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Experimental and numerical investigation to elucidate the fluid flow through packed beds with structured particle packings

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Particuology 2024年第6期89卷 218-237页

作者： Shirin Patil Christian Gorges Joel Lòpez Bonilla Moritz Stelter Frank Beyrau Berend van Wachem Laboratory of Technical Thermodynamics Otto-von-Guericke-Universität MagdeburgUniversitätsplatz 239106 MagdeburgGermany Chair of Mechanical Process Engineering Otto-von-Guericke-Universität MagdeburgUniversitätsplatz 239106 MagdeburgGermany

The present paper presents an experimental and numerical investigation of the dispersion of the gaseous jet flow and co-flow for the simple unit cell(SUC)and body-centred cubic(BCC)configuration of particles in packed beds.The experimental setup is built in such a way that suitable and simplified boundary conditions are imposed for the corresponding numerical framework,so the simulations can be done under very similar conditions as the experiments.Accordingly,a porous plate is used for the co-flow to achieve the uniform velocity and the fully developed flow is ensured for the jet flow.The SUC and BCC particle beds consist of 3D-printed spheres,and the non-isotropy near the walls is mostly eliminated by placing half-spheres at the channel walls.The flow velocities are analysed directly at the exit of the particle bed for both beds over 36 pores for the SUC configuration and 60 pores for the BCC configuration,for particle Reynolds numbers of 200,300,and 400.Stereo particle image velocimetry is experimentally arranged in such a way that the velocities over the entire region at the exit of the packed bed are obtained instantaneously.The numerical method consists of a state-of-the-art immersed boundary method with adaptive mesh refinement.The paper presents the pore jet structure and velocity field exiting from each pore for the SUC and BCC packed particle beds.The numerical and experimental studies show a good agreement for the SUC configuration for all flow velocities.For the BCC configuration,some differences can be observed in the pore jet flow structure between the simulations and the experiments,but the general flow velocity distribution shows a good overall agreement.The axial velocity is generally higher for the pores located near the centre of the packed bed than for the pores near the wall.In addition,the axial velocities are observed to increase near the peripheral pores of the packed bed.This behaviour is predominant for the BCC configuration as compared to the SUC configuration.The velocities near the per

关键词： Uniform particle packing packed bed reactor Stereo particle image velocimetry Immersed boundary method

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Time-resolved characteristics of a nanosecond pulsed multi-hollow needle plate packed bed dielectric barrier discharge

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Plasma Science and Technology 2024年第7期26卷 48-57页

作者：秦亮李瑶郭浩姜楠宋颖贾锐周雄峰袁皓杨德正 Key Laboratory of Materials Modification by Laser Ionand Electron Beams(Dalian University of Technology)Ministry of EducationDalian 116024People’s Republic of China School of Electrical Engineering Dalian University of TechnologyDalian 116024People’s Republic of China State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System Luoyang 471003People’s Republic of China School of Physics and Materials Engineering Dalian Minzu UniversityDalian 116600People’s Republic of China

In this paper,self-designed multi-hollow needle electrodes are used as a high-voltage electrode in a packed bed dielectric barrier discharge reactor to facilitate fast gas flow through the active discharge area and achieve large-volume stable discharge.The dynamic characteristics of the plasma,the generated active species,and the energy transfer mechanisms in both positive discharge(PD)and negative discharge(ND)are investigated by using fast-exposure intensified charge coupled device(ICCD)images and time-resolved optical emission spectra.The experimental results show that the discharge intensity,number of discharge channels,and discharge volume are obviously enhanced when the multi-needle electrode is replaced by a multihollow needle electrode.During a single voltage pulse period,PD mainly develops in a streamer mode,which results in a stronger discharge current,luminous intensity,and E/N compared with the diffuse mode observed in ND.In PD,as the gap between dielectric beads changes from 0 to250μm,the discharge between the dielectric bead gap changes from a partial discharge to a standing filamentary micro-discharge,which allows the plasma to leave the local area and is conducive to the propagation of surface streamers.In ND,the discharge only appears as a diffusionlike mode between the gap of dielectric beads,regardless of whether there is a discharge gap.Moreover,the generation of excited states N_(2)^(+)(B^(2)∑_(u)^(+))and N2(C^(3)Π_(u))is mainly observed in PD,which is attributed to the higher E/N in PD than that in ND.However,the generation of the OH(A^(2)∑^(+))radical in ND is higher than in PD.It is not directly dominated by E/N,but mainly by the resonant energy transfer process between metastable N_(2)(A^(3)∑_(u)^(+))and OH(X^(2)Π).Furthermore,both PD and ND demonstrate obvious energy relaxation processes of electron-to-vibration and vibration-to-vibration,and no vibration-to-rotation energy relaxation process is observed.

关键词： packed bed reactor multi-hollow needle electrodes positive and negative discharges optical emission spectra time-resolved images

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Comparing two IBM implementations for the simulation of uniform packed beds

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Particuology 2024年第3期86卷 1-12页

作者： Christian Gorges Maximilian Brommer Christin Velten Siegmar Wirtz Enric Illana Mahiques Viktor Scherer Katharina Zahringer Berend van Wachem Mechanical Process Engineering Otto-von-Guericke-Universitat MagdeburgUniversitatsplatz 239106MagdeburgGermany Department of Energy Plant Technology Ruhr-Universitat BochumUniversitatsstraBe 15044780BochumGermany Laboratory of Fluid Dynamics and Technical Flows Otto-von-Guericke-Universitat MagdeburgUniversitatsplatz 239106MagdeburgGermany

Nowadays,the design of fixed packed bed reactors still relies on empirical correlations,which,especially for small tube to particle diameter ratios,are mostly too inaccurate because of the presence of wall effects.Therefore,the simulation of fixed packed bed reactors plays an important role to predict and control the flow and process parameters in such,nowadays and in the future.Because of its straightforward applicability to non-uniform packings with particles of arbitrary shapes,the immersed boundary method(IBM)has advantages over other numerical methods and is used more and more frequently.This paper compares two approaches of IBMs for the simulation of fixed bed reactors with spherical shaped particles.The classic,smooth approach is compared to the straightforward to implement blocked-off method for velocity fields above the fixed bed for particle Reynolds numbers of 300 and 500.Results from experimental inline PIV-measurements of the reactor to be simulated serve as a basis for comparison.Very good agreement with the experiment is found for both simulation methodologies with higher resolutions,considering the more stable flow at a particle Reynolds number of 300.Differences in the different IBM approaches occurred for the more unsteady flow at a particle Reynolds number of 500.Compared to the blocked-off method,the smooth IBM reflects the formation of additional jets and recirculation zones better right above the bed,though increasing the fluid mesh resolution improves the accuracy of the blocked-off method.Overall,a more diffusive behaviour is found for the blocked-off simulations due to the stairstep representation,which is avoided by using interpolation stencils as in the smooth IBM.With higher mesh refinement in the blocked-off IBM this effect can be reduced,but this also increases the computational effort.

关键词： Immersed boundary method packed bed reactor Uniform particle packing

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Meta-analysis of CO_(2) conversion,energy efficiency,and other performance data of plasma-catalysis reactors with the open access PIONEER database

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Journal of Energy Chemistry 2023年第11期86卷 318-342,I0007页

作者： Antoine Salden Maik Budde Carolina A.Garcia-Soto Omar Biondo Jairo Barauna Marzia Faedda Beatrice Musig ChloéFromentin Minh Nguyen-Quang Harry Philpott Golshid Hasrack Domenico Aceto Yuxiang Cai Federico Azzolina Jury Annemie Bogaerts Patrick Da Costa Richard Engeln María Elena Gálvez Timo Gans Tomas Garcia Vasco Guerra Carlos Henriques Monika Motak Maria Victoria Navarro Vasile I.Parvulescu Gerard Van Rooij Bogdan Samojeden Ana Sobota Paolo Tosi Xin Tu Olivier Guaitella Department of Physics University of Trento38100 PovoItaly Department of Applied Physics and Science Education Eindhoven University of Technology5600 MB EindhovenThe Netherlands Instituto de Plasmas e Fusão Nuclear Instituto Superior TécnicoUniversidade de Lisboa1049-001 LisboaPortugal LPP CNRSÉcole PolytechniqueSorbonne UniversitéUniversitéParis-SaclayIP-Paris 91128 PalaiseauFrance Department of Organic Chemistry Biochemistry and CatalysisUniversity of BucharestBucharestRomania Research Group PLASMANT Department of ChemistryUniversity of AntwerpUniversiteitsplein 1Wilrijk B-2610Belgium DIFFER 5612AJ EindhovenThe Netherlands Instituto de Carboquímica ICB-CSIC Zaragoza 50018Spain Faculty of Energy and Fuels AGH University of KrakowKrakowPoland Institut Jean le Rond d’Alembert CNRS UMR 7190-Sorbonne UniversitéSaint-Cyr l’Ecole 78210France Laboratoire Catalyse et Spectrochimie(LCS) CNRS-ENSICAEN-Universitéde Caen6 boulevard du Maréchal-Juin14000 CaenFrance CQE Centro de Química EstruturalInstituto Superior TécnicoUniversidade de LisboaAv.Rovisco Pais1049-001 LisboaPortugal School of Physical Sciences and National Centre for Plasma Science and Technology Faculty of Science and HealthDublin City UniversityDublinIreland ASML De Run 65015504 DR VeldhovenThe Netherlands Faculty of Science and Engineering Maastricht University6229 GS MaastrichtThe Netherlands CNR Istituto per la Scienza e Tecnologia dei Plasmi(ISTP)Italy Department of Electrical Engineering and Electronics University of LiverpoolLiverpool L693GJUK

This paper brings the comparison of performances of CO_(2)conversion by plasma and plasma-assisted catalysis based on the data collected from literature in this field,organised in an open access online database.This tool is open to all users to carry out their own analyses,but also to contributors who wish to add their data to the database in order to improve the relevance of the comparisons made,and ultimately to improve the efficiency of CO_(2)conversion by plasma-catalysis.The creation of this database and database user interface is motivated by the fact that plasma-catalysis is a fast-growing field for all CO_(2)conversion processes,be it methanation,dry reforming of methane,methanolisation,or others.As a result of this rapid increase,there is a need for a set of standard procedures to rigorously compare performances of different systems.However,this is currently not possible because the fundamental mechanisms of plasma-catalysis are still too poorly understood to define these standard procedures.Fortunately however,the accumulated data within the CO_(2)plasma-catalysis community has become large enough to warrant so-called“big data”studies more familiar in the fields of medicine and the social sciences.To enable comparisons between multiple data sets and make future research more effective,this work proposes the first database on CO_(2)conversion performances by plasma-catalysis open to the whole community.This database has been initiated in the framework of a H_(2)0_(2)0 European project and is called the“PIONEER Data Base”.The database gathers a large amount of CO_(2)conversion performance data such as conversion rate,energy efficiency,and selectivity for numerous plasma sources coupled with or without a catalyst.Each data set is associated with metadata describing the gas mixture,the plasma source,the nature of the catalyst,and the form of coupling with the plasma.Beyond the database itself,a data extraction tool with direct visualisation features or advanced filtering functionalities has been developed a

关键词： Open-access database on plasma-catalysis experiment CO_(2) conversion Plasma-catalysis Carbon capture and utilisation(CCU) Energy efficiency Specific energy input Dielectric barrier discharge packed bed reactor Methanation Dry reforming of methane

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Studies on packed bed Electrochemical reactors

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Progress in Natural Science:Materials International 1993年第2期3卷 181-186页

作者：许文林刘河洲袁渭康 PRC Shanghai 200237 The National United Chemical Engineering Laboratory East China University of Chemical Technology

1 Introduction packed bed electrochemical reactors are three-dimensional electrode reactors.They have many important advantages over conventional electrochemical reactors such as plate

关键词： electrochemical reactor packed bed electrode packed bed reactor

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