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In vitro experiment and computational fluid dynamics simulation study on blood pump for total cavopulmonary connection circulation

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FRONTIERS IN BIOENGINEERING AND BIOTECHNOLOGY 2025年 13卷 1564426页

作者： Wu, Yong Chen, Tong Cai, Yunhan Wang, Shengzhang Lu, Haiyan Fudan Univ Ctr Biotechnol & Biomed Engn Yiwu Res Inst Yiwu Zhejiang Peoples R China Fudan Univ Inst Biomed Engn Technol Acad Engn & Technol Shanghai Peoples R China Fudan Univ Inst Biomech Dept Aeronaut & Astronaut Shanghai Peoples R China Tongji Univ Shanghai East Hosp Dept Ultrasound Sch Med Shanghai Peoples R China

Objective This study aimed to address the compromised hemodynamics in patients with total cavopulmonary connection circulation after Fontan surgery. While the Fontan procedure effectively separates systemic and pulmonary venous blood, resolving organ hypoxia, patients often experience complications such as elevated central venous pressure and reduced pulmonary artery pressure (Fontan failure) due to insufficient circulatory support. To improve this, a right ventricular assist device with a flexible impeller was designed. This study investigated the impeller's characteristics through in vitro experiments and computational fluid dynamics (CFD) simulations, validating the accuracy and effectiveness of the CFD simulation *** The study employed in vitro hydraulic experiments and particle image velocimetry (PIV) to test the hydraulic performance and flow field of the blood pump. Simultaneously, a simulation model was established, and CFD simulations were performed. By quantitatively comparing simulation and experimental results, pulmonary artery blood flow, increased central venous pressure, and the velocity field in the mid-plane of the left pulmonary artery during impeller rotation were evaluated. The experimental setup was designed to mimic physiological dimensions, ensuring consistency with real-world *** The results demonstrated that the simulation method accurately predicted the trends of various indicators, with maximum errors within acceptable limits. Specifically, the relative error between simulation and experiment for pulmonary artery outflow was a maximum of 1.65%. The relative error for elevated central venous pressure was small, except for a few points. The simulation results of the velocity field also accurately reflected the main characteristics observed in the *** This study validated the potential of the designed impeller in improving hemodynamics in patients after Fontan surgery through in vitro experiments

关键词： total cavopulmonary connection right heart assist device impeller in vitro experiment computational fluid dynamics simulation

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computational fluid dynamics simulation and experimental analysis of ultrafine powder suspension

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Rare Metals 2020年第7期39卷 850-860页

作者： Wang-Chao Wu Jian Cui Hao Jiang Hai-Bo Jiang Chun-Zhong Li School of Materials Science and Engineering East China University of Science and TechnologyShanghai 200237China

The suspension characteristics of ultrafine powder slurry in the stirred vessel were simulated by using computational fluid *** results show that the Rushton disk turbine impeller is more conducive to maintaining suspended homogeneity and circulation of slurry compared with the pitch blade turbine pumping up impeller and the pitch blade turbine pumping down *** the increase in stirring speed enhances turbulent fluctuation and anisotropic velocity of the fluid at the cost of more power consumption,which improves dispersibility and suspensibility of the ***,the change of impeller clearance has a weak influence on the flow pattern,and the impeller clearance of 0.32T(T is the diameter of the bottom of the reactor)can achieve better dispersivity and suspensibility of the particles with lower power consumption and larger axial *** experiments of surface coating modification of ultrafine titanium dioxide(TiO2)were carried out under the same conditions for those of the simulation *** surface film morphology and photocatalytic properties of the modified TiO2 were analyzed,and the obtained data are well consistent with the simulation results.

关键词： computational fluid dynamics simulation Ultrafine powder slurry Suspension quality Impeller type Stirring speed Impeller clearance

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Multiphase computational fluid dynamics simulation of Ignition Overpressure and Plume-Water Interaction in the SLS Scale Model Acoustics Test

Multiphase Computational Fluid Dynamics Simulation of Igniti...

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AIAA SciTech Forum

作者： Soto, John E. Williams, Brandon R. NASA Jacobs Space Explorat Grp Marshall Space Flight Ctr Huntsville AL 35808 USA NASA Marshall Space Flight Ctr Huntsville AL USA

ISBN: (数字)9781624107115

ISBN: (纸本)9781624107115

The solid rocket boosters (SRBs) on the Space Launch System (SLS) generate powerful ignition overpressure (IOP) waves that can potentially damage the vehicle and surrounding ground structures. Based on historical Shuttle experience, the IOP will be mitigated by utilizing an IOP/Sound Suppression (SS) water system which sprays water in and around the SRB and RS-25 engine plumes. However, the complex multiphase physics of the resulting plume-water interaction can lead to undesirable effects, such as high velocity water spray onto the engine nozzles and SRB nozzle side loads. Prior to launch, insight into this environment can be achieved through scale model testing and predictive computational fluid dynamics (CFD) modeling. The Scale Model Acoustic Test (SMAT) was conducted at Marshall Space Flight Center to provide the data necessary to develop the SLS liftoff acoustic environments by using a 5% scale SLS vehicle, fully integrated with a scaled IOP/SS water system, mobile launcher (ML), and tower. NASA engineers have put forth significant effort in validating the Loci/CHEM-Real fluids multiphase CFD solver on a wet hold down test from the SMAT series. In this paper, the IOP acoustics and plume-water interactions predicted by the CFD model are compared and validated against the experiment, enabling relatively inexpensive, rapid turnaround for multiphase launch environment analyses to support future flights and design evolutions of SLS and other launch vehicles.

关键词： Acoustic Phenomena computational fluid dynamics simulation Solid Rocket Boosters Launch Vehicles NASA Marshall Space Flight Center Ignition Transients Pressure Probes Propellant Combustion Reynolds Averaged Navier Stokes

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Pressure drop across membrane spacer-filled channels using porous media characteristics and computational fluid dynamics simulation

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DESALINATION AND WATER TREATMENT 2022年 247卷 28-39页

作者： Abdelkader, Bassel A. Sharqawy, Mostafa H. Univ Guelph Coll Engn & Phys Sci Sch Engn 50 Stone Rd E Guelph ON N1G 2W1 Canada

The presence of spacers in membrane modules generates turbulence which enhances the mass transfer through the membrane. However, spacers increase the pressure drop in the flow channels which increases the operating cost. Previous approaches used empirical correlations to estimate the pressure drop across spacer-filled channels in membrane modules. In this study, a different approach is proposed for accurate pressure drop prediction by treating the spacer as a porous media and using Darcy-Forchheimer's model for flow in porous media. The pressure drop is predicted using Darcy-Forchheimer's model and computational fluid dynamics simulation which is validated using experimental data available in the literature. This study focuses on the effect of spacer filament diameter and porosity on the permeability coefficient, and pressure drop. The critical Reynolds number is calculated to identify the transition between Darcy and non-Darcy flow through the spacer-filled channels. It is found that the permeability coefficient increases with the spacer filament diameter and porosity. This study also proposes a correlation to calculate the permeability coefficient based on the spacer porosity and filament diameter.

关键词： Membrane spacer Pressure drop Porous media computational fluid dynamics simulation

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computational fluid dynamics simulation OF FLOW OF EXHALED PARTICLES FROM POWERED-AIR PURIFYING RESPIRATORS

COMPUTATIONAL FLUID DYNAMICS SIMULATION OF FLOW OF EXHALED P...

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ASME International Design Engineering Technical Conferences / Computers and Information in Engineering Conference

作者： Xu, Susan S. Lei, Zhipeng Zhuang, Ziqing Bergman, Michael Ctr Dis Control & Prevent Natl Inst Occupat Safety & Hlth Pittsburgh PA USA

ISBN: (纸本)9780791859179

In surgical settings, infectious particulate wound contamination is a recognized cause of post-operative infections. Powered air-purifying respirators (PAPRs) are widely used by healthcare workers personal protection against infectious aerosols. Healthcare infection preventionists have expressed concern about the possibility that infectious particles expelled from PAPR exhalation channels could lead to healthcare associated infections, especially in operative settings where sterile procedural technique is emphasized. This study used computational fluid dynamics (CFD) modeling to simulate and visualize the distribution of particles exhaled by the PAPR wearer. In CFD simulations, the outward release of the exhaled particles, i.e., ratio of exhaled particle concentration outside the PAPR to that of inside the PAPR, was determined. This study also evaluated the effect of particle sizes, supplied air flow rates, and breathing work rates on outward leakage. This simulation study for the headform and loose-fitting PAPR system included the following four main steps: (1) preprocessing (establishing a geometrical model of a headform wearing a loose-fitting PAPR by capturing a 3D image), (2) defining a mathematical model for the headform and PAPR system, and (3) running a total 24 simulations with four particle sizes, three breathing workloads and two supplied-air flow rates (4x3x2=24) applied on the digital model of the headform and PAPR system, and (4) post-processing the simulation results to visually display the distribution of exhaled particles inside the PAPR and determine the particle concentration of outside the PAPR compared with the concentration inside. We assume that there was no ambient particle, and only exhaled particles existed. The results showed that the ratio of the exhaled particle concentration outside to inside the PAPR were influenced by exhaled particle sizes, breathing workloads, and supplied-air flow rates. We found that outward concentration leakage

关键词： Exhaled particles outward leakage powered air-purifying respirators computational fluid dynamics simulation Surgical setting

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computational fluid dynamics simulation of full breathing cycle for aerosol deposition in trachea: Effect of breathing frequency

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JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS 2019年 97卷 66-79页

作者： Piemjaiswang, Ratchanon Shiratori, Shuichi Chaiwatanarat, Tawatchai Piumsomboon, Pornpote Chalermsinsuwan, Benjapon Chulalongkorn Univ Fac Sci Dept Chem Technol 254 Phyathai Rd Bangkok 10330 Thailand Chulalongkorn Univ Dept Radiol Fac Med 254 Phyathai Rd Bangkok 10330 Thailand Chulalongkorn Univ Ctr Excellence Petrochem & Mat Technol 254 Phyathai Rd Bangkok 10330 Thailand Chulalongkorn Univ Adv Computat Fluid Dynam Res Unit 254 Phyathai Rd Bangkok 10330 Thailand

Aerosols have been widely used in the treatment of certain airway diseases. With different breathing conditions of patients, the flow pattern might not cause the aerosol to transport and deposit on the desired bronchial section. In this study, computational fluid dynamics simulations based on the Euler-Euler method were successfully used to evaluate the airflow behavior when an electrostatic charge was present. The three-dimensional domain was acquired and derived from the computed tomography scan of the patient. Three breathing frequencies were investigated. The instantaneous contour plot revealed that the particles migrated to the wall since charged particles will move from the high to the low potentials. It was found that the variation of the breathing frequency plays a significant role on designated particle deposition region. At a short flow time, the particles only traveled and deposited on the upper part of the airway, whereas as the time flow increased the particles tended to increasingly accumulate on the lower parts of the airway. The electrostatic charge model for aerosol deposition has shown that the further design of aerosol transport must take an average breathing frequency into consideration. The wall shear stress, oscillatory flow velocity index, granular temperature, granular pressure and skin friction coefficient were able to imply the amount of solid particles deposited within the system. All the purposed indices can be used as preliminary indicators for indicating a potential deposition location of the aerosol. (C) 2019 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

关键词： Aerosol deposition Breathing frequency computational fluid dynamics simulation Electrostatic charge Trachea Wall shear stress

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Quantification of computational fluid dynamics simulation assists the evaluation of protection by Gypenosides in a zebrafish pain model

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PHYSIOLOGY & BEHAVIOR 2021年第0期229卷 113223-113223页

作者： Zhao, Zhenkai Xiao, Qing Tchivelekete, Gabriel Mbuta Reilly, James Jiang, Huirong Shu, Xinhua Univ Strathclyde Dept Naval Architecture Ocean & Marine Engn Glasgow G4 0LZ Lanark Scotland Glasgow Caledonian Univ Dept Biol & Biomed Sci Glasgow G4 0BA Lanark Scotland Strathclyde Inst Pharm & Biomed Sci Glasgow G4 0RE Lanark Scotland Glasgow Caledonian Univ Dept Vis Sci Glasgow G4 0BA Lanark Scotland Shaoyang Univ Sch Basic Med Sci Shaoyang 422000 Hunan Peoples R China

In recent years, due to its rapid reproduction rate and the similarity of its genetic structure to that of human, the zebrafish has been widely used as a pain model to study chemical influences on behavior. Swimming behaviors are mediated by motoneurons in the spinal cord that drive muscle contractions, therefore a knowledge of internal muscle mechanics can assist the understanding of the effects of drugs on swimming activity. To demonstrate that the technique used in our study can supplement biological observations by quantifying the contribution of muscle effects to altered swimming behaviours, we have evaluated the pain/damage caused by 0.1% acetic acid to the muscle of 5 dpf zebrafish larvae and the effect of protection from this pain/damage with the saponin Gypenosides (GYP) extracted from Gynostemma pentaphyllum. We have quantified the parameters related to muscle such as muscle power and the resultant hydrodynamic force, proving that GYP could alleviate the detrimental effect of acetic acid on zebrafish larvae, in the form of alleviation from swimming debility, and that the muscle status could be quantified to represent the degree of muscle damage due to the acetic acid and the recovery due to GYP. We have also linked the behavioral changes to alteration of antioxidant and inflammation gene expression. The above results provide novel insights into the reasons for pain-related behavioral changes in fish larvae, especially from an internal muscle perspective, and have quantified these changes to help understand the protection of swimming behaviors and internal muscle by GYP from acetic acid-induced damage.

关键词： computational fluid dynamics simulation Hydrodynamic performance Gypenosides Acetic acid Zebrafish

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computational fluid dynamics simulation of system hydrodynamics in a riser of stage circulating fluidized bed reactor

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ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING 2019年第1期14卷 e2277-e2277页

作者： Phupanit, Jakkrapong Soanuch, Chaiwat Korkerd, Krittin Piumsomboon, Pornpote Chalermsinsuwan, Benjapon Chulalongkorn Univ Fac Sci Program Petrochem & Polymer Sci Bangkok Thailand Chulalongkorn Univ Fac Sci Dept Chem Technol Fuels Res Ctr 254 Phayathai Rd Bangkok 10330 Thailand Chulalongkorn Univ Ctr Excellence Petrochem & Mat Technol Bangkok Thailand Chulalongkorn Univ Adv Computat Fluid Dynam Res Unit Bangkok Thailand

The riser of conventional and stage circulating fluidized bed reactors were simulated using computational fluid dynamics. The objective was to examine the design parameter effects using a 2(3) statistical experimental design method. The results showed that number of reactor stages had the highest effect on the standard deviation of the solid volume fraction (SVF), the average SVF, and standard deviation of gas temperature in a horizontal direction. In addition, the reactor wall temperature had the highest effect on the average holding time of catalysts. Increasing the number of reactor stages could reduce the back-mixing and increase the system turbulence. The average vertical and horizontal solid particle velocities in the reactor stage region were higher than in the other regions. At the reactor stage region, peaks in the gas temperature were observed. The advantages of a stage reactor were confirmed to be applied in all the operating condition cases, independent of the solid particle mass flux.

关键词： computational fluid dynamics simulation stage circulating fluidized bed reactor statistical experimental design system hydrodynamics system mixing

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computational fluid dynamics simulation of breathing zone of the human for air quality with a personalized air curtain

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ADVANCES IN MECHANICAL ENGINEERING 2019年第5期11卷 155页

作者： Alshitawi, Mohammed Saleh Suyambazhahan, S. Alaboodi, Abdulaziz S. Qassim Univ Coll Engn Dept Mech Engn Buraydah Saudi Arabia Anna Univ Dept Mech Engn Dhanalakshmi Coll Engn Chennai 600025 Tamil Nadu India

In this article, the air quality is maintained in the breathing zone of a human using personalized air curtain. The breathing zone is modeled and simulated with ANSYS-Fluent 18.1 software and predicted the thermo-fluids flow characteristics in the breathing zone. The clean air is supplied from the air curtain device to distribute in the breathing zone of a human. There are 11 nozzles created in the front portion of the air curtain device to supply clean air in front of the face of the human. The air curtain provides a sealed cover between the pollutant and face, which protects the inward flow of pollutants. The flow becomes turbulent even at low Reynolds numbers 136-686 due to the mixing of air jets from multi-nozzles in the air curtain device and entrainment of ambient air into the breathing zone. The thermal balance (comfort) between breathing zone and atmosphere was maintained using isothermal air jets. The standard k-epsilon model is used for predicting the turbulent characteristics of air flow. The results obtained from the simulation was analyzed for optimum airflow velocity to occupy the breathing zone with clean air completely. The best flow pattern is achieved for the optimum nozzle exit velocity of 3 m/s, height y = 70 mm from the bottom of breathing zone for nozzle width of 2 mm. These conditions ensured the air quality and the comfort velocity (0.5 to 0.8 m/s) and pressure about 1 bar in the breathing zone.

关键词： Air quality air curtain ANSYS-Fluent computational fluid dynamics simulation turbulent model

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Numerical prediction of the performance of marine propellers using computational fluid dynamics simulation with transition-sensitive turbulence model

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART M-JOURNAL OF ENGINEERING FOR THE MARITIME ENVIRONMENT 2019年第2期233卷 515-527页

作者： Helal, Mohamed M. Ahmed, Tamer M. Banawan, Adel A. Kotb, Mohamed A. VSE Corp Alexandria Egypt Alexandria Univ Fac Engn Dept Naval Architecture & Marine Engn Alexandria Egypt Arab Acad Sci Technol & Maritime Transport Coll Engn & Technol Dept Marine Engn Alexandria Egypt

Determining and understanding the performance characteristics of marine propellers by experiments is quite a complex and costly task. Numerical predictions using computational fluid dynamics simulations could be a valuable alternative provided that the laminar-to-turbulent transition flow effects are fundamentally understood with the suitable numerical models developed. Experience suggests that the use of classical turbulent flow models may lead to high discrepancies especially at low rotational speeds where the effects of fluid flow transition from the laminar to the turbulent state may influence the predicted propeller's performance. This article proposes a complete and detailed procedure for the computational fluid dynamics simulation of non-cavitating flow over marine propellers using the "k-kl-omega" transition-sensitive turbulence model. Results are evaluated by "ANSYS FLUENT 16" for the "INSEAN E779A" propeller. Comparisons against the fully turbulent standard "k-epsilon" model and against experiments show improved agreement in way of flow transition zones at lower rotational speeds, that is, at low Reynolds numbers.

关键词： computational fluid dynamics simulation marine propellers performance characteristics ANSYS FLUENT transition-sensitive turbulence models fully turbulent models

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