Powder Technology最新文献

{"title":"CFD-DEM modeling of fluidized bed granulator: Granule formation, identification, and evolution of granule size distribution","authors":"Akanksha Rajput ,&nbsp;Jayanta Chakraborty ,&nbsp;Jitendra Kumar ,&nbsp;Anurag Tripathi","doi":"10.1016/j.powtec.2025.121726","DOIUrl":"10.1016/j.powtec.2025.121726","url":null,"abstract":"<div><div>The present study adopts a CFD-DEM coupled approach for modeling the wet granulation in a sparse pseudo-2D fluidized bed of dry and wet spherical particles. The granules formed through particle interactions are quantified using a novel granule identification algorithm, by accounting for the particle curing period and the surface liquid content. The identified granules are replaced by a multi-sphere model to incorporate the effect of granule strengthening due to drying of the liquid bridge. The temporal evolution of granule size distribution is analyzed, and the effects of key process parameters, including superficial gas velocity, liquid binder properties (such as liquid content, viscosity, and surface tension), and curing period, are investigated. Among various factors explored, the liquid binder surface tension and superficial gas velocity are found to be the strongest factors. Viscosity does not seem to play a significant role, possibly due to the use of coarse-grained particles.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"469 ","pages":"Article 121726"},"PeriodicalIF":4.6,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145322410","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}

{"title":"Oxidation mechanism of single char particles: Insights from chemical imaging by micro-Raman mapping technique in a heating stage","authors":"Ming Jiang ,&nbsp;Jun Xu ,&nbsp;Yuming Ding ,&nbsp;Kai Xu ,&nbsp;Long Jiang ,&nbsp;Yi Wang ,&nbsp;Sheng Su ,&nbsp;Song Hu ,&nbsp;Jun Xiang","doi":"10.1016/j.powtec.2025.121724","DOIUrl":"10.1016/j.powtec.2025.121724","url":null,"abstract":"<div><h3>Abstract</h3><div>This study developed a Raman-mapping method to visualize individual char particles during oxidation, tracking the spatiotemporal evolution of their chemical structure. 3 series of experiments were conducted: (i) micro-scale mapping of 1000 °C chars before oxidation to quantify inherent heterogeneity of the char particles, (ii) Raman mapping at room temperature after stepwise oxidation to resolve the progressive structural evolution during the char oxidation, and (iii) high-temperature in situ Raman spectroscopy of single char particle and char particle clusters to follow real-time carbon framework evolution and functional group formation during the oxidation sequence. The results show that Hongshaquan coal char pyrolyzed at 1000 °C exhibits intra- and inter-particle structural variation, with individual heterogeneity peaking when the particle's average structure approaches that of the bulk char. Besides, oxidation reactivity of the char correlates more strongly with char surface heterogeneity than with average structural parameters. During the char oxidation, its structures proceed in 3 stages: (i) O₂ attacks side chains and small aromatic rings, cleaving large aromatic rings and raising the fraction of oxygen-containing functional groups and small aromatic rings. (ii) These species accumulate to a peak and then deplete. (iii) A mineral-rich ash shell forms in the later stage of the oxidation, hindering oxygen diffusion and slowing down the oxidation of residual carbon. Single-particle oxidation results can capture the complete oxidation process and its chemical structure evolution, whereas particle clusters burn layer-by-layer, easily overlooking the early activation process. This study can provide a deep understanding on the oxidation mechanism of char single-particles.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"469 ","pages":"Article 121724"},"PeriodicalIF":4.6,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264599","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}

{"title":"Effect of La2O3 addition on preparation of ultrafine tungsten powder and its sintering densification behavior","authors":"Peng-Cheng Cai ,&nbsp;Bao-Jiang Ren ,&nbsp;Xin-Wen Zhou ,&nbsp;Guo-Hua Zhang ,&nbsp;Kuo-Chih Chou","doi":"10.1016/j.powtec.2025.121705","DOIUrl":"10.1016/j.powtec.2025.121705","url":null,"abstract":"<div><div>Tungsten and its alloys occupy a critical position in modern defense, nuclear energy, vacuum electronics, and lighting applications due to their unique and irreplaceable properties. However, the intrinsic brittleness, thermal shock brittleness, and recrystallization brittleness of tungsten significantly limit its application and development. To address the high brittleness and poor strength-toughness of tungsten, the present work aimed to first prepare La₂O₃ dispersion-strengthened composite powders by spray drying‑hydrogen reduction process. Subsequently, highly dense ultrafine-grained dispersion-strengthened W alloys were fabricated via spark plasma sintering (SPS). It was indicated that La₂O₃ exhibited a significant refining effect on the powder; however, excessive La₂O₃ addition led to aggregation, promoting the chemical vapor transport (CVT) mechanism and ultimately causing powder coarsening. During the sintering process, the uneven distribution and aggregation of secondary phase particles diminished their grain refinement capability. The resulting nanostructured W-0.5La₂O₃ (wt%) composite powder exhibited a grain size of 109 nm, while the W-0.5La₂O₃ alloy possessed the highest Vickers hardness of 647.9 HV_0.2. Furthermore, the reduction and densification mechanisms of composite powder were investigated in detail.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"469 ","pages":"Article 121705"},"PeriodicalIF":4.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145227770","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}

{"title":"Study on wheel-rail adhesion restoration effect by sanding using novel adhesion-enhancement particles","authors":"Chao Wang ,&nbsp;Wenjian Wang ,&nbsp;Ziheng Yue ,&nbsp;Haohao Ding ,&nbsp;Shuyue Zhang ,&nbsp;Jun Guo","doi":"10.1016/j.powtec.2025.121703","DOIUrl":"10.1016/j.powtec.2025.121703","url":null,"abstract":"<div><div>Hard particles are widely used for wheel-rail adhesion enhancement under low adhesion conditions, but it would intensify the wheel-rail damage. In order to achieve the same or better adhesion restoration effect as commonly used particles (e.g., Silica sand, Alumina, etc.) while reducing the wheel-rail damage caused by particles, a novel adhesion-enhancement particle was prepared in this study. The crushing stress of the novel particle with different preparation parameters were studied on a uniaxial compression apparatus. The wheel-rail adhesion restoration effect caused by the novel particles were studied under oil condition by a twin-disc wheel-rail testing machine. Results indicated that when the particle crushing stress increased from 20 MPa to 68 MPa, the adhesion coefficient increased. Then the adhesion coefficient kept stable after particle crushing stress exceeded 68 MPa. The novel adhesion-enhancement particle showed a better performance on wheel-rail adhesion improvement compared to sand and alumina. Considering the adhesion coefficient, wear and damage of wheel-rail, the novel unsintered particles with crushing stress of 20 MPa could be used as a substitute for sand on adhesion coefficient improvement under conditions with low requirements for adhesion enhancement, and the sintered novel adhesion-enhancement particles with crushing stress of 68 MPa could be optimal particles for wheel-rail adhesion restoration under high requirements for adhesion enhancement condition.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"469 ","pages":"Article 121703"},"PeriodicalIF":4.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264701","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}

{"title":"Optimization design of the system for rock fragmentation by high-voltage pulsed discharge","authors":"Hongbin Liao ,&nbsp;Yi Liu ,&nbsp;Yong Zhao ,&nbsp;Bohan Zhang ,&nbsp;Jin Cheng ,&nbsp;Fuchang Lin","doi":"10.1016/j.powtec.2025.121708","DOIUrl":"10.1016/j.powtec.2025.121708","url":null,"abstract":"<div><div>Aiming to address the lack of a quantitative analysis in the design of the system for rock fragmentation by high-voltage pulsed discharge (RHPD), an optimization design method for the RHPD system based on medium breakdown characteristics and stress impulse constraints is proposed, and a multi-physical parameter coupling mathematical model based on numerical calculation and circuit simulation is constructed. Considering the drilling condition with a 3 1/2 in. wellbore diameter, the optimal energy parameter of the RHPD system with an 88.9 mm claw-shaped discharge electrode is obtained based on the optimization design model. The optimal energy parameter of the system and the corresponding equivalent capacitance, equivalent charging voltage of the system are 58.75 J, 2.966 nF, and 199.03 kV, respectively. Using these optimal parameters, a RHPD system with a coaxial Marx generator as the topological structure is developed. The rock fragmentation performance of the system is tested in a transformer oil-granite medium. After 180 min, a drilling effect is observed on the granite surface, with a hole diameter of 92.66 mm and a depth of 35.70 mm. The energy consumption per unit volume for fragmentation of the developed system is approximately 967 J/cm³, and the rate of penetration at a 10 Hz pulse discharge frequency is approximately 0.3 m/h. This research provides theoretical guidance for the parameter optimization and structural design of the RHPD system.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"469 ","pages":"Article 121708"},"PeriodicalIF":4.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264698","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}

{"title":"A dynamic restitution coefficient model incorporating friction, impact velocity, and temperature effects: Validation in a bubbling fluidized bed","authors":"Xinyao Guo ,&nbsp;Chunlei Wang ,&nbsp;Xiaohui Li ,&nbsp;Guodong Liu","doi":"10.1016/j.powtec.2025.121722","DOIUrl":"10.1016/j.powtec.2025.121722","url":null,"abstract":"<div><div>We present a physics-based, dynamic coefficient of restitution (CoR) model for gas–solid flows that explicitly accounts for particle friction, impact velocity, and material temperature-effects neglected in conventional constant-CoR models. In dilute regions, CoR is expressed as a function of impact velocity and temperature; in dense regions, an effective CoR captures collective damping. A smooth transition between regimes is governed by the inertial number, ensuring physical consistency across flow regimes. Integrated into the two-fluid model based on the kinetic theory of granular flow (TFM-KTGF), the model is validated against bubbling fluidized bed experiments and Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) simulations. Results demonstrate marked improvements in predicting solid mass flux, bubble dynamics, and energy dissipation, establishing the model as a robust tool for accurate simulation of complex gas-solid flows.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"469 ","pages":"Article 121722"},"PeriodicalIF":4.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264699","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}

{"title":"Compressive strength, flexural strength, and slump of recycled aggregate fibre-reinforced fly ash concrete using explainable extreme gradient boosting machine learning model with prediction tool","authors":"Abdelrahman Abushanab,&nbsp;Vanissorn Vimonsatit","doi":"10.1016/j.powtec.2025.121710","DOIUrl":"10.1016/j.powtec.2025.121710","url":null,"abstract":"<div><div>This study develops machine learning predictive models to evaluate the compressive strength (<em>f'</em>_<em>c</em>), flexural tensile strength (<em>f</em>_<em>r</em>), and slump of recycled aggregate fibre-reinforced fly ash concrete (RAFRC-FA). The models were developed using a database compiling 1028, 531, and 430 records for <em>f'</em>_<em>c</em>, <em>f</em>_<em>r</em>, and slump, respectively, with 21 input parameters related to concrete constituents, fly ash, fibres, and concrete testing age (for <em>f'</em>_<em>c</em> and <em>f</em>_<em>r</em>). A total of 8 machine learning models representing single and ensemble algorithms were adopted in this study. The results revealed that the extreme gradient boosting (XGB) model outperformed all models, with mean absolute error and coefficient of determination of 2.10 MPa and 95.11% for <em>f'</em>_<em>c</em>, 0.26 MPa and 92.16% for <em>f</em>_<em>r</em>, and 15.54 mm and 85.98% for slump, respectively. Moreover, the XGB model exhibited the lowest standard deviation (0.024 and 0.042) and coefficient of variance (2.36% and 4.20%) of predicted-to-actual ratios compared to conventional analytical models for <em>f'</em>_<em>c</em> and <em>f</em>_<em>r</em>, respectively. In addition, the SHapley Additive exPlanation (SHAP) tool illustrated that concrete ingredients were the most influential factors affecting the compressive and flexural strength of RAFRC-FA, whereas the aggregate properties exhibited the highest impact on the slump of RAFRC-FA. Furthermore, a web-based application was developed and verified using unseen data for the prediction of the mechanical properties of RAFRC-FA. The experimental-to-predicted ratios of the predictions of the <em>f'</em>_<em>c</em>, <em>f</em>_<em>r</em>, and slump by the web-based application were in the range of 1.00 to 1.13, 0.99 to 1.06, and 1.00 to 1.13, respectively.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"469 ","pages":"Article 121710"},"PeriodicalIF":4.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264707","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}

{"title":"Investigation of temporary plugging agents transport and plugging behavior in fractures using CFD-DEM coupling method","authors":"Wenyu Wang ,&nbsp;Tiankui Guo ,&nbsp;Ming Chen ,&nbsp;Yongzan Liu ,&nbsp;Mingkun Lv ,&nbsp;Tong Hao ,&nbsp;Zhanqing Qu ,&nbsp;Juntao Liu ,&nbsp;Rui Xu","doi":"10.1016/j.powtec.2025.121717","DOIUrl":"10.1016/j.powtec.2025.121717","url":null,"abstract":"<div><div>Intra-fracture temporary plugging fracturing is an effective technique for the creation of multi-level branched fractures. The transport and plugging performance of temporary plugging agents (TPAs) within fractures directly determines the efficiency of the fracturing operation. However, there are few studies addressing the growth mechanisms of the plugging layer, and the influence of key TPA physical properties (such as particle shape and friction coefficient) on plugging efficiency remains poorly understood. This lack of understanding hinders the theoretical foundation necessary for the optimized design of intra-fracture temporary plugging strategies. In this study, a high-fidelity numerical model based on a coupled CFD–DEM approach, which accurately accounts for particle–particle contact and collision behaviors, was developed to simulate the transport and plugging process of TPAs within fractures. A comprehensive investigation was conducted to understand the plugging behavior under varying operational parameters. The results indicate that the growth of the plugging layer follows four distinct stages, different operational parameters primarily influence the growth characteristics by altering the particle sedimentation rates at the front and rear of the accumulation zone. An increase in friction coefficient enhances bridging capability and results in a 74.07 % reduction in plugging layer length. Small-diameter TPAs (1.2 mm) exhibit poor plugging performance due to their low bridging probability, which can be improved through synergistic injection of mixed particle sizes. Irregular-shaped particles form interlocking structures via multi-point contacts, enhancing the mechanical stability of the plugging layer. An optimal TPA density range of 1120–1300 kg·m⁻³ is recommended.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"469 ","pages":"Article 121717"},"PeriodicalIF":4.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264205","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}

{"title":"Theoretical modeling for liquid-assisted in-situ CO2 rapid laser reactive sintering of protonic ceramic materials","authors":"Keqiang Fan ,&nbsp;Mengyang Yu ,&nbsp;Jingjun Ren ,&nbsp;Jingwei Ge ,&nbsp;Jincheng Lei ,&nbsp;Shenglong Mu","doi":"10.1016/j.powtec.2025.121725","DOIUrl":"10.1016/j.powtec.2025.121725","url":null,"abstract":"<div><div>In proton-conducting solid-state electrochemical devices (such as protonic ceramic fuel cells), the densification of electrolytes and the porous structure of electrodes are crucial for performance and stability, with the sintering process playing a decisive role. Conventional sintering requires prolonged high-temperature treatment, leading to elemental evaporation, high energy consumption, long processing time, and increased costs. To address these issues, the liquid-phase-assisted in-situ CO₂ rapid laser reactive sintering (RLRS) technique demonstrates significant advantages by utilizing high-energy laser for localized rapid heating. This study established a theoretical model of RLRS to investigate the effects of different laser parameters on the porous structure of the anode and the densification of the deposited BaCe_0.7Zr_0.1Yb_0.1Yb_0.1O_₃-δ (BCZYYb) electrolyte, and determined the optimal process. Experiments have confirmed that under this process, the electrolytes are dense and anodic porous, they are tightly bonded, do not delaminate or crack, and have excellent electrochemical properties.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"469 ","pages":"Article 121725"},"PeriodicalIF":4.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264612","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}

{"title":"Effect of liquid surface tension on the detachment behavior of an air bubble and a glass bead","authors":"Mianyan Yang,&nbsp;Zhongqi Wei,&nbsp;Zhijun Zhang","doi":"10.1016/j.powtec.2025.121697","DOIUrl":"10.1016/j.powtec.2025.121697","url":null,"abstract":"<div><div>The effect of liquid surface tension on the detachment behavior of bubbles and different hydrophobic glass beads was investigated. By measuring the receding contact angle, induction time and detachment force, the mechanism of liquid surface tension on the detachment of bubbles and different hydrophobic glass beads was revealed. The results showed that when liquid surface tension was decreased from 72.86 ± 0.05 mN/m to 71.76 ± 0.04 mN/m, there were slight changes in receding contact angle, induction time and critical detachment force of different hydrophobic glass beads. This indicates that liquid diffusion and wetting on the glass bead surface were limited, and had a minimal effect on detachment behavior in a certain range of liquid surface tension. However, when the liquid surface tensions were 58.16 ± 0.12 mN/m and 41.74 ± 0.22 mN/m, the liquid diffusion and wetting on the different hydrophobic glass bead surfaces were enhanced. The receding contact angle and critical detachment force between bubbles and glass beads were decreased. It indicates that the extension of three-phase contact line (TPCL) between bubbles and different hydrophobic glass beads was hindered, thereby decreasing the stability of the aggregates. This research provides guidance on selecting optimal surface tension for separating different hydrophobic particles, therefore improving flotation performance.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"468 ","pages":"Article 121697"},"PeriodicalIF":4.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217281","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}