Pub Date : 2025-02-11DOI: 10.1016/j.powtec.2025.120753
Zhijun Xu , Huijie Guo , Yong Cheng , Yang Han , Huawei Tao
It is challenging to develop a widely accepted model for predicting the dynamic normal stress (DNS) on silo wall. A lightweight and explainable model was proposed to predict the dynamic normal stress (DNS) on silo wall, assisted by knowledge distillation (KD). Feature distribution and correlation analyses were performed to establish a novel DNS database by eliminating redundant features. Various machine learning models were compared for accuracy and efficiency. Results indicate that the optimized model shows significant performance improvement. Adding residual modules and increasing the number of network layers effectively enhance the performance of the ResGRU model. Feature fusion and derivative modules drives derivation distillation (DD) model, reducing the number of parameters and storage space. Finally, SHAP method was used to help the proposed model to explain the importance ranking of the features, and it is recommended first to consider granular material type, aspect ratio, and hopper angle when designing silo structures.
{"title":"A lightweight and explainable model to predict the dynamic normal stress on silo wall assisted with knowledge distillation","authors":"Zhijun Xu , Huijie Guo , Yong Cheng , Yang Han , Huawei Tao","doi":"10.1016/j.powtec.2025.120753","DOIUrl":"10.1016/j.powtec.2025.120753","url":null,"abstract":"<div><div>It is challenging to develop a widely accepted model for predicting the dynamic normal stress (DNS) on silo wall. A lightweight and explainable model was proposed to predict the dynamic normal stress (DNS) on silo wall, assisted by knowledge distillation (KD). Feature distribution and correlation analyses were performed to establish a novel DNS database by eliminating redundant features. Various machine learning models were compared for accuracy and efficiency. Results indicate that the optimized model shows significant performance improvement. Adding residual modules and increasing the number of network layers effectively enhance the performance of the ResGRU model. Feature fusion and derivative modules drives derivation distillation (DD) model, reducing the number of parameters and storage space. Finally, SHAP method was used to help the proposed model to explain the importance ranking of the features, and it is recommended first to consider granular material type, aspect ratio, and hopper angle when designing silo structures.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"455 ","pages":"Article 120753"},"PeriodicalIF":4.5,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394693","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 : 2025-02-11DOI: 10.1016/j.powtec.2025.120770
Stefan Vogel , Ali Akbar Sarbanha , Seyed Mohammed Taghavi , Markus Schubert , Faïçal Larachi
This study investigates precision mist injection into a cuboidal pseudo-2D fluidized bed on a robotic sea wave simulator to stabilize bubbling and homogenize hydrodynamics under 9° inclination and 0.1 Hz rolling motion. Digital image analysis and particle image velocimetry are used to evaluate the effects of mist injection on defluidization, void fraction, particle motion, and fluidization regime changes. Liquid injection effectively reduces bubble and slug sizes and controls particle velocities without causing defluidization/agglomeration. Symmetric injection is ineffective in inclined beds and does not significantly reduce slug size in rolling beds, but does reduce bubble size. Asymmetric injection consistently performs better, especially in rolling conditions, by reducing bubble size and velocity and reducing slugging. Double point injection proves to be the most reliable and significantly reduces bed maldistribution in rolling configurations. These results suggest potential offshore applications, where mist-induced surface changes reduce sensitivity to sea-like motion.
{"title":"Precision mist injection strategy for enhanced hydrodynamic stability in oscillating bubbling fluidized beds","authors":"Stefan Vogel , Ali Akbar Sarbanha , Seyed Mohammed Taghavi , Markus Schubert , Faïçal Larachi","doi":"10.1016/j.powtec.2025.120770","DOIUrl":"10.1016/j.powtec.2025.120770","url":null,"abstract":"<div><div>This study investigates precision mist injection into a cuboidal pseudo-2D fluidized bed on a robotic sea wave simulator to stabilize bubbling and homogenize hydrodynamics under 9° inclination and 0.1 Hz rolling motion. Digital image analysis and particle image velocimetry are used to evaluate the effects of mist injection on defluidization, void fraction, particle motion, and fluidization regime changes. Liquid injection effectively reduces bubble and slug sizes and controls particle velocities without causing defluidization/agglomeration. Symmetric injection is ineffective in inclined beds and does not significantly reduce slug size in rolling beds, but does reduce bubble size. Asymmetric injection consistently performs better, especially in rolling conditions, by reducing bubble size and velocity and reducing slugging. Double point injection proves to be the most reliable and significantly reduces bed maldistribution in rolling configurations. These results suggest potential offshore applications, where mist-induced surface changes reduce sensitivity to sea-like motion.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"455 ","pages":"Article 120770"},"PeriodicalIF":4.5,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-11DOI: 10.1016/j.powtec.2025.120776
Huaqing Ma , Chang Liu , Wenrui Wang , Zihan Liu , Lianyong Zhou , Zongqing Zhou , Kaiwei Chu , Yongzhi Zhao
The transport of the particulate materials in a flexible tube is commonly encountered in practical applications, in which the flexible tube is easily susceptible to deformation and movement. However, there are relatively few published fundamental studies for investigating the particle transport process in a flexible tube, particularly at the particle level. As a consequence, the particle-scale DEM (Discrete Element Method) is coupled with FEM (Finite Element Method) in this work to simulate the particle flow in a flexible tube, in which the particle phase and the flexible tube are solved by DEM and FEM, respectively. The experiment of the flow of the copper spheres in a flexible silicone tube is then conducted to validate the accuracy of the developed DEM-FEM model, where the experimental apparatus mainly consists of a flexible tube, a hopper used to store particles prior to the commencement of the experiment, and a container to collect the particles that discharge from the tube. Subsequently, the particle flows in a flexible tube are simulated by DEM-FEM, and the relatively comprehensive investigation for exploring the impacts of physical properties of the tube (including Young's modulus, density and damping ratio) on the behaviors of the particles and the tube (e.g., particle velocity, shear impact energy and vibration displacement behavior of the tube) is performed. According to the simulation results, the Young's modulus and the tube density can significantly affect both the particle behaviors and the tube deformation and movement behaviors, whereas the particle behaviors are slightly affected by the damping ratio.
{"title":"DEM-FEM investigation of the particle transport process in a flexible tube","authors":"Huaqing Ma , Chang Liu , Wenrui Wang , Zihan Liu , Lianyong Zhou , Zongqing Zhou , Kaiwei Chu , Yongzhi Zhao","doi":"10.1016/j.powtec.2025.120776","DOIUrl":"10.1016/j.powtec.2025.120776","url":null,"abstract":"<div><div>The transport of the particulate materials in a flexible tube is commonly encountered in practical applications, in which the flexible tube is easily susceptible to deformation and movement. However, there are relatively few published fundamental studies for investigating the particle transport process in a flexible tube, particularly at the particle level. As a consequence, the particle-scale DEM (Discrete Element Method) is coupled with FEM (Finite Element Method) in this work to simulate the particle flow in a flexible tube, in which the particle phase and the flexible tube are solved by DEM and FEM, respectively. The experiment of the flow of the copper spheres in a flexible silicone tube is then conducted to validate the accuracy of the developed DEM-FEM model, where the experimental apparatus mainly consists of a flexible tube, a hopper used to store particles prior to the commencement of the experiment, and a container to collect the particles that discharge from the tube. Subsequently, the particle flows in a flexible tube are simulated by DEM-FEM, and the relatively comprehensive investigation for exploring the impacts of physical properties of the tube (including Young's modulus, density and damping ratio) on the behaviors of the particles and the tube (<em>e.g.</em>, particle velocity, shear impact energy and vibration displacement behavior of the tube) is performed. According to the simulation results, the Young's modulus and the tube density can significantly affect both the particle behaviors and the tube deformation and movement behaviors, whereas the particle behaviors are slightly affected by the damping ratio.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"455 ","pages":"Article 120776"},"PeriodicalIF":4.5,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394692","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 : 2025-02-10DOI: 10.1016/j.powtec.2025.120771
Brady Wright, Kevin Galvin, Mahshid Firouzi
Gangue particles, which are typically hydrophilic, impede the efficient recovery of valuable hydrophobic particles in flotation cells, and in turn lower the grade of the final concentrate. The system hydrodynamics, including the gas and liquid fluxes, and bubble segregation, plays a key role in the efficient separation of the valuable and gangue mineral particles. In conventional flotation cells, an increase in the gas flux leads to increased entrainment of the gangue minerals, due to an increase in water recovery. This new work investigates the effects of the gas flux and liquid fluxes on gangue entrainment in a Reflux Flotation Cell (RFC), a novel system that incorporates parallel inclined channels to prevent bubble losses to tailings.
The study focused exclusively on fine hydrophilic silica as the model gangue mineral in the feed, completely excluding hydrophobic particles. Rigorous, continuous, steady state experiments produced an accurate measure of the particle transport into the concentrate. It was concluded that the wash water addition removed the bulk entrainment. Hence, the observed entrainment was primarily due to bubble surface entrainment. Interestingly, the silica entrainment decreased with increasing the gas flux and wash water flux. The system hydrodynamics was quantified through measurement of the gas hold-up and the bubble size distribution. Drift flux theory was applied to these accurate datasets, confirming the significant role of enhanced segregation of the bubbles due to the presence of the inclined channels, an effect known as the Boycott Effect.
{"title":"Effect of gas flux on gangue recovery in a reflux flotation cell - a modelling and experimental study","authors":"Brady Wright, Kevin Galvin, Mahshid Firouzi","doi":"10.1016/j.powtec.2025.120771","DOIUrl":"10.1016/j.powtec.2025.120771","url":null,"abstract":"<div><div>Gangue particles, which are typically hydrophilic, impede the efficient recovery of valuable hydrophobic particles in flotation cells, and in turn lower the grade of the final concentrate. The system hydrodynamics, including the gas and liquid fluxes, and bubble segregation, plays a key role in the efficient separation of the valuable and gangue mineral particles. In conventional flotation cells, an increase in the gas flux leads to increased entrainment of the gangue minerals, due to an increase in water recovery. This new work investigates the effects of the gas flux and liquid fluxes on gangue entrainment in a Reflux Flotation Cell (RFC), a novel system that incorporates parallel inclined channels to prevent bubble losses to tailings.</div><div>The study focused exclusively on fine hydrophilic silica as the model gangue mineral in the feed, completely excluding hydrophobic particles. Rigorous, continuous, steady state experiments produced an accurate measure of the particle transport into the concentrate. It was concluded that the wash water addition removed the bulk entrainment. Hence, the observed entrainment was primarily due to bubble surface entrainment. Interestingly, the silica entrainment decreased with increasing the gas flux and wash water flux. The system hydrodynamics was quantified through measurement of the gas hold-up and the bubble size distribution. Drift flux theory was applied to these accurate datasets, confirming the significant role of enhanced segregation of the bubbles due to the presence of the inclined channels, an effect known as the Boycott Effect.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"455 ","pages":"Article 120771"},"PeriodicalIF":4.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-10DOI: 10.1016/j.powtec.2025.120774
Xiao-Hua Tan , Xiao-Jun Zhou , Peng Xu , Yao Zhu , Dai-Jin Zhuang
The coupling behavior of fluid and solid strain is difficult to describe, making it challenging to characterize and accurately predict permeability changes of porous media in complex environments. In order to improve universality and reliability of the model, the comprehensive effects of factors such as solid particle detachment, fluid solid coupling, multiphase flow, and stress sensitivity on the permeability of porous media are fully considered, establishing a fluid structure coupling stress sensitive permeability model based on material mechanics and fractal theory. The model is validated through stress-sensitivity experiments and particle steadiness tests, as well as previous experimental data. Key findings include: (1) The increase in stress, porosity, and water saturation results in an increase in the applied pressure required for a sudden change in normalized permeability, while the rate of decrease slows down; (2) The increase in fractal dimension of tortuosity will increase applied pressure for sudden changes in permeability; (3) The larger the fractal dimension of movable solid particles, the higher the tortuosity of solid particles, the smaller the fractal dimension of solid particles, and the faster the normalized permeability reduction rate. This model provides theoretical guidance for accurately predicting the flow behavior and development of stress sensitive reservoirs.
{"title":"A fractal geometry-based model for stress-sensitive permeability in porous media with fluid-solid coupling","authors":"Xiao-Hua Tan , Xiao-Jun Zhou , Peng Xu , Yao Zhu , Dai-Jin Zhuang","doi":"10.1016/j.powtec.2025.120774","DOIUrl":"10.1016/j.powtec.2025.120774","url":null,"abstract":"<div><div>The coupling behavior of fluid and solid strain is difficult to describe, making it challenging to characterize and accurately predict permeability changes of porous media in complex environments. In order to improve universality and reliability of the model, the comprehensive effects of factors such as solid particle detachment, fluid solid coupling, multiphase flow, and stress sensitivity on the permeability of porous media are fully considered, establishing a fluid structure coupling stress sensitive permeability model based on material mechanics and fractal theory. The model is validated through stress-sensitivity experiments and particle steadiness tests, as well as previous experimental data. Key findings include: (1) The increase in stress, porosity, and water saturation results in an increase in the applied pressure required for a sudden change in normalized permeability, while the rate of decrease slows down; (2) The increase in fractal dimension of tortuosity will increase applied pressure for sudden changes in permeability; (3) The larger the fractal dimension of movable solid particles, the higher the tortuosity of solid particles, the smaller the fractal dimension of solid particles, and the faster the normalized permeability reduction rate. This model provides theoretical guidance for accurately predicting the flow behavior and development of stress sensitive reservoirs.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"455 ","pages":"Article 120774"},"PeriodicalIF":4.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422215","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 : 2025-02-10DOI: 10.1016/j.powtec.2025.120768
Jingru Hu, Zhongwei Huang, Sitong Wu, Jingbin Li, Dong Yang, Hou Zhong, Kang Cheng, Gensheng Li
Ice-air jet technology has emerged as a promising alternative to conventional abrasive methods for surface treatment. This study investigates the aerodynamic and thermodynamic characteristics of a Laval nozzle-based pre-mixed ice-air jet system through numerical simulations. The results confirm that Laval nozzles effectively enhance ice particle acceleration and thermal stability, with ice particle peak velocity reaching 319 m/s, approximately 63.8 % of the peak gas velocity. The supersonic expansion facilitates efficient kinetic energy transfer while maintaining a stable low-temperature jet core, restricting ice particle temperature variation within 5 % to ensure particle integrity. A systematic evaluation of key structural parameters revealed that throat radius has the most significant influence, as it directly governs gas mass flow rate, jet core length, and ice particle acceleration. Larger throat radii extend the high-speed jet core and improve acceleration, while smaller radii promote greater radial dispersion of ice particles. In contrast, contraction and expansion angles primarily regulate flow stability and turbulence intensity, rather than directly enhancing acceleration. The recommended configuration for pre-mixed ice-air jet applications includes a throat radius of 4 mm, a contraction angle of 25°–35°, and an expansion angle of 1°–5°. Furthermore, a dimensionless impact distance of 35 × Rc was identified as the optimal operating range for balancing momentum transfer efficiency and thermal stability. These findings provide a basis for optimizing ice-air jet technology, contributing to the design of advanced pre-mixed high-speed jet nozzles for precision cleaning and surface treatment applications.
{"title":"Numerical investigation of flow field characteristics and key structural parameters impact in ice air jet based on Laval nozzle","authors":"Jingru Hu, Zhongwei Huang, Sitong Wu, Jingbin Li, Dong Yang, Hou Zhong, Kang Cheng, Gensheng Li","doi":"10.1016/j.powtec.2025.120768","DOIUrl":"10.1016/j.powtec.2025.120768","url":null,"abstract":"<div><div>Ice-air jet technology has emerged as a promising alternative to conventional abrasive methods for surface treatment. This study investigates the aerodynamic and thermodynamic characteristics of a Laval nozzle-based pre-mixed ice-air jet system through numerical simulations. The results confirm that Laval nozzles effectively enhance ice particle acceleration and thermal stability, with ice particle peak velocity reaching 319 m/s, approximately 63.8 % of the peak gas velocity. The supersonic expansion facilitates efficient kinetic energy transfer while maintaining a stable low-temperature jet core, restricting ice particle temperature variation within 5 % to ensure particle integrity. A systematic evaluation of key structural parameters revealed that throat radius has the most significant influence, as it directly governs gas mass flow rate, jet core length, and ice particle acceleration. Larger throat radii extend the high-speed jet core and improve acceleration, while smaller radii promote greater radial dispersion of ice particles. In contrast, contraction and expansion angles primarily regulate flow stability and turbulence intensity, rather than directly enhancing acceleration. The recommended configuration for pre-mixed ice-air jet applications includes a throat radius of 4 mm, a contraction angle of 25°–35°, and an expansion angle of 1°–5°. Furthermore, a dimensionless impact distance of 35 × <em>R</em><sub><em>c</em></sub> was identified as the optimal operating range for balancing momentum transfer efficiency and thermal stability. These findings provide a basis for optimizing ice-air jet technology, contributing to the design of advanced pre-mixed high-speed jet nozzles for precision cleaning and surface treatment applications.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"455 ","pages":"Article 120768"},"PeriodicalIF":4.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428142","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 : 2025-02-10DOI: 10.1016/j.powtec.2025.120773
Jiawei Zhou , Tang Gan , Xiangyu Yan , Yaojie Xu , Hongxiang Jiang
To clarify the relationship between flow regimes and acoustic signals in pneumatic conveying, the acoustic signal of pneumatic conveying process was non-intrusively collected. Frequency and energy characteristics of acoustic signals were analyzed by using the discrete wavelet transform (DWT) and the Hilbert-Huang transform (HHT) to reveal the flow regime transformation during pneumatic conveying. Results show that the effective acoustic signal of pneumatic conveying is mainly concentrated in the region of 0 to 37.5 Hz, and the amplitude of the acoustic signal is positively correlated with the discharge pressure. The flow regime changes from plug flow to dune flow and suspended flow with the increase in acoustic signal amplitude in. The summarized Hilbert spectrum energy of the acoustic signal during the steady conveying stage is mainly concentrated in the range of 0 to 20 Hz. The energy of the Intrinsic Mode Function (IMF) components shows a trend of first decreasing and then increasing with the discharge pressure, which corresponds to plug flow, dune flow, and suspended flow regimes, respectively.
{"title":"Relationship between pneumatic conveying flow regimes and acoustic signals based on DWT and HHT analysis","authors":"Jiawei Zhou , Tang Gan , Xiangyu Yan , Yaojie Xu , Hongxiang Jiang","doi":"10.1016/j.powtec.2025.120773","DOIUrl":"10.1016/j.powtec.2025.120773","url":null,"abstract":"<div><div>To clarify the relationship between flow regimes and acoustic signals in pneumatic conveying, the acoustic signal of pneumatic conveying process was non-intrusively collected. Frequency and energy characteristics of acoustic signals were analyzed by using the discrete wavelet transform (DWT) and the Hilbert-Huang transform (HHT) to reveal the flow regime transformation during pneumatic conveying. Results show that the effective acoustic signal of pneumatic conveying is mainly concentrated in the region of 0 to 37.5 Hz, and the amplitude of the acoustic signal is positively correlated with the discharge pressure. The flow regime changes from plug flow to dune flow and suspended flow with the increase in acoustic signal amplitude in. The summarized Hilbert spectrum energy of the acoustic signal during the steady conveying stage is mainly concentrated in the range of 0 to 20 Hz. The energy of the Intrinsic Mode Function (IMF) components shows a trend of first decreasing and then increasing with the discharge pressure, which corresponds to plug flow, dune flow, and suspended flow regimes, respectively.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"455 ","pages":"Article 120773"},"PeriodicalIF":4.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143386593","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 : 2025-02-10DOI: 10.1016/j.powtec.2025.120767
Huaiyuan Qian , Rui Tan , Bei Wu , Fangping Xie , Dawei Liu , Tianci Huang , Qingmiao Xiang
The anchor mixer and the vertical helical ribbon mixer each offer distinct advantages in terms of mixing efficiency and uniformity. Building on the design of the Anchor Mixer (AM), two new models were developed to obtain a fusion of tangential and axial flow: the Anchor-Inner Helical Ribbon Combined Mixer (AIHRM) and the Anchor-Outer Helical Ribbon Combined Mixer (AOHRM). Numerical simulations and bench tests were conducted to compare the mixing processes and effects of these different mixers. The contact-based and variance-based mixing indices were employed to evaluate the mixing performance. The numerical simulation results demonstrated that the mixing index q reached 0.2 at 10 s within the AOHRM, whereas the AM only achieved a q value of approximately 0.15 at the same interval. The bench test results showed that the coefficient of variation (RSD) for AM decreased from 0.87 to 0.56 with the rotational speed increased, while for AOHRM, the RSD value decreased from 0.66 to 0.37 over the same range of speeds. Meanwhile, the RSD value for AM decreased from 0.96 to 0.40, and for AOHRM, it fell from 0.72 to 0.31 over a different period of mixing time. The combined anchor-helical ribbon mixer significantly obtains a better mixing homogeneity and promotes axial flow. In comparison to the AIHRM, the AOHRM lifts and disperses particles over the particle bed, thereby facilitating more extensive particle position exchange. Additionally, the AOHRM exhibits a wider range of disturbances, which aids in eliminating dead zones at the bottom and sides of the mixing vessel.
{"title":"Enhancing mixing efficiency and homogeneity by combining anchor and helical ribbon agitators","authors":"Huaiyuan Qian , Rui Tan , Bei Wu , Fangping Xie , Dawei Liu , Tianci Huang , Qingmiao Xiang","doi":"10.1016/j.powtec.2025.120767","DOIUrl":"10.1016/j.powtec.2025.120767","url":null,"abstract":"<div><div>The anchor mixer and the vertical helical ribbon mixer each offer distinct advantages in terms of mixing efficiency and uniformity. Building on the design of the Anchor Mixer (AM), two new models were developed to obtain a fusion of tangential and axial flow: the Anchor-Inner Helical Ribbon Combined Mixer (AIHRM) and the Anchor-Outer Helical Ribbon Combined Mixer (AOHRM). Numerical simulations and bench tests were conducted to compare the mixing processes and effects of these different mixers. The contact-based and variance-based mixing indices were employed to evaluate the mixing performance. The numerical simulation results demonstrated that the mixing index <em>q</em> reached 0.2 at 10 s within the AOHRM, whereas the AM only achieved a <em>q</em> value of approximately 0.15 at the same interval. The bench test results showed that the coefficient of variation (<em>RSD</em>) for AM decreased from 0.87 to 0.56 with the rotational speed increased, while for AOHRM, the <em>RSD</em> value decreased from 0.66 to 0.37 over the same range of speeds. Meanwhile, the <em>RSD</em> value for AM decreased from 0.96 to 0.40, and for AOHRM, it fell from 0.72 to 0.31 over a different period of mixing time. The combined anchor-helical ribbon mixer significantly obtains a better mixing homogeneity and promotes axial flow. In comparison to the AIHRM, the AOHRM lifts and disperses particles over the particle bed, thereby facilitating more extensive particle position exchange. Additionally, the AOHRM exhibits a wider range of disturbances, which aids in eliminating dead zones at the bottom and sides of the mixing vessel.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"455 ","pages":"Article 120767"},"PeriodicalIF":4.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394689","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 : 2025-02-10DOI: 10.1016/j.powtec.2025.120769
Jianing Li , Nian-Zhong Chen
A Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) based model is developed to simulate the coarse particle-liquid two-phase flow in a deep-sea mining vertical pipe. In this model, the traditional Eulerian–Lagrangian method in a Discrete Particle Method FOAM (DPMFoam) solver is modified by introducing a Virtual Mass Distribution Function (VMDF) to solve the governing equations for coarse particles and fluid phases, in which a collision model is also introduced to take into account the collision effects of particles with walls, and particles with particles. The numerical accuracy of the developed CFD-DEM model is validated by the comparison with the experimental results. The flow field patterns of the coarse particle-liquid two-phase flow are then analyzed and a sensitivity analysis is conducted to investigate the effects of variation of transport parameters on the local concentration of coarse particles and the velocity distribution characteristics of coarse particles and fluid. The results show that the local concentration of particles is increased with the increase of the diameter and volume concentration of particle, and it is decreased with the increase of transport velocity. For high particle volume concentration, large particle diameter or low transport velocity, the “retention effect” is easily triggered, leading to blockage within the vertical pipe.
{"title":"Numerical simulation of coarse particle-liquid two-phase flow in deep-sea mining vertical pipes","authors":"Jianing Li , Nian-Zhong Chen","doi":"10.1016/j.powtec.2025.120769","DOIUrl":"10.1016/j.powtec.2025.120769","url":null,"abstract":"<div><div>A Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) based model is developed to simulate the coarse particle-liquid two-phase flow in a deep-sea mining vertical pipe. In this model, the traditional Eulerian–Lagrangian method in a Discrete Particle Method FOAM (DPMFoam) solver is modified by introducing a Virtual Mass Distribution Function (VMDF) to solve the governing equations for coarse particles and fluid phases, in which a collision model is also introduced to take into account the collision effects of particles with walls, and particles with particles. The numerical accuracy of the developed CFD-DEM model is validated by the comparison with the experimental results. The flow field patterns of the coarse particle-liquid two-phase flow are then analyzed and a sensitivity analysis is conducted to investigate the effects of variation of transport parameters on the local concentration of coarse particles and the velocity distribution characteristics of coarse particles and fluid. The results show that the local concentration of particles is increased with the increase of the diameter and volume concentration of particle, and it is decreased with the increase of transport velocity. For high particle volume concentration, large particle diameter or low transport velocity, the “retention effect” is easily triggered, leading to blockage within the vertical pipe.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"455 ","pages":"Article 120769"},"PeriodicalIF":4.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422297","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 : 2025-02-09DOI: 10.1016/j.powtec.2025.120750
Qianlong Li , Bingwen Wang , Chenyi Liu , Mingchao Kang , Lei Yang
To combine the coarse aggregates into cemented paste backfill provides a feasible method to improve workability performance. In this study, two types of cold-bonded tailings lightweight aggregates (CBTLWAs) with the discrete (uniform particle size d = 2–8 mm) and continuous (Talbot coefficient n = 0.2–0.8) gradations at different dosages (15–40 wt%) were prepared and their influence on rheological as well as thixotropic behavior of cemented ultrafine tailings backfill (CUFTB) was explored accordingly. The obtained results illuminate that CUFTB incorporating CBTLWAs exhibits behavior of Bingham fluid irrespective of particle size gradations and dosages. With the increase of CBTLWAs dosage from 15 wt% to 40 wt%, both yield stress and plastic viscosity show a continuous decrease. For a fixed CBTLWAs dosage, the minimum values of yield stress and plastic viscosity are observed when d is 2 mm and n is 0.6. As a partial replacement for tailings, the addition of CBTLWAs reduces formation of floc structures and promote more release of free water, thus enhancing flowability of CUFTB. The thixotropic performance of CUFTB is weakened with addition of CBTLWAs. As the CBTLWAs dosage increases, the slump flow exhibits a linear increase trend. An exponential model is established to quantify the relationship between yield stress and slump flow values. The findings provide a guidance for the application of CBTLWAs in mine filling and contribute significant insights into sustainable mine tailings management.
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