by Kapan obviously overestimated the pumping pressure during long-distance pumping, and the deviation was more prominent in high-strength concrete pumping. MS increased the thixotropy of C30 concrete and reduced the prediction deviation of pumping pressure, but had the opposite effect on C60 concrete.

Research on dynamic well control in riserless mud recovery system

In order to promote the development of RMR (Riserless Mud Recovery) system well control technology and ensure the safe operation of deep water drilling operations, the overflow control equation of RMR system considering the lifting force of subsea pump is established and verified, the conventional overflow monitoring method and the overflow monitoring method based on subsea pump parameter variation are compared and analyzed. the dynamic well control process of the RMR system after overflow under the two modes of constant subsea pump displacement and constant inlet pressure of subsea pump is simulated, and the influencing factors of inlet pressure of subsea pump are further analyzed. The results show that although the temperature effect is taken into account in the model established in this paper, the time error of the mud pool increment, the inlet pressure and the displacement of subsea pump after reaching the overflow criterion is less than 22.5% compared with Froyen's model. The conventional overflow monitoring method has fast response and small change, while the overflow monitoring method based on subsea pump parameter change is on the contrary, and the two should be used together. Both the constant inlet pressure of subsea pump mode and the constant subsea pump displacement mode can control overflow, but from the stability of subsea pump, service life and well control safety, the constant displacement mode is better. In the case of large formation pressure, low drilling fluid density, overflow criteria and circulating displacement, the pressure response adjustment speed of the subsea pump inlet is faster, and the back pressure load of the subsea pump inlet can be effectively alleviated by appropriately increasing the circulating displacement and drilling fluid density. This study has enriched the theoretical system of RMR system in overflow control, and has certain guiding significance for the development of deepwater and ultra-deepwater drilling safety technology.

Machine-Learning Approach PredictsGel Strength of Drilling Fluid While Drilling

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 35433, “Novel Machine-Learning Approach for Predicting the Gel Strength of the Drilling Fluid While Drilling,” by Ahmed Gowida, SPE, and Salaheldin Elkatatny, SPE, King Fahd University of Petroleum and Minerals. The paper has not been peer reviewed. Copyright 2024 Offshore Technology Conference. _ Accurately estimating gel strength is paramount for optimizing drilling operations and preventing cuttings from settling at the wellbore’s bottom. Traditional methods rely on rotational viscometers, which are time-intensive, equipment-dependent, and lack real-time monitoring capabilities. This study underscores the feasibility of leveraging machine learning (ML) as a practical tool for predicting drilling-fluid gel strength, offering real-time monitoring and precise predictions to enhance drilling efficiency, safety, and automation initiatives. Background The gel strength of drilling fluid is assessed using a viscometer, focusing on the 3-rev/min reading obtained after agitating the fluid at 600 rev/min to disrupt any gel formation. Initially, the measurement is taken when the mud reaches a static state for 10 seconds. Subsequent readings are conducted at 10- and 30-minute intervals. The rationale behind the 30-minute reading lies in its ability to indicate whether the mud forms a substantial gel during prolonged static periods, such as when tripping out a bottomhole assembly. Elevated gel strength may result in increased pump pressure required to restore circulation after extended static conditions. Additionally, a consistent upward trend in the 30-minute gel strength suggests the accumulation of ultrafine solids. Consequently, appropriate measures such as chemical treatments or dilution with fresh base fluid are necessary to address this issue. The frequency of measuring various fluid properties is tailored to their respective effects on well-control and drilling operations. These frequent evaluations allow for timely adjustments and monitoring of rheological measurements, offering valuable insights into rock sensitivity and the performance of mud activity and stability after exposure to drilled formations. On the other hand, a complete mud test (including all mud rheological properties) is performed twice a day because it consumes considerable time. It has been observed that mud rheological properties exhibit a significant correlation with two fundamental mud properties: mud weight and Marsh funnel (MF) viscosity. To the best of the authors’ knowledge, a dearth of research exists in the literature aimed at predicting the gel strength of drilling fluid using ML techniques. Consequently, this research endeavor introduces a novel ML model designed specifically for forecasting the gel strength of synthetic oil-based mud systems. Such predictive models are poised to enhance drilling performance by optimizing mud functions. Leveraging MF and mud-density measurements, the developed models aim to forecast the rheological properties of drilling fluid, thereby facilitating improved monitoring of mud functionality during drilling operations at the rig site.

Experimental and numerical study on cavitation pulsating pressure of water-jet propulsion axial-flow pump.

Cavitation may occur in water-jet pump during operation of water-jet propulsion vessel, and once cavitation occurs, the tip clearance pulsating pressure of the impeller may be intensified, resulting in increased vibration of the water-jet propulsion unit. In this paper, the cavitation pulsating pressure characteristics at different positions in the pump are studied by experiment and numerical simulation, and the pulsating pressure characteristics in tip clearance are mainly researched. Based on Star-CCM+ commercial software, unsteady Reynolds-averaged Navier-Stokes equations(RANS) numerical simulation is carried out, and the feasibility of the numerical simulation method is verified by uncertainty analysis. The results show that the cavitation pulsating pressure near the leading edge of the impeller in the tip clearance is the largest. The variation of the tip clearance pulsating pressure with the intensification of cavitation is studied by numerical simulation, and its mechanism is revealed. A dimensionless coefficient of net positive suction head (CNPSH) is proposed, and the study shows that the cavitation pulsation pressure coefficients of pumps of different scales are equal when the working conditions are similar and the CNPSH are equal, which indicates that the cavitation pulsating pressure performance of full scale pump can be predicted by model scale. It is of great significance to evaluate the vibration performance of the full scale water-jet propulsion.

Oil recovery and cooling for underground salt cavern oil storage: Insights from coupled flow and thermal model

Petroleum reserve in salt caverns is paying more attention to oil cooling to prevent dissolved gas release from heated crude oil. This work introduced a method for oil recovery in conjunction with cooling, along with a matching flow and heat transfer model taking changes in crude oil thermophysical parameters into consideration. An average error of 3.43% was observed between the model results and filed monitoring data. It was found that after being cooled by the heat exchanger, the temperature of extracted crude oil drops from 39.5 °C to 26.8 °C, demonstrating the effectiveness of this approach for oil cooling. Sensitivity analysis indicates that the season is the primary determining factor for the cooling efficacy of crude oil. Even worse, cooling will be useless when the ambient temperature exceeds 35 °C. However, increasing brine temperature will reduce the surface pumping pressure from 7.60 MPa to 5.17 MPa, with a decrease of up to 31.97%. A special focus was given to the brine injection rate, which seemed to have less impact on the cooling efficiency but became more significant in the pressure profile. In addition to providing further insights into the flow and thermal performance of strategic petroleum reserves in the salt cavern, this study could also be a powerful tool for determining the best process parameters to ensure the delivery temperature of crude oil and the stability of the salt cavern.

Lubrication, Friction and Wear Characteristics of Textured Surface Slipper Pairs in Axial Piston Pumps

The study investigates the impact of textured surface parameters and pump operating parameters on the friction performance of slipper pairs in axial piston pumps. The orthogonal experimental scheme was developed, and the influence of several factors was explored, such as rotational speed, area ratio, micro-pit shape, diameter, depth-to-diameter ratio and film thickness. Optimal dimension combinations of the micro-pit were identified by numerical simulation and standard pin–disk friction experiment. In the pin–disk friction pair test, the friction coefficient of the textured surface compared to the smooth surface showed a maximum average friction reduction rate of 26.974%. Under various pump pressures (4, 8, 12 MPa) and pump displacements (10, 20, 35 L/min), the friction reduction rates of the textured surface slipper pairs (texture diameter 500 µm, depth 250 µm, area ratio 20%) ranged from 0.78% to 18.13%. The study underscores the importance of surface texture in enhancing the operational efficiency and reliability of axial piston pumps, offering valuable insights for the design and maintenance of hydraulic pumps.

Determination of Lubrication Layer Thickness and Its Effect on Concrete Pumping Pressure.

The flow of six kinds of fresh concrete under different flow rates and lubrication layer thickness (TLL) values in the horizontal pipe was numerically simulated. The influence of the TLL on the pressure per unit length (PL) was analyzed. It was determined that the formation of the lubrication layer (LL) significantly reduces the PL in concrete pumping. As the TLL increased, the PL decreased. However, the degree of reduction in the PL gradually decreased as the TLL increased. Relating the simulated PL with the experimental PL, the size of the TLL was obtained, which was between 1 and 3 mm. The minimum and maximum were 1.23 and 2.58 mm, respectively, and the average value was 1.97 mm. The strength (S24, S50), the size of the aggregate (A10, A20, A25), and the flow rate of pumping all affected the TLL. The type of fresh concrete and the flow rate of pumping significantly affected the PL, which impacted the TLL. However, the TLL also impacted the PL. Finally, this made the TLL change within a certain range. When PL > 14,000 Pa/m, 2 mm < TLL< 3 mm; on the other hand, 1 mm < TLL< 2 mm. Therefore, we can use CFD to simulate the flow of all types of concrete in the actual pumping pipeline with a TLL of 2 mm to obtain their pumping pressure and guide the actual construction.

Simulation analysis and experimental research on static performance of water-hydraulic pressure difference control valve

Many hydraulic tools, like hydraulic cylinders and hydraulic artificial muscle joints are operated by adjusting pressure differences between different zones. Typically, the method employed to change the pressure difference is establishing hydraulic bridges and adjusting liquid resistance. While effective, this method's drawback is complex structures. To address this issue, a water-hydraulic pressure difference control valve, integrating two hydraulic bridges, was designed. The static performances including the output pressure difference, the flow rate and the force acting on the valve core were analyzed using AMESim and computational fluid dynamics simulations. Based on the simulation results, a prototype of voice coil motor direct drive pressure difference control valve was manufactured and the corresponding experiments were carried out. The computational fluid dynamics simulation results show that the internal leakage and the through-flow capacity difference between throttling grooves affect the flow field characteristics of the valve. When the pump pressure is 3 MPa and the valve opening is at the middle position, the internal leakage increases the flow rate from 2.25 L/min to 2.38 L/min, and the through-flow capacity difference reduces the control port pressure from the theoretical analysis of 1.5 MPa–1.41 MPa. Furthermore, combined with the analysis of the external liquid resistance, the AMESim model of the pressure difference control valve is modified. When the pump pressure is 3 MPa, the pressure difference and flow rate average deviations between the modified AMESim model and the experiment are 0.021 MPa and 0.048 L/min. Finally, a rotational angle experiment for a water hydraulic artificial muscle joints showed satisfactory control effects, suggesting the valve's application in controlling hydraulic tools and actuators.

Efficient management and compliance check of HVAC information in the building design phase using Semantic Web technologies

Several OWL ontologies have been developed for the AEC industry to manage domain-specific information, yet they often overlook the domain of building services and HVAC components. The Flow Systems Ontology was recently proposed to address this need, but it does not include HVAC components’ size and capacity-related properties. Also, despite their strengths in representing domain-specific knowledge, ontologies cannot efficiently identify poor data quality in BIM models. A four-fold contribution is made in this research paper to define and improve the data quality of HVAC information by (1) extending the existing Flow Systems Ontology, (2) proposing the new Flow Properties Ontology, (3) proposing an HVAC rule set for compliance checking, and (4), moreover, we use Semantic Web technologies to demonstrate the benefits of efficient HVAC data management when sizing components. The demonstration case shows that we can represent the data model in a distributed way, validate it using 36 SHACL shapes and use SPARQL to determine the pressure and flow rate of fans and pumps.

Energy costs of the sponge pump

Sponges pump large volumes of water to obtain nutrition from a dilute suspension of food particles and dissolved organic matter. Our review of the literature shows pumping power ranging from 0.85% up to 28% of the total metabolic respiration rate Rtot, where the pumping power (Pp = pumping rate × pump pressure) is the energy per unit time transferred to the water flow. Some published values of pumping costs are high while others are low due to incorrect estimates of some pressure losses in the aquiferous system of sponges. However, as improved descriptions of detailed structures and function, especially of the filter apparatus of the choanocytes, have become available, our corrected values for pressure losses show the respiration-specific pumping costs of Pp/Rtot = 1.3 to 22%. The stated pumping cost is based on the minimal (theoretical) pump power delivered to the water, which excludes a mechanical efficiency of pump action and a metabolic efficiency that expresses the fraction of total metabolism that is devoted to driving the pump action, considerations that should be included in future studies.

Blood trauma in veno-venous extracorporeal membrane oxygenation: low pump pressures and low circuit resistance matter

BackgroundVeno-venous extracorporeal membrane oxygenation (VV ECMO) has become standard of care in patients with the most severe forms of acute respiratory distress syndrome. However, hemolysis and bleeding are one of the most frequent side effects, affecting mortality. Despite the widespread use of VV ECMO, current protocols lack detailed, in-vivo data-based recommendations for safe ECMO pump operating conditions. This study aims to comprehensively analyze the impact of VV ECMO pump operating conditions on hemolysis by combining in-silico modeling and clinical data analysis.MethodsWe combined data from 580 patients treated with VV ECMO in conjunction with numerical predictions of hemolysis using computational fluid dynamics and reduced order modeling of the Rotaflow (Getinge) and DP3 (Xenios) pumps. Blood trauma parameters across 94,779 pump operating points were associated with numerical predictions of shear induced hemolysis.ResultsMinimal hemolysis was observed at low pump pressures and low circuit resistance across all flow rates, whereas high pump pressures and circuit resistance consistently precipitated substantial hemolysis, irrespective of flow rate. However, the lower the flow rate, the more pronounced the influence of circuit resistance on hemolysis became. Numerical models validated against clinical data demonstrated a strong association (Spearman’s r = 0.8) between simulated and observed hemolysis, irrespective of the pump type.ConclusionsIntegrating in-silico predictions with clinical data provided a novel approach in understanding and potentially reducing blood trauma in VV ECMO. This study further demonstrated that a key factor in lowering side effects of ECMO support is the maintenance of low circuit resistance, including oxygenators with the lowest possible resistance, the shortest feasible circuit tubing, and cannulae with an optimal diameter.

Irreversibility analysis in an electro‐osmotically driven flow using ternary hybrid nanofluids in a microchannel with a porous material

AbstractFlow enhancement is one of the most significant challenges in microfluidics with extremely low permeability. Based on this, electrokinetics remediation for the double‐layer flow of hybrid ternary nanofluid is proposed based on the transport of ions under constant pumping pressure. The entropy generation volumetric rate relation is also modeled. The nonlinear system of equations is formulated, solved, and validated numerically by the collocation method and shooting Runge–Kutta method. Results are shown graphically to explore the impacts of governing parameters, such as the Darcy parameter, viscosity index, electrokinetic, and Joule heating effects, on the velocity, temperature, entropy, and Bejan number profiles. The flow and heat transmission in microchannels may be significantly changed and controlled by the electric double layer. The findings show that as the electrokinetic parameter's magnitude increases, the flow is slowed down, and thermal dispersion is impeded by nanoparticle collisions, which lowers the velocity field and heat transfer profile.

Effect of a Preoperative Subacromial Epinephrine Injection on Visualization During Shoulder Arthroscopic Surgery: A Randomized Controlled Trial.

The addition of epinephrine to arthroscopic irrigation fluid has been shown to improve surgeon-rated visual clarity during shoulder arthroscopic surgery. Subacromial injections of epinephrine are also used for this purpose. To assess the influence of a preoperative subacromial epinephrine injection on surgeon visualization during subacromial shoulder arthroscopic surgery. It was hypothesized that the epinephrine injection would improve surgeon-rated visual clarity. Randomized controlled trial; Level of evidence, 1. A double-blind randomized controlled trial including adult patients undergoing shoulder arthroscopic surgery in the beach-chair position requiring visualization of the subacromial space was performed. Patients in the epinephrine group (n = 30) received a preoperative subacromial injection of bupivacaine and epinephrine, and those in the control group (n = 30) received a preoperative subacromial injection of bupivacaine. Epinephrine was added to the first 10 L of arthroscopic irrigation fluid in all patients. The primary outcome was surgeon-rated visual clarity throughout the procedure that was recorded at the end of the procedure using a visual analog scale (VAS) scored from 0 (worst) to 10 (best). Secondary outcomes included an increase in pump pressure during the procedure, total operative time, and the intraoperative use of blood pressure-modulating medications. Rotator cuff repair was performed in 88.3% of patients (25/30 epinephrine; 28/30 control), with multiple procedures performed in 85.0% of patients (23/30 epinephrine; 27/30 control). The VAS score for visual clarity was slightly better in the epinephrine group compared with the control group, although the difference was neither statistically nor clinically significant (8.3 ± 1.4 vs 7.5 ± 1.8, respectively; P = .09). There was no difference between the epinephrine and control groups in the need for an increase in pump pressure to improve visualization (8/30 [26.7%] vs 7/30 [23.3%], respectively; P > .99), total operative time (62.0 ± 19.4 vs 64.0 ± 30.1 minutes, respectively; P = .90), or the intraoperative use of blood pressure-modulating medications (20/30 [66.7%] vs 17/30 [56.7%], respectively; P = .60). There were no perioperative adverse events in either group. The addition of a subacromial epinephrine injection before shoulder arthroscopic surgery resulted in a small improvement in visual clarity that was neither statistically nor clinically significant, with no adverse effects reported in this study. NCT05244525 (ClinicalTrials.gov).