Computational Fluid Dynamics Simulation Analysis Research Articles

Spreading model of single droplet impacting the banana leaf surface and computational fluid dynamics simulation analysis

The droplet deposition behavior is an important indicator of precision agriculture and sustainable agriculture 4.0. Comprehensive analysis of the behavior and modeling of pesticide droplets impacting target leaves is an important basis for achieving efficient spray deposition. In this study, banana leaves were taken as the research object, the spreading model and computational fluid dynamics (CFD) model of single droplet impacting on the target leaf surface were studied from the micro and macro perspectives. The aim is to clarify and obtain the quantitative mapping relationship between droplet deposition performance and related operating parameters. The results showed that the pesticide droplets were asymmetrically spread and slipped on the surface of the inclined banana leaves. The maximum lateral spreading diameter Dnmax was only affected by the normal component of Weber number Wen, while the maximum tangential spreading diameter Dtmax and slip distance L were affected by the normal component of Weber number Wen and the inclination angle α. As the impact velocity increases, the pesticide droplets interact with the non-smooth morphology of the banana leaf surface to form a large number of pinning sites on the edge contact line. Combining the microscopic characteristics of banana leaves with the physicochemical characteristics of the droplets, a CFD model was established to carry out single-drop impact simulation verification. The impact velocity and inclination angle were set as variables to carry out CFD simulation of the dynamic process. The numerical simulation results are consistent with the spreading model obtained from the experimental study, which can quantitatively reflect the impact process of pesticide droplets. The spreading model and CFD model of pesticide droplets impacting on the banana leaf surface established in this study, can provide guidance for the selection of pesticide application for the spray droplet deposition behavior. At the same time, it can also provide methodological reference for other crop spray research and spray technology research in other fields.

Make Way for the Wind—Promoting Urban Wind Corridor Planning by Integrating RS, GIS, and CFD in Urban Planning and Design to Mitigate the Heat Island Effect

Under the trend in climate change, global warming, and the increasingly serious urban heat island effect, promoting urban wind corridor planning to reduce urban temperature and mitigate the effect of urban heat islands has received widespread attention in many cities. With emerging awareness of the need to explicitly incorporate climate considerations into urban planning and design, integrating current spatial analysis and simulation tools to enhance urban wind corridor planning to obtain the best urban ventilation effect has become an increasingly important research topic in green city development. However, how to systematically carry out urban wind corridor planning by employing related technology and simulation tools is a topic that needs to be explored urgently in both theory and practice. Taking Zhumadian City in China as an example, this study proposes a method and planning approach that uses remote sensing (RS), geographic information system (GIS), and computational fluid dynamics (CFD) in an integrated way to understand urban landscape and to conduct urban wind corridor planning. The research results reveal that the urban form of Zhumadian City favors the development of urban wind corridors, and that the railway lines and some major roads in the city have the potential to be developed as the city’s main wind corridors. However, there are still ventilation barriers resulting from the existing land use model and building layout patterns that need to be adjusted. In terms of local-level analysis, the CFD simulation analysis also reveals that some common building layout patterns may result in environments with poor ventilation. Finally, based on the results of our empirical analysis and local planning environment, specific suggestions are provided on how to develop appropriate strategies for urban wind corridor planning and adjustments related to land use planning and building layout patterns in order to mitigate the impact of the urban heat island effect.

Comparison between CFD simulation and affinity laws and analysis of the degree of reaction.

Computational Fluid Dynamics (CFD) is a modern technology used to study fluid flow. Experimental methods for predicting the turbomachinery performance involve greater time consumption and financial resources compared to the CFD approach. For the centrifugal pump the impeller is the main component, as it transfers energy to the fluid. The pump flow rate and the total head are directly associated with the impeller rotation speed. The purpose of this paper is to present the analysis and comparison of numerical simulation results using Computational Fluid Dynamics of a centrifugal pump impeller under three different rotation speeds: 3500 rpm (nominal), 3100 rpm and 2700 rpm. The software used was ANSYS-CFX®, the turbulence model adopted was the Shear Stress Transport (SST). Eight operating points were simulated for each rotation. The simulation provided the characteristic curves, pressure distribution, and total and static pressure at the inlet and the outlet of the impeller. The degree of reaction was calculated. The results were compared by application of affinity laws, and showed agreement with them. The results also showed that the degree of reaction increased with increasing flow rate, and it was coherent with the backward curved blade impeller. The simulations show that the energy portions that make up the total energy transferred by the impeller agree with the affinity laws.

Computational fluid dynamics simulation analysis of the effect of curved rice leaves on the deposition behaviour of droplets

BackgroundAlthough previous studies on the droplet deposition behaviour of rice leaves have modelled the leaves as flat surface structures, their curved surface structures actually have a significant effect on droplet deposition.ResultsIn this paper, the statistical distribution of the coordinate parameters of rice leaves at the elongation stage was determined, computational fluid dynamics (CFD) simulation models of droplet impact on rice leaves with different curvature radii were built, and the effect of leaf curvature radius on the deposition behaviour and spreading diameter of droplets on rice leaves was studied using validated simulation models. The results showed that the average relative errors of the CFD simulation models were in the range of 2.23–9.63%. When the droplets struck the rice leaves at a speed of 4 m/s, the 50 μm droplets did not bounce within the curvature radii of 25–120 cm, the maximum spreading diameters of 200 and 500 μm droplets that just adhered to the leaves were 287 and 772 μm, respectively. The maximum spreading diameters of 50, 200, and 500 μm droplets that just split were 168, 636, and 1411 μm, respectively. As the curvature radii of the leaves increased, the maximum spreading diameter of the droplets gradually decreased, and droplet bouncing was more likely to occur. However, a special case in which no significant change in the maximum spreading diameter arose when 50 μm droplets hit a leaf with a curvature radius exceeding 50 cm.ConclusionSplitting generally occurred for large droplets with a small curvature radius and small tilt angle; bouncing generally occurred for large droplets with a large curvature radius and large tilt angle. When the droplet was small, the deposition behaviour was mostly adhesion. The change in spreading diameter after stabilisation was similar to the change in maximum spreading diameter, where the spreading diameter after stabilisation greatly increased after droplet splitting. This paper serves as a reference for the study of pesticide droplet deposition and its application in rice-plant protection.

Experimental and Computational Research on the Effect of Flow Distribution on the Growth of Boron Nitride Nanotubes by Chemical Vapor Deposition

The chemical vapor deposition (CVD) method offers a controlled and scalable approach for the large-scale production of boron nitride nanotubes (BNNTs). However, current research on BNNTs has been primarily focused on identifying precursors that can facilitate the efficient preparation of pure BNNTs. The collection of BNNTs remains a significant challenge due to the complex nature of the CVD reaction, which is influenced by the variable location of the floating aggregation of BNNTs generated from the gas phase reaction. To address this issue, we utilized B/MgO/Fe2O3, a well-established CVD precursor, to grow BNNTs in a horizontal furnace. Through experimental and computational fluid dynamics simulation analysis, we identified the impact of vortex generation and low flow rate on the floating height of BNNTs. Using the insights gained from these investigations, we designed a more efficient growth setup, laying the foundation for achieving larger-scale BNNT production in the future.

The Biomechanical Characteristics of Swallowing in Tracheostomized Patients with Aspiration following Acquired Brain Injury: A Cross-Sectional Study.

Investigate the biomechanical characteristics in tracheostomized patients with aspiration following acquired brain injury (ABI) and further explore the relationship between the biomechanical characteristics and aspiration. This is a single-center cross-sectional study. The tracheostomized patients with aspiration following ABI and age-matched healthy controls were recruited. The biomechanical characteristics, including velopharynx (VP) maximal pressure, tongue base (TB) maximal pressure, upper esophageal sphincter (UES) residual pressure, UES relaxation duration, and subglottic pressure, were examined by high-resolution manometry and computational fluid dynamics simulation analysis. The penetration-aspiration scale (PAS) score was evaluated by a videofluoroscopic swallowing study. Fifteen healthy subjects and fifteen tracheostomized patients with aspiration following ABI were included. The decreased VP maximal pressure, increased UES residual pressure, and shortened UES relaxation duration were found in the patient group compared with the control group (p < 0.05). Furthermore, the subglottic pressure significantly decreased in patients (p < 0.05), while no significant difference was found in TB maximal pressure between groups (p > 0.05). In addition, in the patient group, VP maximal pressure (rs = -0.439; p = 0.015), UES relaxation duration (rs = -0.532; p = 0.002), and the subglottic pressure (rs = -0.775; p < 0.001) were negatively correlated with the PAS score, while UES residual pressure (rs = 0.807; p < 0.001) was positively correlated with the PAS score (p < 0.05), the correlation between TB maximal pressure and PAS score (rs = -0.315; p = 0.090) did not reach statistical significance. The biomechanical characteristics in tracheostomized patients with aspiration following ABI might manifest as decreased VP maximal pressure and subglottic pressure, increased UES residual pressure, and shortened UES relaxation duration, in which VP maximal pressure, UES relaxation duration, subglottic pressure, and UES residual pressure were correlated with aspiration.

CFD simulation and sensitivity analysis of an industrial packed bed methanol synthesis reactor

The conversion of renewable hydrogen to methanol as energy carrier could be a key solution to reduce CO2 emissions from fossil fuels and deal with the climate change. In the present study a steady-state Computational Fluid Dynamics (CFD) model has been employed to simulate packed bed reactor for methanol production from natural gas to predict the behavior of gas streams in the tube side. The model consists of two-dimensional mass and heat transport equations accounting for axial and radial dispersion in the reactor tube. After validating the numerical results, the sensitivity analysis of various parameters such as reactor length, tube diameter, inflow temperature, shell temperature, operating pressure, flow rate and carbon source in the feed stream on the rate of methanol production of an industrial petrochemical plant have been studied. As can be seen in numerical results, some parameters such as shell temperature, operating pressure, flow rate and carbon source in the feed stream have a significant impact on methanol production while some other parameters such as tube length and tube diameter have little effect on methanol productivity. Numerical results indicate that by using the recommended parameters, methanol production increases about 1.6 times compared to the operating conditions of the plant.

Analysis and Research on No-Load Air Gap Magnetic Field and System Multiobjective Optimization of Interior PM Motor

In this article, considering the influence of iron core saturation and complex boundary conditions, a novel no-load magnetic field analytical method and system multiobjective optimization model for interior permanent magnet synchronous motor (IPMSM) are proposed. First, an analytical method based on magnetic potential permeance method is proposed. The complex cogging effect and equivalent air gap permeability function are fully considered in this method. Furthermore, on the basis of Taguchi optimization design based on Fuzzy theory, an improved optimization model considering multivariable interaction is proposed. Among them, in order to comprehensively consider the performance of electromagnetic, vibration, and temperature rise, five optimization objectives including torque, pulsation, cogging torque, loss, and flux density are optimized. The sensitivity of design variables and the interaction between variables are not ignored. Finally, a 6-pole 36-slot IPMSM is manufactured for prototype experiments. A large number of prototype experiments, finite element, and computational fluid dynamics simulation analysis including no-load magnetic field, back electromotive force, temperature rise, electromagnetic torque, and so on are carried out. The accuracy and rationality of the proposed no-load magnetic field analysis method and global optimization model are well-verified.

Biomechanical mechanism of reduced aspiration by the Passy-Muir valve in tracheostomized patients following acquired brain injury: Evidences from subglottic pressure.

Aspiration is a common complication after tracheostomy in patients with acquired brain injury (ABI), resulting from impaired swallowing function, and which may lead to aspiration pneumonia. The Passy-Muir Tracheostomy and Ventilator Swallowing and Speaking Valve (PMV) has been used to enable voice and reduce aspiration; however, its mechanism is unclear. This study aimed to investigate the mechanisms underlying the beneficial effects of PMV intervention on the prevention of aspiration. A randomized, single-blinded, controlled study was designed in which 20 tracheostomized patients with aspiration following ABI were recruited and randomized into the PMV intervention and non-PMV intervention groups. Before and after the intervention, swallowing biomechanical characteristics were examined using video fluoroscopic swallowing study (VFSS) and high-resolution manometry (HRM). A three-dimensional (3D) upper airway anatomical reconstruction was made based on computed tomography scan data, followed by computational fluid dynamics (CFD) simulation analysis to detect subglottic pressure. The results showed that compared with the non-PMV intervention group, the velopharynx maximal pressure (VP-Max) and upper esophageal sphincter relaxation duration (UES-RD) increased significantly (P < 0.05), while the Penetration-Aspiration Scale (PAS) score decreased in the PMV intervention group (P < 0.05). Additionally, the subglottic pressure was successfully detected by CFD simulation analysis, and increased significantly after 2 weeks in the PMV intervention group compared to the non-PMV intervention group (P < 0.001), indicating that the subglottic pressure could be remodeled through PMV intervention. Our findings demonstrated that PMV could improve VP-Max, UES-RD, and reduce aspiration in tracheostomized patients, and the putative mechanism may involve the subglottic pressure. [http://www.chictr.org.cn], identifier [ChiCTR1800018686].

Investigations on Temperatures of the Flat Insert Mold Cavity Using VCRHCS with CFD Simulation.

This paper adopted transient CFD (Computational Fluid Dynamics) simulation analysis with an experimental method for designing and surveying the quick and uniform rise in the temperature of the plastics into the insert mold cavity. Plastic injection molding utilizing VCRHCS (Vapor Chamber for Rapid Heating and Cooling System) favorably decreased the defects of crystalline plastic goods’ welding lines, enhancing the tensile intensity and lowering the weakness of welding lines of a plastic matter. The vapor chamber (VC) possessed a rapid uniform temperature identity, which was embedded between the heating unit and the mold cavity. The results show that the tensile strength of the plastic specimen increased above 8%, and the depths of the welding line (V-gap) decreased by 24 times (from 12 μm to 0.5 μm). The VCRHCS plastic injection molding procedure can constructively diminish the development time for novel related products, as described in this paper.

Tailorable 3DP Flexible Scaffolds with Porosification of Filaments Facilitate Cell Ingrowth and Biomineralized Deposition.

Facilitating cell ingrowth and biomineralized deposition inside filaments of 3DP scaffolds are an ideal bone repair strategy. Here, 3D printed PLGA/HA scaffolds with hydroxyapatite content of 50% (P5H5) and 70% (P3H7) were prepared by optimizing 3D printing inks, which exhibited good tailorability and foldability to meet clinical maneuverability. The supercritical CO2 foaming technology further endowed the filaments of P5H5 with a richer interconnected pore structure (P5H5-C). The finite element and computational fluid dynamics simulation analysis indicated that the porosification could effectively reduce the stress concentration at the filament junction and improved the overall permeability of the scaffold. The results of in vitro experiments confirmed that P5H5-C promoted the adsorption of proteins on the surface and inside of filaments, accelerated the release of Ca and P ions, and significantly upregulated osteogenesis (Col I, ALP, and OPN)- and angiogenesis (VEGF)-related gene expression. Subcutaneous ectopic osteogenesis experiments in nude mice further verified that P5H5-C facilitated cell growth inside filaments and biomineralized deposition, as well as significantly upregulated the expression of osteogenesis- and angiogenesis-related genes (Col I, ALP, OCN, and VEGF) and protein secretion (ALP, RUNX2, and VEGF). The porosification of filaments by supercritical CO2 foaming provided a new strategy for accelerating osteogenesis of 3DP implants.

Internal flow field analysis of heterogeneous porous scaffold for bone tissue engineering

The internal pore structure of the porous scaffold for bone tissue engineering and the pressure and velocity distributions of its flow field affect the attachment, proliferation and differentiation of osteoblasts. The permeability of the porous scaffold determines its ability to transport cellular nutrients and metabolites. Therefore, studying the fluid flow characteristics of the porous scaffold plays a vital role in its biological applications. Heterogeneous porous scaffolds (HPS) with irregular internal pore structure have more bionic characteristics of natural structure than uniform porous scaffolds with regular internal pore structure. In order to comprehensively grasp the biological properties of HPS, this article designed HPS with different porosities based on the Voronoi generation method and random theory, and then used computational fluid dynamics (CFD)software to conduct fluid flow simulations. The velocity and pressure distribution rules of the internal flow field of HPS with different porosities were obtained by CFD simulation analysis, and the relationship between the porosity and the distribution rules was studied. Furthermore, the permeabilities of HPS with different porosities were calculated based on Darcy's law, and the influence rule of porosity on the permeability was obtained.

The Influence of Wind Effects on Architectural Buildings Heights in Iraqi Residential Buildings Based on Computational Fluid Dynamics Simulations

The gradient of height in buildings is the most common way to prepare a comfortable environment and to increase wind forces around the buildings. This study assessed various design choices that enable architectural buildings to have different heights using computational fluid dynamics (CFD) simulation to analyse wind conditions. Nonetheless, wind effects may create uncomfortable zones around high buildings and may be hazardous for pedestrians in open spaces. As such, this study looked into pedestrian level wind (PLW) to enhance the wind environment of buildings in Iraqi climate. Wind characteristics may create a range of disturbance levels that affect pedestrian areas. Iraqi residential buildings were taken as case study to quantitatively analyse the outdoor buildings at PLW, so as to generate some ideas and solutions between CFD simulation analysis and architectural design to yield an optimal model.

Detection of two-point leakages in a pipeline based on lab investigation and numerical simulation

The pipeline is an efficient tool to transmit fluid in a long distance. However, due to different reasons such as pipe aging or natural disaster, multiple leaks can occur to the broken pipeline system. Therefore, it is very crucial to find an accurate, quick, and low-cost method to detect the leakages in the pipeline. In this study, pressure distribution analysis was proposed to diagnose the location of the leakages via experimental study and Computational Fluid Dynamics (CFD) simulation. Different dimensionless variables, which are the dimensionless leak location, dimensionless leak rate, and dimensionless pressure drop, were applied in our analysis. Through the mathematical modeling which was built on the dimensionless variables, the locations of the leakages can be detected. Multiple flowrate testing was conducted to detect the locations of two leakages. The proposed method can be used to monitor the severity of the pipeline during the operation. Different from former researchers, our work combined the experimental study, CFD simulation, and dimensionless variable analysis to solve the problem of two-point leak detection. This new method can be applied to detect the leakages under different flow rates. For the detection of multiple leaks, a trial-and-error approach was investigated. When the pressure and flow rate at the inlet and outlet of the leaking pipe are known, not only does the method supply an inexpensive way to identify the leaks but also it shortens the time interval between an accident occurring and finding the leak points.

Characterization of the Solid Particle Erosion of the Sealing Surface Materials of a Ball Valve

The ball valve is an essential piece of equipment in an oil and gas pipeline. The sand particles transported through the pipeline can cause erosion and wear to the ball valve, thus causing it to fail, leading to serious safety hazards. In this paper, the self-designed erosion experiment method was combined with computational fluid dynamics (CFD), while the Euler-Lagrange method was also introduced to optimize the Oka erosion model and Ford particle-wall rebound model. The erosion mechanism and characteristics of the ball valve sealing surface in gas-solid two-phase flow were simulated, while the erosion condition of the specimen was analyzed and compared when exposed to different factors, such as different particle velocities, impact angle, particle size, and specimen materials. The experimental data conformed well to the CFD erosion simulation data, verifying the accuracy of the CFD simulation analysis. The results indicated that the worn surface was caused by various wear mechanisms, while a “stagnation zone” was identified at the center of the specimen. The maximum erosion area, which was U-shaped, was also located at the center. The erosion rate increased in conjunction with an increase in the particle velocity and size, both of which failed to affect the erosion pattern. The erosion rate initially increased, after which it decreased with the impact angle, reaching the maximum value at an impact angle of 30°. This paper summarizes the erosion failure mechanism and characteristics in gas–solid two-phase flow and provides both technical support and a theoretical basis for the on-site maintenance of essential vulnerable parts in the pipeline, such as ball valves.

CFD Simulation Analysis on Make-up Air Supply by Distance from Cookstove for Cooking-Generated Particle.

Indoor cooking is the main cause of particulate matter (PM) within residential houses along with smoking. Even with the range hood turned on, cooking-generated PM can spread quickly into the living room due to the heat generated by the cookstove. In order to improve the PM spread prevention performance of the range hood, a supply of make-up air is needed. Generally, make-up air is supplied through a linear diffuser between the kitchen and living room. In such cases, it is necessary to determine the appropriate location of the supply diffuser. This study evaluates the spread of PM according to different locations of the supply diffuser, which feeds in make-up air. For this purpose, indoor airflow and PM spread were analyzed through CFD (Computational Fluid Dynamics) simulation analysis. By changing the location of the supply diffuser from the contaminant source, PM concentration was analyzed in the kitchen and living room of an apartment house in Korea. Based on the results, the optimal installation location was determined. In this study, 1.5 m from the source was the most effective location of make-up air supply to prevent the spread of cooking-generated particles.

Experimental and computational investigation of engine characteristics in a compression ignition engine using mahua oil

Many research works have been carried out worldwide for finding a suitable substitute for diesel which is predominantly used for Heavy Vehicles, and creating a validated numerical model which will be useful for effective performance predictions. A lot of experimental work has been carried out using Pure Mahua oil as an alternative to diesel. But an extensive numerical analysis for the same has not been carried out so far. In this research, combustion and emission characteristics of pure Mahua oil as an alternative to diesel running at 40%, 80% and 100% load has been carried out experimentally and theoretically using Computational Fluid Dynamics software ANSYS Fluent ICE. An extensive CFD simulation analysis was carried out using the dimensions of the Compression Ignition engine used for the experiment by considering a cylindrical domain in which a 60 degrees Sector of combustion chamber taken for analysis. Transient Computational Fluid Dynamics (CFD) analysis has been carried out by using injection profile and other engine data as input for the combustion simulation. The simulated combustion parameters that were considered for interpretation includes the Pressure-Crank Angle (P-ϴ), Temperature Crank Angle (T-ϴ) and Apparent heat release rate. The experimental and simulation results presented in this article justifies Mahua Oil as a potential alternative for Diesel. From this research work we conclude that though the combustion and performance characteristics of Mahua Oil is less compared to that of Diesel, the lesser Nox emissions and cost of the fuel makes it as an attractive alternative for diesel.

CFD simulation of mass transfer in electrochemical reactor with mesh cathode for higher phenol degradation

Cathode, where electro-catalytic oxidation barely took place, could exert a significant influence on electro-catalytic efficiency, whereas little investigation has been focused on this effect. In this study, the effect of cathode configuration on electro-catalytic activities was investigated with phenol as model pollutant, and the mechanism was revealed from the perspective of mass transfer with computational fluid dynamics (CFD) simulation. Compared with the planar Ti cathode, the electro-catalytic reactor with mesh Ti exhibited 1.21–1.26 times faster phenol degradation rate under various testing inlet flow rates. CFD simulation revealed the higher velocity distribution both in the reactor and on anode surface when meshed Ti cathode was used, which benefited faster fluid flow so that the pollutant transfer was accelerate especially at higher inlet flow rate. Excellent agreement of mass transfer between CFD simulation and experimental analysis was achieved, the mass transfer coefficient with mesh Ti was 1.40–1.55 times of the case with planar cathode under various inlet flow rates. The enhanced mass transfer performance was mainly ascribed to the rhombic pores of mesh cathode where hydrogen bubbles generated on would escape timely and randomly at various directions, leading to the disturbance of fluid flow around the anode. This study highlighted mesh cathode played a key role in improving pollutant degradation, and CFD, as a versatile and convenient tool to analyze the hydrodynamic behavior of electro-catalytic reactor, showed a strong persuasion to guide the optimization of electrode configuration.

Design and tests of a non-contact Bernoulli gripper for rough-surfaced and fragile objects gripping

PurposeVaried shapes and sizes of different products with irregular rough surface and fragile properties give a challenge to traditional contact gripping. Single Bernoulli grippers are not suited to handle fragile objects as the impact of center negative pressure force could result in large deformation and stress which damage the materials, and they are also have some limitations for gripping objects with different large and small shapes. Thus, this paper aims to design a non-contact gripper for soft, rough-surfaced and fragile objects gripping with multi Bernoulli heads, which have optimal structures and parameters.Design/methodology/approachThe compressed air is ejected into four Bernoulli heads through radial and long flow channels, then passes through four strip-shaped narrow gaps after fully developing in the annular cavity to provide negative pressure. Based on the mathematic model and the computational model, the key structural parameters affecting the gripping performance are selected, and parameters optimization of the gripper is performed by computational fluid dynamics simulation analysis and performance evaluation. The orthogonal method is used and L16 orthogonal array is selected for experimental design and optimization. The characteristics of the designed gripper are tested from the aspects of pressure distribution and lifting force.FindingsFrom the applications in gripping different objects, the designed non-contact gripper can grip varied shapes and sizes of soft, rough-surfaced, fragile and sliced objects with little effect of torque.Originality/valueIn this paper, a non-contact gripper is designed for handling soft, rough-surfaced and fragile objects based on the Bernoulli principle. A systematic approach, which consists of modeling, simulation, optimization and measurement is provided for the non-contact gripper design and tests.

Hemolysis associated with Impella heart pump positioning: In vitro hemolysis testing and computational fluid dynamics modeling.

Short-term mechanical circulatory support devices provide temporary hemodynamic support in heart failure and are increasingly used to enable recovery or as a bridge to decision. Blood damage with mechanical circulatory support devices is influenced by many factors, including the magnitude and duration of shear stress and obstruction to blood flow. This study aimed to evaluate the effects of the Impella CP® heart pump positioning on hemolysis using in vitro hemolysis testing and computational fluid dynamics modeling. The in vitro hemolysis testing was conducted per the recommended Food and Drug Administration and American Society for Testing and Materials guidelines. The bench hemolysis testing and computational fluid dynamics simulation analysis were performed for both normal operating (outlet unobstructed) and outlet-obstructed condition of Impella CP (mimicking outlet on the aortic valve due to improper positioning). The modified index of hemolysis was 2.78 ± 0.69 at normal operating conditions compared to 18.7 ± 7.8 when the Impella CP outlet was obstructed (p = 0.002). Computational fluid dynamics modeling showed about three times increase in exposure time to regions of high shear stress when the Impella CP outlet was obstructed compared to unobstructed condition, thus supporting the experimental observations. Based on these results, it is recommended to ensure proper placement of Impella CP via regular monitoring using echocardiographic guidance or other methods to minimize the risk of hemolysis associated with an obstructed outflow.