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Journal of Hydrodynamics 2017年第2期29卷 361-375页

作者：张德胜施卫东张光建陈健 B.P.M.(bart)van Esch Research Center of Fluid Machinery Engineering and Technology Jiangsu UniversityZhenjiang 212013China Department of Mechanical Engineering Eindhoven University of TechnologyEindhoven 5600MBTheNetherlands

The cavitation shedding flow around a 3-D Clark-Y hydrofoil is simulated by using an improved filter-based model （FBM） and a mass transfer cavitation model with the consideration of the maximum density ratio effect between the liquid and the vapor. The unsteady cloud cavity shedding features around the Clark-Y hydrofoil are accurately captured based on an improved FBM model and a suitable maximum density ratio. Numerical results show that the predicted cavitation patterns and evolutions compare well with the experimental visualizations, and the prediction errors of the time-averaged lift coefficient, drag coefficient and Strouhal number St for the cavitation number o- = 0.8, the angle of attack a= 8°at a Reynolds number Re = 7 x 10^5 are only 3.29%, 2.36% and 9.58%, respectively. It is observed that the cavitation shedding flow patterns are closely associated with the vortex structures identified by the Q- criterion method. The predicted cloud cavitation shedding flow shows clearly three typical stages：（1） Initiation of the attached sheet cavity, the growth toward the trailing edge. （2） The formation and development of the re-entrant jet flow. （3） Large scale cloud cavity sheds downstream. Numerical results also indicate that the non-uniform adverse pressure gradient is the main driving force of the re-entrant jet, which results in the U-shaped cavity and the 3-D bubbly structure during the cloud cavity shedding.

关键词： Cloud cavitation shedding flow filter-based model turbulent viscosity Clark-Y hydrofoil

Numerical investigation on the mechanism of impeller hub corner separation flow and induced energy loss in the bulb tubular pump

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Journal of Hydrodynamics 2023年第2期35卷 252-267页

作者： Long-yue Sun Qiang Pan De-sheng Zhang Rui-jie Zhao B.P.M.(bart)van Esch Research Center of Fluid Machinery Engineering and Technology Jiangsu UniversityZhenjiang212013China Wenling Fluid Machinery Technology Institute of Jiangsu University Wenling317525China Department of Mechanical Engineering Eindhoven University of TechnologyEindhovenThe Netherlands Shimge Pump Industry(Zhejiang)Co. Ltd.Wenling317525China

Impeller hub corner separation flow(IHCS)has a significant influence on energy conversion of the bulb tubular pump,and its unsteady characteristics are investigated with CFD-based *** generation mechanism and power loss characteristics of IHCS are investigated by the entropy production method and pressure fluctuation *** main cause can be attributed to the large transverse pressure gradient near the hub at the trailing edge of the impeller,which is aggravated by the circumferential movement trend and the diffuser reverse flow,while the IHCS is significantly weakened with increased flow *** undesirable flow behavior is more likely to cause a significant increase in energy loss near the hub region compared to that in the rim *** relative vortex stretching induced by the velocity gradient is the main cause of the horn-like vortex(HLV),and its intensity and resulting energy loss tend to decrease along the vortex *** HLV changes the dominant frequency of the pressure fluctuations in the nearby flow field,the value of which increases from 1fr(the blade passing frequency)to 2fr with increased amplitude,mainly due to the lower pressure regions on the impeller suction surface(SS)and HLV vortex *** to the effect of rotor-stator interaction(RSI),the HLVs generated between two adjacent impeller blades are cut into several sections by the diffuser vanes and propagate and dissipate along the mainstream direction.

关键词： Bulb tubular pump corner separation entropy production pressure fluctuation visualization analysis

Membrane bioreactors for hospital wastewater treatment: recent advancements in membranes and processes

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Frontiers of Chemical Science and Engineering 2022年第5期16卷 634-660页

作者： Yan Zhao Yangbo Qiu Natalie Mamrol Longfei Ren Xin Li Jiahui Shao Xing Yang bart van der Bruggen Department of Chemical Engineering KU LeuvenB-3001 LeuvenBelgium School of Environmental Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Department of Materials Science and Engineering Massachusetts Institute of TechnologyCambridgeMA 02139USA

Discharged hospital wastewater contains various pathogenic microorganisms,antibiotic groups,toxic organic compounds,radioactive elements,and ionic *** contaminants harm the environment and human health causing the spread of ***,effective treatment of hospital wastewater is an urgent task for sustainable ***,with controllable porous and nonporous structures,have been rapidly developed for molecular *** particular,membrane bioreactor(MBR)technology demonstrated high removal efficiency toward organic compounds and low waste sludge *** further enhance the separation efficiency and achieve material recovery from hospital waste streams,novel concepts of MBRs and their applications are rapidly evolved through hybridizing novel membranes(non hydrophilic ultrafiltration/microfiltration)into the MBR units(hybrid MBRs)or the MBR as a pretreatment step and integrating other membrane processes as subsequent secondary purification step(integrated MBR-membrane systems).However,there is a lack of reviews on the latest advancement in MBR technologies for hospital wastewater treatment,and analysis on its major challenges and future *** review started with an overview of main pollutants in common hospital wastewater,followed by an understanding on the key performance indicators/criteria in MBR membranes(i.e.,solute selectivity)and processes(e.g.,fouling).Then,an in-depth analysis was provided into the recent development of hybrid MBR and integrated MBR-membrane system concepts,and applications correlated with wastewater sources,with a particular focus on hospital *** is anticipated that this review will shed light on the knowledge gaps in the field,highlighting the potential contribution of hybrid MBRs and integrated MBRmembrane systems toward global epidemic prevention.

关键词： membrane technology membrane bioreactor hospital wastewater hybrid MBR integrated MBR-membrane system

What if esca disease of grapevine were not a fungal disease?

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Fungal Diversity 2012年第3期54卷 51-67页

作者： Valérie Hofstetter bart Buyck Daniel Croll Olivier Viret Arnaud Couloux Katia Gindro Agroscope Changins-Wädenswil(ACW) Plant Protection Field Crops and Grapevine/Viticulture and EnologyCP10121260 Nyon1Switzerland Muséum National d’Histoire Naturelle Dépt.Systématique etévolutionCP 39UMR 720557 rue Cuvier75231 Paris cedex 05France Plant Pathology Institute for Integrative BiologyETH Zurich8092 ZurichSwitzerland Centre national de séquençage Genoscope2 rue Gaston-CrémieuxCP 570691057 Evry cedexFrance

Esca disease,which attacks the wood of grapevine,has become increasingly devastating during the past three decades and represents today a major concern in all wine-producing *** disease is attributed to a group of systematically diverse fungi that are considered to be latent pathogens,however,this has not been conclusively *** study presents the first in-depth comparison between the mycota of healthy and diseased plants taken from the same vineyard to determine which fungi become invasive when foliar symptoms of esca *** unprecedented high fungal diversity,158 species,is here reported exclusively from grapevine wood in a single Swiss vineyard *** identical mycota inhabits wood of healthy and diseased adult plants and presumed esca pathogens were widespread and occurred in similar frequencies in both plant *** esca-associated fungi are not transmitted from adult to nursery plants through the grafting *** the presumed esca-associated fungal pathogens are most likely saprobes decaying already senescent or dead wood resulting from intensive pruning,frost or other mecanical injuries as *** cause of esca disease therefore remains elusive and requires well executive scientific *** results question the assumed pathogenicity of fungi in other diseases of plants or animals where identical mycota are retrieved from both diseased and healthy individuals.

关键词： Fungal community Vitis vinifera Esca disease ITS based fungal identification Fungal pathogens

Spatiotemporally controlled,aptamers-mediated growth factor release locally manipulates microvasculature formation within engineered tissues

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Bioactive Materials 2022年第6期7卷 71-84页

作者： Deepti Rana Ajoy Kandar Nasim Salehi-Nik Ilyas Inci bart Koopman Jeroen Rouwkema Department of Biomechanical Engineering Technical Medical CentreFaculty of Engineering TechnologyUniversity of Twente7500AEEnschedethe Netherlands Izmir Democracy University Vocational School of Health ServicesDepartment of Dentistry ServicesDental Prosthetics TechnologyIzmir35140Turkey

Spatiotemporally controlled growth factor(GF)delivery is crucial for achieving functional vasculature within engineered ***,conventional GF delivery systems show inability to recapitulate the dynamic and heterogeneous nature of developing tissue’s biochemical ***,an aptamer-based programmable GF delivery platform is described that harnesses dynamic affinity interactions for facilitating spatiotemporal control over vascular endothelial GF(VEGF165)bioavailability within gelatin methacryloyl *** platform showcases localized VEGF165 sequestration from the culture medium(offering spatial-control)and leverages aptamer-complementary sequence(CS)hybridization for triggering VEGF165 release(offering temporal-control),without non-specific ***,extensive 3D co-culture studies(human umbilical vein-derived endothelial cells&mesenchymal stromal cells),in bi-phasic hydrogel systems revealed its fundamentally novel capability to selectively guide cell responses and manipulate lumen-like microvascular networks via spatiotemporally controlling VEGF165 bioavailability within 3D *** platform utilizes CS as an external biochemical trigger for guiding vascular morphogenesis which is suitable for creating dynamically controlled engineered tissues.

关键词： Aptamers Vascular endothelial growth factor Spatiotemporal release Co-culture Vascularization Biomaterials Tissue engineering

Calibration and Validation of Strategic Freight Transportation Planning Models with Limited Information

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Journal of Transportation Technologies 2016年第5期6卷 239-256页

作者： bart Jourquin Université catholique de Louvain ILSM Center for Supply Chain Management Mons Belgium

Strategic transportation network models are often used as support tools in the framework of decisions to be taken at the policy level, such as the Trans-European Network projects. These models are mostly setup using aggregated or limited data. If their calibration is regularly mentioned in the literature, their validation is barely discussed. In this paper, several modal choice model specifications that make only use of explanatory variables available at the network level are described and applied to a large scale case. A validation exercise is performed at three levels of aggregation. The paper is designed from a strategic transport planning perspective, and does not present new modal choice formulations or assignment procedures. Its main added value is the focus on calibration and validation considerations. Despite the limited explanatory information used, the global performance of the best models can be considered as satisfactory. However, the quality of the models varies from mode to mode, the use of railway transport being the most difficult to predict without more specific input.

关键词： Calibration Validation Network Freight Transport Modal Choice Assignment

Accessibility Measures in Modal Choice Models: A Proof of Concept Applied to Freight Transport

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Journal of Transportation Technologies 2023年第1期13卷 38-60页

作者： bart Jourquin Université Catholique de Louvain (UCLouvain) CORE Louvain-la-Neuve Belgium

Modal choice models applied to interregional or international freight transportation network models are often based on rather coarse origin-destination matrices, containing annual transported tonnages between (sub)regions, for instance. Generally, only basic (sometimes constructed) independent variables (transportation costs or transit times) are used because other variables such as shipment sizes, service frequencies, etc. are not available. Using origin-destination matrices and an assignment model, it is also possible to compute spatial accessibility measures that can further be used as additional explanatory variables. Indeed, several published studies have identified network accessibility as an important element in the mode-choice decision. This paper also shows that the inclusion of an accessibility measure in the utility functions of a logit model substantially improves the performance of a transportation network model, both in the modal choice and the assignment levels of the classical four-step model. Consequently, the assignment of the estimated modal demands results in more accurate estimated traffic on the networks. The model presented in this paper is to be considered as a proof of concept because its workflow should further be streamlined to make it easily useable by modelers.

关键词： Freight Transport Model Modal Choice Accessibility Assignment

Determination of the sensible heat effectiveness and pressure loss of a rotary regenerative heat exchanger using CFD

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Building Simulation 2023年第6期16卷 869-887页

作者： Vladimír Zmrhal Petr Zelenský Jindřich Boháč Martin barták Miroslav Kučera Roman Vavřička Faculty of Mechanical Engineering Department of Environmental EngineeringCzech Technical University in PragueTechnická416000Prague 6Czech Republic

The paper presents a new method to determine the sensible effectiveness and pressure loss of rotary regenerative heat exchangers using computational fluid dynamics(CFD).It is based on CFD simulations of a single thermal wheel microchannel with a small cross-sectional area and thin walls,with cyclic inlet and outlet boundary *** unique measurement set-ups were designed and built for the experimental measurement of the heat exchanger *** different types of thermal wheels were manufactured,measured,and simulated in ANSYS *** wheels achieve an effectiveness greater than 73%under certain(air flow)conditions,which is the minimum effectiveness required by Ecodesign(in the EU).For the examined exchangers,the effectiveness ranges from 66.5%to 83.3%,depending on the boundary conditions and geometric parameters of the *** highest sensible effectiveness is achieved by heat exchangers with the largest heat exchange surface Ac;on the other hand,these wheels have the largest pressure *** paper discusses the use of a simplifiedε-NTU correlation model for the HVAC systems(typically C*=1).The correlation model and CFD results were compared and found to be different from each *** results of the CFD simulation were compared with measurements to prove that the proposed simulation method can predict the behaviour of the real heat exchanger as a *** was demonstrated that the sensible effectiveness and pressure loss of the rotary heat exchanger predicted by the CFD simulations correspond well to the measured values within the measurement uncertainty±1.3%.The proposed method can be used for the comparison of different rotary regenerative heat exchangers before their manufacturing and for verification that they meet the EU Ecodesign requirements set by the current *** reduces the cost of the initial optimisation and testing of new designs.

关键词： rotary heat exchanger heat wheel microchannel heat recovery sensible effectiveness pressureloss computer fluid dynamics experiment

Improvement of the SST γ-Re_(θt) transition model for flows along a curved hydrofoil

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Journal of Hydrodynamics 2021年第3期33卷 520-533页

作者： Chang-liang Ye Chao-yue Wang Dan Zi Yuan Tang bart.P.M.van Esch Fu-jun Wan College of Water Resources and Civil Engineering China Agricultural UniversityBeijing100083China Department of Mechanical Engineering Eindhoven University of TechnologyEindhovenThe Netherlands Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System Beijing100083China

The transition in the boundary-layer flow affects the hydrodynamic performances of hydraulic machineries,as the key components in the ship propulsion *** shear stress transfer(SST)γ-Re_(θt) transition model is an important prediction tool in the boundary layer simulation for *** present paper improves the prediction accuracy of the SST γ-Re_(θt) model for the boundary layers along a curved *** SST γ-Re_(θt) transition model for the flows along a curved hydrofoil is improved by introducing a correction to the transition onset Reynolds number Reθ***,the transition onset locations for the flows along the hydrofoils of different curvatures are obtained by the large eddy simulation and by using the SST γ-Re_(θt) ***,the transition onset Reynolds numbers Reθt in the SST γ-Re_(θt) model is modified to ensure that the predicted boundary layer parameters are consistent with the large eddy simulation(LES)*** correlation function between the curvature ratio and the modified transition onset Reynolds number is obtained and subsequently used as a correction function in the original SST γ-Re_(θt) *** test cases are used to evaluate the performance of the improved SST γ-Re_(θt) *** the NACA0035 hydrofoil with a large curvature,the predicted results obtained by using the improved SST γ-Re_(θt) model are quite consistent with the experimental data,which indicates the advantages of the improved model in predicting the boundary layer transition along a *** the test cases of the NACA0016 hydrofoil with a mild curvature and the NACA66(mod)-312 hydrofoil,the prediction results of the improved model are in good agreement with the experimental results in terms of the wake region and the boundary layer parameters,which indicates that the improved SST γ-Re_(θt) model can serve as a powerful tool in the design and the optimization of hydraulic machineries such as the waterjet pumps or the naval propellers.

关键词： Hydrodynamics transition model curvature effect hydrofoil boundary layer transition

The free-electron laser FLASH

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High Power Laser Science and Engineering 2015年第3期3卷 28-40页

作者： Siegfried Schreiber bart Faatz Deutsches Elektronen-Synchrotron

FLASH at DESY, Hamburg, Germany is the first free-electron laser(FEL) operating in the extreme ultraviolet(EUV)and soft x-ray wavelength range. FLASH is a user facility providing femtosecond short pulses with an unprecedented peak and average brilliance, opening new scientific opportunities in many disciplines. The first call for user experiments has been launched in 2005. The FLASH linear accelerator is based on TESLA superconducting technology, providing several thousands of photon pulses per second to user experiments. Probing femtosecond-scale dynamics in atomic and molecular reactions using, for instance, a combination of x-ray and optical pulses in a pump and probe arrangement,as well as single-shot diffraction imaging of biological objects and molecules, are typical experiments performed at the facility. We give an overview of the FLASH facility, and describe the basic principles of the accelerator. Recently,FLASH has been extended by a second undulator beamline(FLASH2) operated in parallel to the first beamline, extending the capacity of the facility by a factor of two.

关键词： bunch compression free-electron laser high-gain FEL process photo injector SASE superconducting accelerator undulator