Particuology最新文献_第3页

Effect of continuous single bubble injection on binary mixtures in a fluidized bed

IF 4.1 2区材料科学 Q2 ENGINEERING, CHEMICAL

Particuology

Pub Date : 2025-03-15 DOI: 10.1016/j.partic.2025.02.025

Ali Rabbani, Saman Kazemi, Rahmat Sotudeh-Gharebagh, Navid Mostoufi, Reza Zarghami

In this study, single bubbles are injected into a binary mixture comprising both spherical and rod-like particles to explore bubble shape and diameter. Effect of continuously injecting bubbles into a fluidized bed at a velocity near the minimum fluidization velocity on mixing is investigated. The combination of computational fluid dynamics and discrete element methods (CFD-DEM) as well as an experimental setup were used to investigate the mixing of particles in this situation. The rod-like particles were modeled by multi-sphere method. To assess the mixing performance, both qualitative and quantitative measures were employed, including visual examination of fluidized beds and evaluating subdomain-based mixing index. It was shown that the continuous injection of single bubbles can significantly improve mixing compared with the case of no bubble injection. Furthermore, when the number of rod-like particles increases, the continuous injection of single bubbles is an effective technique for improving mixing. In processes where gas utilization is critical and cost optimization is paramount, continuous injection of bubbles can reduce the gas volume required. This method is particularly beneficial in industries where high gas volumes are impractical or require significant equipment changes. It also helps break down dead zones and channeling phenomena in fluidized beds, especially when rod-like particles are present.

{"title":"Effect of continuous single bubble injection on binary mixtures in a fluidized bed","authors":"Ali Rabbani, Saman Kazemi, Rahmat Sotudeh-Gharebagh, Navid Mostoufi, Reza Zarghami","doi":"10.1016/j.partic.2025.02.025","DOIUrl":"10.1016/j.partic.2025.02.025","url":null,"abstract":"<div><div>In this study, single bubbles are injected into a binary mixture comprising both spherical and rod-like particles to explore bubble shape and diameter. Effect of continuously injecting bubbles into a fluidized bed at a velocity near the minimum fluidization velocity on mixing is investigated. The combination of computational fluid dynamics and discrete element methods (CFD-DEM) as well as an experimental setup were used to investigate the mixing of particles in this situation. The rod-like particles were modeled by multi-sphere method. To assess the mixing performance, both qualitative and quantitative measures were employed, including visual examination of fluidized beds and evaluating subdomain-based mixing index. It was shown that the continuous injection of single bubbles can significantly improve mixing compared with the case of no bubble injection. Furthermore, when the number of rod-like particles increases, the continuous injection of single bubbles is an effective technique for improving mixing. In processes where gas utilization is critical and cost optimization is paramount, continuous injection of bubbles can reduce the gas volume required. This method is particularly beneficial in industries where high gas volumes are impractical or require significant equipment changes. It also helps break down dead zones and channeling phenomena in fluidized beds, especially when rod-like particles are present.</div></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":"100 ","pages":"Pages 62-77"},"PeriodicalIF":4.1,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental and numerical simulation study of particles flow in the microchannel equipped with fan-shaped rib on sidewall

IF 4.1 2区材料科学 Q2 ENGINEERING, CHEMICAL

Particuology

Pub Date : 2025-03-15 DOI: 10.1016/j.partic.2025.02.026

Zhenyu Yang , Xiaolong Li , Weifeng Zhang , Tianyi Cai , Wu Zhou

Microchannels are widely used in electronic device cooling due to their efficient heat dissipation performance, but particle deposition is still a major challenge limiting their performance. To design and optimize efficient microfluidic devices, this paper proposes to introduce fan-shaped ribs within the microchannels to reduce particle deposition. The placement of fan ribs of different heights in the microchannel was first experimentally determined, and then the particle motion characteristics were further investigated by numerical simulations. The results show that the fan-shaped ribs can effectively reduce particle deposition and exhibit greater deposition inhibition with increasing rib height. The channel constriction induced by the rib structure promotes the radial diffusion of particles in the downstream, and at the same time significantly enhances the radial component of the particle flow, which is improved by 5.76 %, 7.98 %, and 10.86 %, respectively. In addition, recursive analysis revealed that the incorporation of fan-shaped ribs shifted the particle flow from a homogeneous, periodic mode to a more abrupt diffusion mode, which contributed to the improvement of particle dispersion. This study provides a new strategy without the use of surfactants, which provides a reference for the optimized design of microchannel cooling systems.

{"title":"Experimental and numerical simulation study of particles flow in the microchannel equipped with fan-shaped rib on sidewall","authors":"Zhenyu Yang , Xiaolong Li , Weifeng Zhang , Tianyi Cai , Wu Zhou","doi":"10.1016/j.partic.2025.02.026","DOIUrl":"10.1016/j.partic.2025.02.026","url":null,"abstract":"<div><div>Microchannels are widely used in electronic device cooling due to their efficient heat dissipation performance, but particle deposition is still a major challenge limiting their performance. To design and optimize efficient microfluidic devices, this paper proposes to introduce fan-shaped ribs within the microchannels to reduce particle deposition. The placement of fan ribs of different heights in the microchannel was first experimentally determined, and then the particle motion characteristics were further investigated by numerical simulations. The results show that the fan-shaped ribs can effectively reduce particle deposition and exhibit greater deposition inhibition with increasing rib height. The channel constriction induced by the rib structure promotes the radial diffusion of particles in the downstream, and at the same time significantly enhances the radial component of the particle flow, which is improved by 5.76 %, 7.98 %, and 10.86 %, respectively. In addition, recursive analysis revealed that the incorporation of fan-shaped ribs shifted the particle flow from a homogeneous, periodic mode to a more abrupt diffusion mode, which contributed to the improvement of particle dispersion. This study provides a new strategy without the use of surfactants, which provides a reference for the optimized design of microchannel cooling systems.</div></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":"100 ","pages":"Pages 45-61"},"PeriodicalIF":4.1,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Minimum fluidization velocity prediction of Geldart A dense medium in gas-solid separation fluidized bed

IF 4.1 2区材料科学 Q2 ENGINEERING, CHEMICAL

Particuology

Pub Date : 2025-03-14 DOI: 10.1016/j.partic.2025.03.002

Dan Wang , Yangfan Xu , Feng Lu , Ziyuan Li , Daohui Lv , Chenlong Duan , Chenyang Zhou

The minimum fluidization velocity is a pivotal parameter in the study of fluidization behavior within air dense medium fluidized beds, significantly affecting the design and operational efficiency of these systems. This research explores the fluidization characteristics of Geldart A magnetite particles and Geldart B magnetite powder particles through experimental investigations. The results show that the minimum fluidization velocity of Geldart A and Geldart B particles differs due to both particle size and density. Operating conditions, such as gas distribution uniformity and flow rate fluctuations, also have a significant impact. These findings offer valuable guidance for improving the design and operation of fluidized bed reactors. To accurately estimate the minimum fluidization velocity of Geldart A magnetite powder particles, this study extends classical equations and introduces new correlation coefficients. A summarized and analytical comparison of literature data and experimental results data demonstrate that the proposed correlation coefficients are both accurate and reliable within the defined range, with a prediction error of less than 0.2 cm/s when validated against literature and experimental data. This study furnishes experimental evidence and theoretical insights into the fluidization behavior of diverse particle types, thereby facilitating the optimization of fluidized bed design.

{"title":"Minimum fluidization velocity prediction of Geldart A dense medium in gas-solid separation fluidized bed","authors":"Dan Wang , Yangfan Xu , Feng Lu , Ziyuan Li , Daohui Lv , Chenlong Duan , Chenyang Zhou","doi":"10.1016/j.partic.2025.03.002","DOIUrl":"10.1016/j.partic.2025.03.002","url":null,"abstract":"<div><div>The minimum fluidization velocity is a pivotal parameter in the study of fluidization behavior within air dense medium fluidized beds, significantly affecting the design and operational efficiency of these systems. This research explores the fluidization characteristics of Geldart A magnetite particles and Geldart B magnetite powder particles through experimental investigations. The results show that the minimum fluidization velocity of Geldart A and Geldart B particles differs due to both particle size and density. Operating conditions, such as gas distribution uniformity and flow rate fluctuations, also have a significant impact. These findings offer valuable guidance for improving the design and operation of fluidized bed reactors. To accurately estimate the minimum fluidization velocity of Geldart A magnetite powder particles, this study extends classical equations and introduces new correlation coefficients. A summarized and analytical comparison of literature data and experimental results data demonstrate that the proposed correlation coefficients are both accurate and reliable within the defined range, with a prediction error of less than 0.2 cm/s when validated against literature and experimental data. This study furnishes experimental evidence and theoretical insights into the fluidization behavior of diverse particle types, thereby facilitating the optimization of fluidized bed design.</div></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":"100 ","pages":"Pages 27-35"},"PeriodicalIF":4.1,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Modelling of heat transfer in moving granular assemblies with a focus on radiation using the discrete ordinate method: A DEM-CFD approach

IF 4.1 2区材料科学 Q2 ENGINEERING, CHEMICAL

Particuology

Pub Date : 2025-03-14 DOI: 10.1016/j.partic.2025.02.024

Rezvan Abdi, Bo Jaeger, Enric Illana, Siegmar Wirtz, Martin Schiemann, Viktor Scherer

Discrete Ordinates Method (DOM) is a model for thermal radiation exchange in opaque media. In this study, the DOM formulation is employed within the framework of the Discrete Element Method coupled with Computational Fluid Dynamics (DEM-CFD), thus including full radiative heat exchange among the phases involved. This is done by adjusting the absorption coefficient, emission coefficient, and net radiative heat flux of particles by incorporating local porosity into equations. A key objective is to represent radiation propagation for different packing densities in packed beds accurately.

The model is validated by comparing the results with available data from the literature for simulations with a P1 radiation model and corresponding experiments. The validation configuration is a heated box filled with spherical particles under vacuum conditions.

As an application example, the radiative heat exchange between an enclosure at high temperature and moving layers of spherical particles concurrently passed by a gas in crossflow is studied. Three packing densities (dilute, moderate, and dense) are examined to evaluate radiation penetration into the particle ensemble. Convective and contact heat transfer are also considered. The DEM-CFD coupling is a non-resolved approach, where the influence of particles on the flow field is accounted for by momentum and energy source terms together with a porosity field (Averaged Volume Method (AVM)).

Effect of convective, conductive and radiative heat transfer is analysed based on the evolution of incident radiation flux, spatial distributions of particle surface and fluid temperatures, and particle temperature histograms. It becomes obvious that radiation dominates the system, and that packing density defines the penetration depth of radiation. Conduction mainly leads to a smoothening of particle temperature distribution in the system.

{"title":"Modelling of heat transfer in moving granular assemblies with a focus on radiation using the discrete ordinate method: A DEM-CFD approach","authors":"Rezvan Abdi, Bo Jaeger, Enric Illana, Siegmar Wirtz, Martin Schiemann, Viktor Scherer","doi":"10.1016/j.partic.2025.02.024","DOIUrl":"10.1016/j.partic.2025.02.024","url":null,"abstract":"<div><div>Discrete Ordinates Method (DOM) is a model for thermal radiation exchange in opaque media. In this study, the DOM formulation is employed within the framework of the Discrete Element Method coupled with Computational Fluid Dynamics (DEM-CFD), thus including full radiative heat exchange among the phases involved. This is done by adjusting the absorption coefficient, emission coefficient, and net radiative heat flux of particles by incorporating local porosity into equations. A key objective is to represent radiation propagation for different packing densities in packed beds accurately.</div><div>The model is validated by comparing the results with available data from the literature for simulations with a P1 radiation model and corresponding experiments. The validation configuration is a heated box filled with spherical particles under vacuum conditions.</div><div>As an application example, the radiative heat exchange between an enclosure at high temperature and moving layers of spherical particles concurrently passed by a gas in crossflow is studied. Three packing densities (dilute, moderate, and dense) are examined to evaluate radiation penetration into the particle ensemble. Convective and contact heat transfer are also considered. The DEM-CFD coupling is a non-resolved approach, where the influence of particles on the flow field is accounted for by momentum and energy source terms together with a porosity field (Averaged Volume Method (AVM)).</div><div>Effect of convective, conductive and radiative heat transfer is analysed based on the evolution of incident radiation flux, spatial distributions of particle surface and fluid temperatures, and particle temperature histograms. It becomes obvious that radiation dominates the system, and that packing density defines the penetration depth of radiation. Conduction mainly leads to a smoothening of particle temperature distribution in the system.</div></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":"100 ","pages":"Pages 78-94"},"PeriodicalIF":4.1,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An in-depth numerical simulation analysis of the hydrodynamic characteristics of internally-reinforced spouted beds

IF 4.1 2区材料科学 Q2 ENGINEERING, CHEMICAL

Particuology

Pub Date : 2025-03-14 DOI: 10.1016/j.partic.2025.03.003

Qin Bai , Feng Wu , Junhao Hao , Xiaolong Li , Zhian Deng

Due to the lack of gas-solid radial mixing in conventional spouted bed (CSB), particles are prone to accumulation and the formation of flow dead zones. To address the limitations of CSBs, this study, for the first time, the combination optimization of the two strengthening internal components of multi-jets and draft tube was carried out, and two new types of internal strengthening structural spouted beds were proposed: the Integral Multi-jets Draft-tube Spout-fluidized Bed (IMDSFB), and the Integral Multi-jets Open-hole Draft-tube Spout-fluidized Bed (IMODSFB). At the same time, the hydrodynamic characteristics of IMDSFB and IMODSFB are studied by numerical simulation for the first time and compared with the draft tube spouted bed (DTSB) and CSB. Results indicate that compared to CSB, the spouting heights of the DTSB, IMDSFB, and IMODSFB were enhanced by 2.92°%, 14.75°%, and 7.94°%, respectively, and the dead zone of the DTSB, IMDSFB, and IMODSFB decreased by 14°%, 1°%, and 5°%, respectively. Compared to the CSB and DTSB, the addition of novel internal components notably improved the radial velocities of both gas and particles, as well as the gas-solid slip velocity, while reducing flow dead zones within the bed. Furthermore, the gas turbulence kinetic energy in the novel spout-fluidized beds was higher, with increased fluctuations of gas velocity in the spouting region. The granular temperature in the IMDSFB and IMODSFB was higher than in the CSB and DTSB, indicating enhanced particle fluctuations within the bed. These improvements contribute to more efficient gas-solid phase interactions, thereby enhancing the overall performance of the spouted bed.

{"title":"An in-depth numerical simulation analysis of the hydrodynamic characteristics of internally-reinforced spouted beds","authors":"Qin Bai , Feng Wu , Junhao Hao , Xiaolong Li , Zhian Deng","doi":"10.1016/j.partic.2025.03.003","DOIUrl":"10.1016/j.partic.2025.03.003","url":null,"abstract":"<div><div>Due to the lack of gas-solid radial mixing in conventional spouted bed (CSB), particles are prone to accumulation and the formation of flow dead zones. To address the limitations of CSBs, this study, for the first time, the combination optimization of the two strengthening internal components of multi-jets and draft tube was carried out, and two new types of internal strengthening structural spouted beds were proposed: the Integral Multi-jets Draft-tube Spout-fluidized Bed (IMDSFB), and the Integral Multi-jets Open-hole Draft-tube Spout-fluidized Bed (IMODSFB). At the same time, the hydrodynamic characteristics of IMDSFB and IMODSFB are studied by numerical simulation for the first time and compared with the draft tube spouted bed (DTSB) and CSB. Results indicate that compared to CSB, the spouting heights of the DTSB, IMDSFB, and IMODSFB were enhanced by 2.92°%, 14.75°%, and 7.94°%, respectively, and the dead zone of the DTSB, IMDSFB, and IMODSFB decreased by 14°%, 1°%, and 5°%, respectively. Compared to the CSB and DTSB, the addition of novel internal components notably improved the radial velocities of both gas and particles, as well as the gas-solid slip velocity, while reducing flow dead zones within the bed. Furthermore, the gas turbulence kinetic energy in the novel spout-fluidized beds was higher, with increased fluctuations of gas velocity in the spouting region. The granular temperature in the IMDSFB and IMODSFB was higher than in the CSB and DTSB, indicating enhanced particle fluctuations within the bed. These improvements contribute to more efficient gas-solid phase interactions, thereby enhancing the overall performance of the spouted bed.</div></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":"100 ","pages":"Pages 1-13"},"PeriodicalIF":4.1,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Investigating rotational characteristics and contact mechanisms of star-like shapes using multiellipse-based DEM

IF 4.1 2区材料科学 Q2 ENGINEERING, CHEMICAL

Particuology

Pub Date : 2025-03-13 DOI: 10.1016/j.partic.2025.03.001

Yang Li , Haoran Jiang

This study investigates the effect of non-convexity on the rotational characteristics and contact mechanisms of two-dimensional star-like shapes using multiellipse-based discrete element modeling (DEM). Biaxial shearing tests are conducted on star-shaped geometries with varying arm numbers and aspect ratios of the intersecting ellipses. The results indicate a non-monotonic relationship between overall particle rotation and increasing non-convexity, highlighting a more pronounced role of non-convexity in promoting local interlocking at particle contacts. Moreover, high non-convexity facilitates the formation of multiple contact points between interacting particles, which generally show higher stability than single-point contacts, except in the case of highly non-convex shapes. The geometric complexity introduced by non-convexity induces significant heterogeneity in the contact network and inter-particle force distributions. Finally, a spatial analysis of contact patterns reveals the coexistence of interlocking and excluded volume effects, where the alignment of the arms and valleys results in two distinct peaks in contact frequency and governs the initiation location of particle interactions. Meanwhile, the intermediate surfaces become less involved in particle contacts as non-convexity increases.

{"title":"Investigating rotational characteristics and contact mechanisms of star-like shapes using multiellipse-based DEM","authors":"Yang Li , Haoran Jiang","doi":"10.1016/j.partic.2025.03.001","DOIUrl":"10.1016/j.partic.2025.03.001","url":null,"abstract":"<div><div>This study investigates the effect of non-convexity on the rotational characteristics and contact mechanisms of two-dimensional star-like shapes using multiellipse-based discrete element modeling (DEM). Biaxial shearing tests are conducted on star-shaped geometries with varying arm numbers and aspect ratios of the intersecting ellipses. The results indicate a non-monotonic relationship between overall particle rotation and increasing non-convexity, highlighting a more pronounced role of non-convexity in promoting local interlocking at particle contacts. Moreover, high non-convexity facilitates the formation of multiple contact points between interacting particles, which generally show higher stability than single-point contacts, except in the case of highly non-convex shapes. The geometric complexity introduced by non-convexity induces significant heterogeneity in the contact network and inter-particle force distributions. Finally, a spatial analysis of contact patterns reveals the coexistence of interlocking and excluded volume effects, where the alignment of the arms and valleys results in two distinct peaks in contact frequency and governs the initiation location of particle interactions. Meanwhile, the intermediate surfaces become less involved in particle contacts as non-convexity increases.</div></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":"99 ","pages":"Pages 210-225"},"PeriodicalIF":4.1,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Constructing Pt/ZnO@SiO2 composite structures to enhance the thermal stability and CO oxidation activity of Pt-based catalysts

IF 4.1 2区材料科学 Q2 ENGINEERING, CHEMICAL

Particuology

Pub Date : 2025-03-13 DOI: 10.1016/j.partic.2025.02.023

Youwei Song , Liyun Zhang , Ying Zhang , Yongzhao Wang , Zhuang Xu , Bingsen Zhang

The catalytic oxidation of carbon monoxide (CO) to carbon dioxide (CO₂) is an effective way to eliminate the harmful effects of CO, with catalysts playing a crucial role in this process. Although Pt-based catalysts have been widely used for CO oxidation, the low-temperature activity and thermal stability still need to be improved. In this study, a Pt/ZnO@SiO₂ composite structure was constructed by coating Pt/ZnO catalysts with a thin SiO₂ layer. The influence of SiO₂ overcoating layer on the sintering behavior of Pt nanoparticles (NPs) and on the catalytic performance of the Pt catalyst for CO oxidation was investigated in detail. And the results were compared with those without SiO₂ overcoating layer. Investigations found that the SiO₂ coating layer effectively inhibited the sintering of Pt NPs at high temperatures, enhancing the thermal stability. In addition, the SiO₂ overcoating layer improved the catalytic activity of the Pt-based catalyst by inducing higher concentration of oxygen vacancies on the catalyst surface as well as weakening the CO adsorption, which could enhance the adsorption and activation ability of oxygen. Meanwhile, the presence of SiO₂ overcoating layer improved the catalytic stability during CO oxidation reaction. This work provides an important reference for the design and development of supported Pt-based catalysts with excellent thermal stability and catalytic activity for CO oxidation.

{"title":"Constructing Pt/ZnO@SiO2 composite structures to enhance the thermal stability and CO oxidation activity of Pt-based catalysts","authors":"Youwei Song , Liyun Zhang , Ying Zhang , Yongzhao Wang , Zhuang Xu , Bingsen Zhang","doi":"10.1016/j.partic.2025.02.023","DOIUrl":"10.1016/j.partic.2025.02.023","url":null,"abstract":"<div><div>The catalytic oxidation of carbon monoxide (CO) to carbon dioxide (CO<sub>2</sub>) is an effective way to eliminate the harmful effects of CO, with catalysts playing a crucial role in this process. Although Pt-based catalysts have been widely used for CO oxidation, the low-temperature activity and thermal stability still need to be improved. In this study, a Pt/ZnO@SiO<sub>2</sub> composite structure was constructed by coating Pt/ZnO catalysts with a thin SiO<sub>2</sub> layer. The influence of SiO<sub>2</sub> overcoating layer on the sintering behavior of Pt nanoparticles (NPs) and on the catalytic performance of the Pt catalyst for CO oxidation was investigated in detail. And the results were compared with those without SiO<sub>2</sub> overcoating layer. Investigations found that the SiO<sub>2</sub> coating layer effectively inhibited the sintering of Pt NPs at high temperatures, enhancing the thermal stability. In addition, the SiO<sub>2</sub> overcoating layer improved the catalytic activity of the Pt-based catalyst by inducing higher concentration of oxygen vacancies on the catalyst surface as well as weakening the CO adsorption, which could enhance the adsorption and activation ability of oxygen. Meanwhile, the presence of SiO<sub>2</sub> overcoating layer improved the catalytic stability during CO oxidation reaction. This work provides an important reference for the design and development of supported Pt-based catalysts with excellent thermal stability and catalytic activity for CO oxidation.</div></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":"100 ","pages":"Pages 36-44"},"PeriodicalIF":4.1,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Detailed assessment with sensitivity analysis of solid stress model in MP-PIC simulation for bubbling fluidized beds

IF 4.1 2区材料科学 Q2 ENGINEERING, CHEMICAL

Particuology

Pub Date : 2025-03-08 DOI: 10.1016/j.partic.2025.02.022

Chenxi Lu , Minmin Zhou , Hang Zhou , Jiwei Yao , Daoyin Liu , Yueming Wang , Lunbo Duan

Gas-solid granular flows are widely used in multiple industrial applications. The Multiphase Particle-In-Cell (MP-PIC) method is increasingly recognized for its capability to efficiently model these industrial-scale gas-solid granular flows. The solid stress model is crucial in MP-PIC method; however, its influence on the simulation results has not been thoroughly investigated. In this work, the pseudo-2D bubbling fluidized bed is modeled using MP-PIC method in OpenFOAM, in which the experiment operates at twice the minimum fluidization velocity condition using glass bead as the bed material. We primarily investigate the variation of the inter-particle solid stress values in the bed and its influence on the simulation results across a range of solid stress model parameters. The simulation results including bubble size, aspect ratio, and pressure drop and bed height, have been compared with the corresponding experimental data and empirical correlation. Sensitivity analysis narrows down the solid stress model parameter space and identify the most sensitive parameter is the close-packed volume fraction of particles. Results demonstrate that solid stress plays a significant role in dense particle flow, making particles more dispersed. Increasing solid stress reduces bubble size, aspect ratio, and pressure drop fluctuations, with minimal impact on bed height and average pressure drop. By comparing simulations and experiments, the optimal parameters of the model are determined. Moreover, the obtained optimal parameters effectively predict gas-solid flow across varying fluidization velocities and three-dimensional fluidized beds. This study provides a detailed analysis of solid stress effects, offering a more comprehensive understanding of the parameters for future MP-PIC simulations and validations.

{"title":"Detailed assessment with sensitivity analysis of solid stress model in MP-PIC simulation for bubbling fluidized beds","authors":"Chenxi Lu , Minmin Zhou , Hang Zhou , Jiwei Yao , Daoyin Liu , Yueming Wang , Lunbo Duan","doi":"10.1016/j.partic.2025.02.022","DOIUrl":"10.1016/j.partic.2025.02.022","url":null,"abstract":"<div><div>Gas-solid granular flows are widely used in multiple industrial applications. The Multiphase Particle-In-Cell (MP-PIC) method is increasingly recognized for its capability to efficiently model these industrial-scale gas-solid granular flows. The solid stress model is crucial in MP-PIC method; however, its influence on the simulation results has not been thoroughly investigated. In this work, the pseudo-2D bubbling fluidized bed is modeled using MP-PIC method in OpenFOAM, in which the experiment operates at twice the minimum fluidization velocity condition using glass bead as the bed material. We primarily investigate the variation of the inter-particle solid stress values in the bed and its influence on the simulation results across a range of solid stress model parameters. The simulation results including bubble size, aspect ratio, and pressure drop and bed height, have been compared with the corresponding experimental data and empirical correlation. Sensitivity analysis narrows down the solid stress model parameter space and identify the most sensitive parameter is the close-packed volume fraction of particles. Results demonstrate that solid stress plays a significant role in dense particle flow, making particles more dispersed. Increasing solid stress reduces bubble size, aspect ratio, and pressure drop fluctuations, with minimal impact on bed height and average pressure drop. By comparing simulations and experiments, the optimal parameters of the model are determined. Moreover, the obtained optimal parameters effectively predict gas-solid flow across varying fluidization velocities and three-dimensional fluidized beds. This study provides a detailed analysis of solid stress effects, offering a more comprehensive understanding of the parameters for future MP-PIC simulations and validations.</div></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":"99 ","pages":"Pages 226-242"},"PeriodicalIF":4.1,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Supratransmission phenomenon and the dissipation mechanism of stress wave in ordered granular material

IF 4.1 2区材料科学 Q2 ENGINEERING, CHEMICAL

Particuology

Pub Date : 2025-03-07 DOI: 10.1016/j.partic.2025.02.020

Zhe Wang , Jiao Wang , Xiangyu Li

Nonlinear Supratransmission refers to the sudden large energy flow when a harmonic driving reaches a threshold amplitude in a system at a given frequency. In this work, supratransmission of stress wave in two-dimension ordered granular material is investigated by the Discrete Element Method (DEM). The abrupt change in spectrum distribution of stress waves can be utilized as a criterion to identify the occurrence of the supratransmission phenomenon, in which, the Lower Forbidden Band, Pass Band and Upper Forbidden Band can be clearly distinguished in the spectrum distribution diagram. The influences of friction coefficient and prestress on spectrum distribution have been expounded. The longitudinal prestress shows strong ability in adjusting the upper forbidden bandwidth. Moreover, in some frequency bands, the energy transfer efficiency increases sharply with the increase of the friction coefficient. Then, the research focus turns to the dissipation mechanism of stress waves in granular materials. According to the intensity of energy dissipation, the dissipation band is defined, in which a large part of the energy is dissipated. The coupling of the response and excitation of the boundary particles plays an important role in dissipation of stress waves. Compared with other structures, the square-packed granular material has more significant effect on the dissipation of stress wave. The results will provide new insights into the wave propagation behavior of granular materials.

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引用次数: 0

Ordering and metastability in jamming structures of sphere packings

IF 4.1 2区材料科学 Q2 ENGINEERING, CHEMICAL

Particuology

Pub Date : 2025-03-07 DOI: 10.1016/j.partic.2025.02.021

Wei Fan , Ju Wang , Xizhong An , Yongli Wu , Yi Zou , Kejun Dong , Runyu Yang , Ruiping Zou , Aibing Yu

Metastability, disorder and jamming are the typical characteristics of amorphous systems, while the related structure changes remain unclear. Sphere packing is often used as a structure model for amorphous and crystalline states. In this article, sphere packing systems with packing densities ranging from 0.50 to 0.74 were simulated by using Discrete Element Method (DEM), and the obtained packing structures were assessed to investigate the densification process and jamming properties. An order parameter that can effectively distinguish the order and disorder of packing structures was proposed based on the distribution characteristics of jamming angles. Then the evolution of jamming characteristics during the transition from Random Loose Packing (RLP) to Random Close Packing (RCP) and the jamming-jamming relations of different packing structures were demonstrated. On this basis, a correlation between order-jamming-metastable states from the microscopic structural perspective was established, which is of valuable theoretical and practical implications for the characterization and synthesis of crystalline and amorphous materials.

{"title":"Ordering and metastability in jamming structures of sphere packings","authors":"Wei Fan , Ju Wang , Xizhong An , Yongli Wu , Yi Zou , Kejun Dong , Runyu Yang , Ruiping Zou , Aibing Yu","doi":"10.1016/j.partic.2025.02.021","DOIUrl":"10.1016/j.partic.2025.02.021","url":null,"abstract":"<div><div>Metastability, disorder and jamming are the typical characteristics of amorphous systems, while the related structure changes remain unclear. Sphere packing is often used as a structure model for amorphous and crystalline states. In this article, sphere packing systems with packing densities ranging from 0.50 to 0.74 were simulated by using Discrete Element Method (DEM), and the obtained packing structures were assessed to investigate the densification process and jamming properties. An order parameter that can effectively distinguish the order and disorder of packing structures was proposed based on the distribution characteristics of jamming angles. Then the evolution of jamming characteristics during the transition from Random Loose Packing (RLP) to Random Close Packing (RCP) and the jamming-jamming relations of different packing structures were demonstrated. On this basis, a correlation between order-jamming-metastable states from the microscopic structural perspective was established, which is of valuable theoretical and practical implications for the characterization and synthesis of crystalline and amorphous materials.</div></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":"99 ","pages":"Pages 128-139"},"PeriodicalIF":4.1,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143610910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0