Granular filtration beds offer promising potential due to their high dust removal efficiency, temperature resistance, and pressure tolerance. This study employed the CFD-DEM method to model mixed-structure and double-layer granular beds, investigating the effects of bed structure, filter media ratio, and gas velocity on filtration efficiency and pressure drop. Results revealed that the mixed-structure exhibited superior graded dust removal efficiency within the simulated range, identifying a critical particle size: efficiency was 3 %–6 % higher for particles below this size, diminishing to only 1.5 %–2.7 % higher for larger particles. This structural advantage weakened with increasing gas velocity, becoming negligible above 0.4 m/s. Furthermore, two transition particle sizes were identified for the mixed-structure regarding velocity sensitivity; efficiency for fine particles between these sizes was significantly enhanced by velocity (up to 30 % improvement), while particles outside this range were minimally affected. Comprehensive evaluation using the Stokes number (Stk) showed efficiency increased with Stk across three distinct regions (stable, rapid growth, slow growth), with the inter-region thresholds shifting toward lower Stk values as the proportion of 2-mm media increased.
{"title":"CFD-DEM simulation and mechanism analysis of filtration performance in polydisperse granular beds","authors":"Shibo Gao , Dongsheng Jiao , Daotong Li , Xinyu Gao , Liangzhi Xia","doi":"10.1016/j.powtec.2025.121937","DOIUrl":"10.1016/j.powtec.2025.121937","url":null,"abstract":"<div><div>Granular filtration beds offer promising potential due to their high dust removal efficiency, temperature resistance, and pressure tolerance. This study employed the CFD-DEM method to model mixed-structure and double-layer granular beds, investigating the effects of bed structure, filter media ratio, and gas velocity on filtration efficiency and pressure drop. Results revealed that the mixed-structure exhibited superior graded dust removal efficiency within the simulated range, identifying a critical particle size: efficiency was 3 %–6 % higher for particles below this size, diminishing to only 1.5 %–2.7 % higher for larger particles. This structural advantage weakened with increasing gas velocity, becoming negligible above 0.4 m/s. Furthermore, two transition particle sizes were identified for the mixed-structure regarding velocity sensitivity; efficiency for fine particles between these sizes was significantly enhanced by velocity (up to 30 % improvement), while particles outside this range were minimally affected. Comprehensive evaluation using the Stokes number (S<sub>tk</sub>) showed efficiency increased with S<sub>tk</sub> across three distinct regions (stable, rapid growth, slow growth), with the inter-region thresholds shifting toward lower S<sub>tk</sub> values as the proportion of 2-mm media increased.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"469 ","pages":"Article 121937"},"PeriodicalIF":4.6,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The heat-resistant ultrafine potassium aluminum carbonate hydroxide KAl(OH)₂CO₃ (UKDW) dry powder fire extinguishing agent with hydrophobic and oleophobic properties has potential application prospect in large class B oil fires such as aircraft fires. In this study, the surface modification of UKDW was carried out by sol-gel method, and the environmentally friendly functional fluorosilane structure was introduced to obtain hydrophobic and oleophobic modified products (UKDW-FSi). The modification efficacy of UKDW-FSi under different formulation conditions was systematically investigated, with characterization of its microstructure, chemical composition, flow properties, hydrophobicity/oleophobicity, fire extinguishing performance, and resistance to reignition. Results indicate that the modified UKDW-FSi exhibits water contact angle (WCA) and oil contact angle (OCA) of 152.819° and 149.158°, respectively, demonstrating excellent hydrophobic and oleophobic properties. Simultaneously, the modified UKDW-FSi exhibited enhanced flowability, extinguishing aviation kerosene fires within 2.64 s，faster than the unmodified UKDW(2.90 s), while demonstrating anti-reignition ability with a delay time of 16.5 s. Furthermore, its outstanding thermal stability and hydrophobicity ensure long-term stable storage and application potential in complex environments such as aircraft equipment compartments.
{"title":"Surface modification and application properties of heat-resistant ultrafine KAl(OH)₂CO₃ dry powder fire extinguishing agent","authors":"Lirong Liu, Lanke Liu, Jinglong Huang, Renming Pan, Xia Zhou","doi":"10.1016/j.powtec.2025.121935","DOIUrl":"10.1016/j.powtec.2025.121935","url":null,"abstract":"<div><div>The heat-resistant ultrafine potassium aluminum carbonate hydroxide KAl(OH)₂CO₃ (UKDW) dry powder fire extinguishing agent with hydrophobic and oleophobic properties has potential application prospect in large class B oil fires such as aircraft fires. In this study, the surface modification of UKDW was carried out by sol-gel method, and the environmentally friendly functional fluorosilane structure was introduced to obtain hydrophobic and oleophobic modified products (UKDW-FSi). The modification efficacy of UKDW-FSi under different formulation conditions was systematically investigated, with characterization of its microstructure, chemical composition, flow properties, hydrophobicity/oleophobicity, fire extinguishing performance, and resistance to reignition. Results indicate that the modified UKDW-FSi exhibits water contact angle (WCA) and oil contact angle (OCA) of 152.819° and 149.158°, respectively, demonstrating excellent hydrophobic and oleophobic properties. Simultaneously, the modified UKDW-FSi exhibited enhanced flowability, extinguishing aviation kerosene fires within 2.64 s，faster than the unmodified UKDW(2.90 s), while demonstrating anti-reignition ability with a delay time of 16.5 s. Furthermore, its outstanding thermal stability and hydrophobicity ensure long-term stable storage and application potential in complex environments such as aircraft equipment compartments.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"469 ","pages":"Article 121935"},"PeriodicalIF":4.6,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145620195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-19DOI: 10.1016/j.powtec.2025.121912
N.C. Stevens , A. Dolai , C.J.M. Hessels , N.G. Deen , G. Finotello
Hydrogen-based reduction of iron oxides offers a promising, low-carbon alternative to hydrocarbon fuels in steel production and plays a critical role in the Iron Power Cycle, an emerging technology for renewable energy storage and transport. However, despite its practical significance, research on hydrogen reduction in the presence of water vapor remains limited, especially for high-purity, micron-sized iron oxide powders produced from iron combustion. In this study, we investigate the reduction kinetics of combusted iron powder using thermogravimetric analysis (TGA) at three temperatures: 500 C, 700 C and 800 C and partial pressure ratios () ranging from 0.0 to 0.7. The results indicate that the conversion rate increases with temperature, and water vapor hinders the reduction process, particularly at lower temperatures. This emphasizes the necessity of removing water vapor during iron oxide reduction to guarantee high conversion. The reduction process is divided into distinct phases, with rate-limiting mechanisms in each phase analyzed using the Avrami constant (). Kinetic parameters, including activation energy () and the overall water vapor reaction order (), are determined using the isoconversional method. We propose a modified multi-step kinetic model to extract the rate constant (), Avrami constant (), and water vapor reaction order () for each step of the reduction pathway. The results are crucial for optimizing hydrogen-based ironmaking processes in sustainable steel production and for the Iron Power Cycle.
{"title":"Hydrogen reduction of combusted iron powder: Role of water vapor in reaction kinetics","authors":"N.C. Stevens , A. Dolai , C.J.M. Hessels , N.G. Deen , G. Finotello","doi":"10.1016/j.powtec.2025.121912","DOIUrl":"10.1016/j.powtec.2025.121912","url":null,"abstract":"<div><div>Hydrogen-based reduction of iron oxides offers a promising, low-carbon alternative to hydrocarbon fuels in steel production and plays a critical role in the Iron Power Cycle, an emerging technology for renewable energy storage and transport. However, despite its practical significance, research on hydrogen reduction in the presence of water vapor remains limited, especially for high-purity, micron-sized iron oxide powders produced from iron combustion. In this study, we investigate the reduction kinetics of combusted iron powder using thermogravimetric analysis (TGA) at three temperatures: 500 <span><math><mo>°</mo></math></span>C, 700 <span><math><mo>°</mo></math></span>C and 800 <span><math><mo>°</mo></math></span>C and partial pressure ratios (<span><math><mrow><mi>Δ</mi><msub><mrow><mi>P</mi></mrow><mrow><msub><mrow><mtext>H</mtext></mrow><mrow><mn>2</mn></mrow></msub><mtext>O</mtext></mrow></msub><mo>/</mo><mi>Δ</mi><msub><mrow><mi>P</mi></mrow><mrow><msub><mrow><mtext>H</mtext></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub></mrow></math></span>) ranging from 0.0 to 0.7. The results indicate that the conversion rate increases with temperature, and water vapor hinders the reduction process, particularly at lower temperatures. This emphasizes the necessity of removing water vapor during iron oxide reduction to guarantee high conversion. The reduction process is divided into distinct phases, with rate-limiting mechanisms in each phase analyzed using the Avrami constant (<span><math><mi>n</mi></math></span>). Kinetic parameters, including activation energy (<span><math><msub><mrow><mi>E</mi></mrow><mrow><mtext>a</mtext></mrow></msub></math></span>) and the overall water vapor reaction order (<span><math><mi>m</mi></math></span>), are determined using the isoconversional method. We propose a modified multi-step kinetic model to extract the rate constant (<span><math><msub><mrow><mi>k</mi></mrow><mrow><mtext>app</mtext></mrow></msub></math></span>), Avrami constant (<span><math><mi>n</mi></math></span>), and water vapor reaction order (<span><math><mi>m</mi></math></span>) for each step of the reduction pathway. The results are crucial for optimizing hydrogen-based ironmaking processes in sustainable steel production and for the Iron Power Cycle.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"469 ","pages":"Article 121912"},"PeriodicalIF":4.6,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-19DOI: 10.1016/j.powtec.2025.121945
Abdul Haseeb Lodhi , Hafiz Hamza Riaz , Muhammad Hamza Ali , Adnan Munir , Ming Zhao , Mohammad S. Islam , Kamal Dua , Keshav Raj Paudel
Human metapneumovirus (hMPV) is a re-emerging pathogen implicated in severe respiratory illnesses worldwide. Effective management of hMPV outbreaks relies on understanding how viral particles behave within human pulmonary airways. This study utilizes computed tomography-derived airway models and advanced computational fluid dynamics to investigate the transport and deposition of hMPV-like particles across fifteen airway generations under physiologically representative breathing conditions. The effects of viral particle size and morphology, together with dynamic inhalation–exhalation cycles, are systematically analysed. Results highlight distinct deposition hotspots for cylindrical versus spherical particles, with pronounced differences between inhalation and exhalation phases and notable sensitivity to breathing flow rate. The observed deposition trends provide new insight into shape- and phase-dependent risk regions likely to influence infection patterns and guide aerosolized therapy design. By addressing previously neglected aspects of non-spherical particle transport and transient airflow, this work advances the quantitative modelling of airborne viral pathogen exposure in the human respiratory system.
{"title":"Computational analysis of human metapneumovirus particle behaviour in the pulmonary system","authors":"Abdul Haseeb Lodhi , Hafiz Hamza Riaz , Muhammad Hamza Ali , Adnan Munir , Ming Zhao , Mohammad S. Islam , Kamal Dua , Keshav Raj Paudel","doi":"10.1016/j.powtec.2025.121945","DOIUrl":"10.1016/j.powtec.2025.121945","url":null,"abstract":"<div><div>Human metapneumovirus (hMPV) is a re-emerging pathogen implicated in severe respiratory illnesses worldwide. Effective management of hMPV outbreaks relies on understanding how viral particles behave within human pulmonary airways. This study utilizes computed tomography-derived airway models and advanced computational fluid dynamics to investigate the transport and deposition of hMPV-like particles across fifteen airway generations under physiologically representative breathing conditions. The effects of viral particle size and morphology, together with dynamic inhalation–exhalation cycles, are systematically analysed. Results highlight distinct deposition hotspots for cylindrical versus spherical particles, with pronounced differences between inhalation and exhalation phases and notable sensitivity to breathing flow rate. The observed deposition trends provide new insight into shape- and phase-dependent risk regions likely to influence infection patterns and guide aerosolized therapy design. By addressing previously neglected aspects of non-spherical particle transport and transient airflow, this work advances the quantitative modelling of airborne viral pathogen exposure in the human respiratory system.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"469 ","pages":"Article 121945"},"PeriodicalIF":4.6,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-19DOI: 10.1016/j.powtec.2025.121936
Jingui Wang , Chensheng Lin , Jianhao Wei , Yuchen Ke , Su Zhang
<div><div>Polypropylene (<span><math><mi>PP</mi></math></span>) dust presents a material explosion hazard during handling. We quantify the suppression efficacy and mechanisms of neat “dry water” (DW; micronized water encapsulated by hydrophobic silica) and two modified variants—monoammonium phosphate DW (<span><math><mi>MAP</mi><mo>−</mo><mi>DW</mi><mo>,</mo><mi>NH</mi><mo>₄</mo><mi>H</mi><mo>₂</mo><mi>PO</mi><mo>₄</mo></math></span>) and potassium hydrogen carbonate <span><math><mi>DW</mi></math></span> (<span><math><mi>KHCO</mi><mo>₃</mo><mo>−</mo><mi>DW</mi></math></span>). Tests were performed in a <span><math><mn>20</mn><mspace></mspace><mi>L</mi></math></span> spherical vessel (<span><math><mi>EN</mi><mspace></mspace><mn>14034</mn><mo>−</mo><mn>2</mn></math></span>) across four particle sizes (<span><math><mn>10</mn><mo>/</mo><mn>30</mn><mo>/</mo><mn>60</mn><mo>/</mo><mn>140</mn><mspace></mspace><mi>μm</mi></math></span>) and from lean to fuel-rich dust concentrations. Both maximum explosion pressure <span><math><mo>(</mo><msub><mi>P</mi><mi>max</mi></msub></math></span>)and maximum pressure-rise rate (<span><math><msub><mfenced><mrow><mi>d</mi><mi>p</mi><mo>/</mo><mi>d</mi><mi>t</mi></mrow></mfenced><mi>max</mi></msub><mo>)</mo></math></span> showed unimodal dependence on concentration; for <span><math><mn>10</mn><mspace></mspace><mi>μm</mi><mspace></mspace><mi>PP</mi></math></span>, <span><math><msub><mi>P</mi><mi>max</mi></msub></math></span> was <span><math><mo>≈</mo><mn>0.68</mn><mspace></mspace><mi>MPa</mi><mspace></mspace></math></span> at <span><math><mi>ρ</mi><mo>≈</mo><mn>300</mn><mspace></mspace><mi>g</mi><mo>·</mo><msup><mi>m</mi><mrow><mo>−</mo><mn>3</mn></mrow></msup></math></span> (St-1). Under near-optimal <span><math><mi>PP</mi></math></span> baselines, dose–response assays parameterized by the dosage ratio <span><math><mi>φ</mi></math></span> showed consistent ranking <span><math><mi>KHCO</mi><mo>₃</mo><mo>−</mo><mi>DW</mi><mo>></mo><mi>MAP</mi><mo>−</mo><mi>DW</mi><mo>></mo><mi>DW</mi></math></span>. All formulations reduced <span><math><msub><mi>P</mi><mi>max</mi></msub></math></span> and <span><math><msub><mfenced><mrow><mi>d</mi><mi>p</mi><mo>/</mo><mi>d</mi><mi>t</mi></mrow></mfenced><mi>max</mi></msub></math></span> while delaying pressure-rise dynamics, and the <span><math><mn>15</mn><mspace></mspace><mi>wt</mi><mo>%</mo></math></span> KHCO₃ system (<span><math><mi>KH</mi><mo>−</mo><mn>15</mn></math></span>) achieved <span><math><mo>></mo><mn>80</mn><mo>%</mo></math></span> reduction in <span><math><msub><mi>P</mi><mi>max</mi></msub></math></span> at <span><math><mi>φ</mi><mo>≈</mo><mn>1.2</mn></math></span>, driving <span><math><msub><mi>K</mi><mi>st</mi></msub></math></span> <!--> toward St-0. a slight increase in rate was occasionally observed at very low <span><math><mi>φ</mi></math></span>, likely due to enhanced cloud dispersion. Mechanistic diagnostics coupled TG–FTIR–MS with TG–DSC. Neat <span><math
{"title":"Effect of modified dry water on the explosion characteristics of polypropylene dust","authors":"Jingui Wang , Chensheng Lin , Jianhao Wei , Yuchen Ke , Su Zhang","doi":"10.1016/j.powtec.2025.121936","DOIUrl":"10.1016/j.powtec.2025.121936","url":null,"abstract":"<div><div>Polypropylene (<span><math><mi>PP</mi></math></span>) dust presents a material explosion hazard during handling. We quantify the suppression efficacy and mechanisms of neat “dry water” (DW; micronized water encapsulated by hydrophobic silica) and two modified variants—monoammonium phosphate DW (<span><math><mi>MAP</mi><mo>−</mo><mi>DW</mi><mo>,</mo><mi>NH</mi><mo>₄</mo><mi>H</mi><mo>₂</mo><mi>PO</mi><mo>₄</mo></math></span>) and potassium hydrogen carbonate <span><math><mi>DW</mi></math></span> (<span><math><mi>KHCO</mi><mo>₃</mo><mo>−</mo><mi>DW</mi></math></span>). Tests were performed in a <span><math><mn>20</mn><mspace></mspace><mi>L</mi></math></span> spherical vessel (<span><math><mi>EN</mi><mspace></mspace><mn>14034</mn><mo>−</mo><mn>2</mn></math></span>) across four particle sizes (<span><math><mn>10</mn><mo>/</mo><mn>30</mn><mo>/</mo><mn>60</mn><mo>/</mo><mn>140</mn><mspace></mspace><mi>μm</mi></math></span>) and from lean to fuel-rich dust concentrations. Both maximum explosion pressure <span><math><mo>(</mo><msub><mi>P</mi><mi>max</mi></msub></math></span>)and maximum pressure-rise rate (<span><math><msub><mfenced><mrow><mi>d</mi><mi>p</mi><mo>/</mo><mi>d</mi><mi>t</mi></mrow></mfenced><mi>max</mi></msub><mo>)</mo></math></span> showed unimodal dependence on concentration; for <span><math><mn>10</mn><mspace></mspace><mi>μm</mi><mspace></mspace><mi>PP</mi></math></span>, <span><math><msub><mi>P</mi><mi>max</mi></msub></math></span> was <span><math><mo>≈</mo><mn>0.68</mn><mspace></mspace><mi>MPa</mi><mspace></mspace></math></span> at <span><math><mi>ρ</mi><mo>≈</mo><mn>300</mn><mspace></mspace><mi>g</mi><mo>·</mo><msup><mi>m</mi><mrow><mo>−</mo><mn>3</mn></mrow></msup></math></span> (St-1). Under near-optimal <span><math><mi>PP</mi></math></span> baselines, dose–response assays parameterized by the dosage ratio <span><math><mi>φ</mi></math></span> showed consistent ranking <span><math><mi>KHCO</mi><mo>₃</mo><mo>−</mo><mi>DW</mi><mo>></mo><mi>MAP</mi><mo>−</mo><mi>DW</mi><mo>></mo><mi>DW</mi></math></span>. All formulations reduced <span><math><msub><mi>P</mi><mi>max</mi></msub></math></span> and <span><math><msub><mfenced><mrow><mi>d</mi><mi>p</mi><mo>/</mo><mi>d</mi><mi>t</mi></mrow></mfenced><mi>max</mi></msub></math></span> while delaying pressure-rise dynamics, and the <span><math><mn>15</mn><mspace></mspace><mi>wt</mi><mo>%</mo></math></span> KHCO₃ system (<span><math><mi>KH</mi><mo>−</mo><mn>15</mn></math></span>) achieved <span><math><mo>></mo><mn>80</mn><mo>%</mo></math></span> reduction in <span><math><msub><mi>P</mi><mi>max</mi></msub></math></span> at <span><math><mi>φ</mi><mo>≈</mo><mn>1.2</mn></math></span>, driving <span><math><msub><mi>K</mi><mi>st</mi></msub></math></span> <!--> toward St-0. a slight increase in rate was occasionally observed at very low <span><math><mi>φ</mi></math></span>, likely due to enhanced cloud dispersion. Mechanistic diagnostics coupled TG–FTIR–MS with TG–DSC. Neat <span><math","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"469 ","pages":"Article 121936"},"PeriodicalIF":4.6,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-19DOI: 10.1016/j.powtec.2025.121932
Yangzhen Gao , Liang Han , Yan Meng , Guancheng Dong , Jian Zhang
Enhancing sorting accuracy for municipal solid waste (MSW) is a key objective in waste management. In disc screens, sorting outcomes are determined by material motion in the discharge region, where kinematic mechanisms remain insufficiently understood. This study investigates the transport behavior of board-like particles and spherical particles using high-speed imaging and trajectory analysis. While both materials exhibit ballistic superdiffusion driven by rotating discs, spherical particles experience significantly greater trajectory variability due to strong perturbations near the disc shafts. Despite similar average path straightness, spherical particles exhibit a strongly positively skewed distribution, indicating that a few extreme tumbling events drive their motion instability and increase misclassification risk. Material properties and dimensions further modulate transport behavior: low-density foam boards have higher velocities, and aspect ratio significantly affects residence time. In contrast, large wood spheres exhibit greater transport instability, leading to prolonged retention in the discharge zone. These findings reveal the intrinsic relationship between particle shape, trajectory variability, and sorting behavior in disc screens, offering theoretical support for structural optimization and control parameter tuning. They also provide practical insights for improving material recovery facility (MRF) performance, reducing sorting errors, and supporting sustainable MSW management and circular economy goals.
{"title":"Comparative kinematic behavior of board-like particles and spherical particles in the disc screen discharge region","authors":"Yangzhen Gao , Liang Han , Yan Meng , Guancheng Dong , Jian Zhang","doi":"10.1016/j.powtec.2025.121932","DOIUrl":"10.1016/j.powtec.2025.121932","url":null,"abstract":"<div><div>Enhancing sorting accuracy for municipal solid waste (MSW) is a key objective in waste management. In disc screens, sorting outcomes are determined by material motion in the discharge region, where kinematic mechanisms remain insufficiently understood. This study investigates the transport behavior of board-like particles and spherical particles using high-speed imaging and trajectory analysis. While both materials exhibit ballistic superdiffusion driven by rotating discs, spherical particles experience significantly greater trajectory variability due to strong perturbations near the disc shafts. Despite similar average path straightness, spherical particles exhibit a strongly positively skewed distribution, indicating that a few extreme tumbling events drive their motion instability and increase misclassification risk. Material properties and dimensions further modulate transport behavior: low-density foam boards have higher velocities, and aspect ratio significantly affects residence time. In contrast, large wood spheres exhibit greater transport instability, leading to prolonged retention in the discharge zone. These findings reveal the intrinsic relationship between particle shape, trajectory variability, and sorting behavior in disc screens, offering theoretical support for structural optimization and control parameter tuning. They also provide practical insights for improving material recovery facility (MRF) performance, reducing sorting errors, and supporting sustainable MSW management and circular economy goals.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"469 ","pages":"Article 121932"},"PeriodicalIF":4.6,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145620201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-19DOI: 10.1016/j.powtec.2025.121947
Asif Khan , Carlo S. Iorio , Mehdi Feizpour , Andrey Glushchuk
An alternative approach of graphene implementation inside a porous structure has been presented. It consists of three stages: (I) preparation of a graphene ink–binder combination; (II) incorporation of graphene inside a porous medium; and (III) co-sintering of graphene within pores. The technique was verified for nickel and stainless steel 316 L materials. The presence of graphene was confirmed by Raman spectroscopy in both cases after co-sintering. The alloy material showed improved performance that positively affected the overall flow dynamics. A significant increase in permeability, with a 60 % improvement over uncoated variants, was obtained along with a reduction in capillary pressure.
{"title":"Incorporation of graphene into metallic porous media via co-sintering technique: Impact on capillary pressure, porosity and permeability","authors":"Asif Khan , Carlo S. Iorio , Mehdi Feizpour , Andrey Glushchuk","doi":"10.1016/j.powtec.2025.121947","DOIUrl":"10.1016/j.powtec.2025.121947","url":null,"abstract":"<div><div>An alternative approach of graphene implementation inside a porous structure has been presented. It consists of three stages: (I) preparation of a graphene ink–binder combination; (II) incorporation of graphene inside a porous medium; and (III) co-sintering of graphene within pores. The technique was verified for nickel and stainless steel 316 L materials. The presence of graphene was confirmed by Raman spectroscopy in both cases after co-sintering. The alloy material showed improved performance that positively affected the overall flow dynamics. A significant increase in permeability, with a 60 % improvement over uncoated variants, was obtained along with a reduction in capillary pressure.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"469 ","pages":"Article 121947"},"PeriodicalIF":4.6,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-19DOI: 10.1016/j.powtec.2025.121941
Chuang Zhao , Peng Zhang , Li Bao , Chengbo Li
The study of the dynamic properties of granular materials during uniaxial compression provides insights into the macro-micro mechanical relationships of the system, and has been a focus of research. In this study, the uniaxial compression process of super-ellipsoid systems with different packing structures is simulated using the discrete element method. The proposed characterization theory for non-spherical particle structures is applied to calculate the evolution of packing structures during compression. The influence of shear-induced anisotropy on the elastic moduli is then computed and discussed. The results show that different packing structures significantly affect the elastic modulus of the system, and that for systems with the same packing structure, the volume fraction, coordination number, and elastic modulus decrease as compression progresses. To verify the change in elastic modulus, the propagation of elastic waves within the system is simulated, and the compression and shear wave velocities are calculated using the time-of-flight method. The variation in elastic modulus during compression is further confirmed from the perspective of changes in wave velocities. The particle packing structure characterization method used in this study is universal and applicable to the decomposition of irreducible super-tensor bases in any dimension. This approach has both practical value in engineering computations and theoretical significance.
{"title":"The effect of particle packing structure on the dynamic properties of super-ellipsoid systems during uniaxial compression","authors":"Chuang Zhao , Peng Zhang , Li Bao , Chengbo Li","doi":"10.1016/j.powtec.2025.121941","DOIUrl":"10.1016/j.powtec.2025.121941","url":null,"abstract":"<div><div>The study of the dynamic properties of granular materials during uniaxial compression provides insights into the macro-micro mechanical relationships of the system, and has been a focus of research. In this study, the uniaxial compression process of super-ellipsoid systems with different packing structures is simulated using the discrete element method. The proposed characterization theory for non-spherical particle structures is applied to calculate the evolution of packing structures during compression. The influence of shear-induced anisotropy on the elastic moduli is then computed and discussed. The results show that different packing structures significantly affect the elastic modulus of the system, and that for systems with the same packing structure, the volume fraction, coordination number, and elastic modulus decrease as compression progresses. To verify the change in elastic modulus, the propagation of elastic waves within the system is simulated, and the compression and shear wave velocities are calculated using the time-of-flight method. The variation in elastic modulus during compression is further confirmed from the perspective of changes in wave velocities. The particle packing structure characterization method used in this study is universal and applicable to the decomposition of irreducible super-tensor bases in any dimension. This approach has both practical value in engineering computations and theoretical significance.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"469 ","pages":"Article 121941"},"PeriodicalIF":4.6,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145620302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-19DOI: 10.1016/j.powtec.2025.121926
Alireza Bahramian , Martin Olazar
The dependence of powder flowability on particle size distribution (PSD) at different flow regimes offers new insights for a better understanding of the nanoparticle (NP) agglomeration mechanisms, which could not be recognized in detail by experiments. This study aims to evaluate the validity of collision models for the estimation of the PSD of titania NP agglomerates in a conical fluidized bed. A combination of fragile primary simple-agglomerates (∼10-70 μm) and secondary types (∼70-100 μm) was experimentally identified in the turbulent flow regime, while rigid complex-agglomerates (∼100-150 μm) were mainly formed in the partially fluidized regime. A narrow-cut PSD was observed in the spout zone, where the mean agglomerate size was approximately three times smaller than in the annular zone. CFD-DEM simulations using the adhesive Hertz-Mindlin and Johnson-Kendall-Roberts (HM-JKR) model and the linear spring-dashpot (LSD) model have been applied to adjust particle collision parameters and collision model variables. The restitution coefficient noticeably affects the particle breakage rate in the partially fluidized regime, while the coefficients of friction and wall specularity affect the agglomeration rate in the turbulent flow. The collision frequency was more influenced by the LSD model than by HM-JKR, and its magnitude was greater in the turbulent flow than in the partially fluidized regime. The agglomerate frequency is highly affected by the magnitude of the cohesive force, with Gaussian-type and narrow-cut PSDs being predicted by applying strong and weak cohesive forces, respectively. The HM-JKR model shows better agreement with the experimental data than the LSD model in turbulent flow, whereas the LSD model provides more accurate results in partially fluidized conditions.
{"title":"Effect of flow regimes on flowability of titania nanoparticle agglomerates and particle size distribution in a conical fluidized bed: evaluation of particle collision parameters and collision models","authors":"Alireza Bahramian , Martin Olazar","doi":"10.1016/j.powtec.2025.121926","DOIUrl":"10.1016/j.powtec.2025.121926","url":null,"abstract":"<div><div>The dependence of powder flowability on particle size distribution (PSD) at different flow regimes offers new insights for a better understanding of the nanoparticle (NP) agglomeration mechanisms, which could not be recognized in detail by experiments. This study aims to evaluate the validity of collision models for the estimation of the PSD of titania NP agglomerates in a conical fluidized bed. A combination of fragile primary simple-agglomerates (∼10-70 μm) and secondary types (∼70-100 μm) was experimentally identified in the turbulent flow regime, while rigid complex-agglomerates (∼100-150 μm) were mainly formed in the partially fluidized regime. A narrow-cut PSD was observed in the spout zone, where the mean agglomerate size was approximately three times smaller than in the annular zone. CFD-DEM simulations using the adhesive Hertz-Mindlin and Johnson-Kendall-Roberts (HM-JKR) model and the linear spring-dashpot (LSD) model have been applied to adjust particle collision parameters and collision model variables. The restitution coefficient noticeably affects the particle breakage rate in the partially fluidized regime, while the coefficients of friction and wall specularity affect the agglomeration rate in the turbulent flow. The collision frequency was more influenced by the LSD model than by HM-JKR, and its magnitude was greater in the turbulent flow than in the partially fluidized regime. The agglomerate frequency is highly affected by the magnitude of the cohesive force, with Gaussian-type and narrow-cut PSDs being predicted by applying strong and weak cohesive forces, respectively. The HM-JKR model shows better agreement with the experimental data than the LSD model in turbulent flow, whereas the LSD model provides more accurate results in partially fluidized conditions.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"470 ","pages":"Article 121926"},"PeriodicalIF":4.6,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-19DOI: 10.1016/j.powtec.2025.121914
Weiwei Wang , Mingchun Yang , Wenbing Shi , Xue An , Shun Zhang , Ce Liu , Lichao Liu , Quan Zheng , Liqing Chen
In order to enhance the unsteady control of wheat seed flow in the conveying tube and achieve instantaneous stable and accurate seeding quantity of each row, the pressurized seed supply device has been optimized and designed to improve distribution characteristics and performance of the pneumatic centralized wheat seeding system. The CFD-DEM coupling method was used to simulate and analyze the influence of the pressure distribution and seed motion in the tube on the coefficient of variation of instantaneous seeding quantity and the coefficient of variation of inter-row instantaneous seeding quantity difference under the structure and working parameters. Bench tests were designed to verify the simulation results. Through response surface analysis, the optimal seeding performance was achieved at a inclined feeding section angle of 40°, inclined feeding section height of 16 mm, and airflow velocity of 30 m/s, resulting in the coefficient of variation of instantaneous seeding quantity on the seed feeding device is 3.82 %, and the coefficient of variation of inter-row instantaneous seeding quantity difference is 4.54 %. Bench test results unveiled that, under the optimal parameter combination, with the rotation speed of the seed supply spindle controlled at 20–60 rpm, the coefficient of variation of instantaneous seeding quantity on the seed supply device is less than 5.0 %, the coefficient of variation of inter-row instantaneous seeding quantity difference is less than 5.6 %, and the seed damage rate is less than 0.15 %, which meets the agronomic requirements of wheat seeding. This research provides valuable references for optimizing the design of pneumatic centralized wheat metering device and improving the uniformity of wheat seeding.
{"title":"A coupled simulation computational model for evaluating the seeds movement and airflow distribution characteristics in pneumatic centralized wheat metering device","authors":"Weiwei Wang , Mingchun Yang , Wenbing Shi , Xue An , Shun Zhang , Ce Liu , Lichao Liu , Quan Zheng , Liqing Chen","doi":"10.1016/j.powtec.2025.121914","DOIUrl":"10.1016/j.powtec.2025.121914","url":null,"abstract":"<div><div>In order to enhance the unsteady control of wheat seed flow in the conveying tube and achieve instantaneous stable and accurate seeding quantity of each row, the pressurized seed supply device has been optimized and designed to improve distribution characteristics and performance of the pneumatic centralized wheat seeding system. The CFD-DEM coupling method was used to simulate and analyze the influence of the pressure distribution and seed motion in the tube on the coefficient of variation of instantaneous seeding quantity and the coefficient of variation of inter-row instantaneous seeding quantity difference under the structure and working parameters. Bench tests were designed to verify the simulation results. Through response surface analysis, the optimal seeding performance was achieved at a inclined feeding section angle of 40°, inclined feeding section height of 16 mm, and airflow velocity of 30 m/s, resulting in the coefficient of variation of instantaneous seeding quantity on the seed feeding device is 3.82 %, and the coefficient of variation of inter-row instantaneous seeding quantity difference is 4.54 %. Bench test results unveiled that, under the optimal parameter combination, with the rotation speed of the seed supply spindle controlled at 20–60 rpm, the coefficient of variation of instantaneous seeding quantity on the seed supply device is less than 5.0 %, the coefficient of variation of inter-row instantaneous seeding quantity difference is less than 5.6 %, and the seed damage rate is less than 0.15 %, which meets the agronomic requirements of wheat seeding. This research provides valuable references for optimizing the design of pneumatic centralized wheat metering device and improving the uniformity of wheat seeding.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"469 ","pages":"Article 121914"},"PeriodicalIF":4.6,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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