Powder Technology最新文献_第8页

Dynamic spreading behavior of Mg-Zn-Zr powders in binder jetting additive manufacturing: Experiment and discrete element method Mg-Zn-Zr粉末在粘结剂喷射增材制造中的动态扩散行为：实验与离散元法

IF 4.6 2区工程技术 Q2 ENGINEERING, CHEMICAL

Powder Technology

Pub Date : 2025-12-29 DOI: 10.1016/j.powtec.2025.122103

Ze Zhao , Minghuan Yu , Junchao Li , Yunlong Tang , Zhongliang Lu

The quality of powder spreading is a crucial determinant in the densification of final components in binder jetting additive manufacturing (BJAM). Conventional assessments of powder flowability are limited by their static nature, which hinders the accurate representation of the dynamic spreading behavior of particles. Therefore, it is imperative to explore the key factors and mechanisms that influence powder bed performance. In this study, the flow behavior and evolution of force chains during Mg-Zn-Zr powder spreading were dynamically analyzed from both macro and micro perspectives via the integration of discrete element simulation and experimental validation. The combined effects of spreading speed, rotational speed, and layer thickness on the uniformity and stability of the powder bed were identified. It was suggested that a spreading speed of 50–70 mm/s, a rotational speed of 5–10 rad/s, and a layer thickness of 3–3.5D can effectively mitigate particle rheological failure and arching effects, thereby achieving a high-quality magnesium alloy powder bed. This research addresses the limitations of traditional macro-characterization by establishing a process optimization window for BJAM of magnesium alloys, focusing on the dynamic behavior of particles. It offers essential theoretical and process insights for the binder jetting manufacturing of high-performance, challenging-to-form materials.

粉末扩散质量是粘结剂喷射增材制造（BJAM）中最终部件致密化的关键决定因素。粉末流动性的传统评估受到其静态性质的限制，这阻碍了颗粒动态扩散行为的准确表示。因此，研究影响粉床性能的关键因素和机理势在必行。本研究采用离散元模拟和实验验证相结合的方法，从宏观和微观两个角度对Mg-Zn-Zr粉末扩散过程中的流动行为和力链演化进行了动态分析。确定了扩散速度、转速和层厚对粉床均匀性和稳定性的综合影响。结果表明，铺展速度为50 ~ 70 mm/s，转速为5 ~ 10 rad/s，层厚为3 ~ 3.5 d可有效减轻颗粒流变破坏和拱效应，从而获得高质量的镁合金粉床。本研究通过建立镁合金BJAM的工艺优化窗口，重点关注颗粒的动态行为，解决了传统宏观表征的局限性。它提供了重要的理论和工艺见解粘合剂喷射制造高性能，具有挑战性的成型材料。

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引用次数: 0

Influence of powder characteristics on flowability, slurry rheology, and photocuring performance 粉末特性对流动性、浆料流变性和光固化性能的影响

IF 4.6 2区工程技术 Q2 ENGINEERING, CHEMICAL

Powder Technology

Pub Date : 2025-12-29 DOI: 10.1016/j.powtec.2025.122096

Jung-Ting Tsai, Cheng-Han Wen

This study examines the impact of powder particle size, material density, and morphology on the flowability, rheological behavior, and curing properties of photocurable slurry in digital light processing (DLP) applications. The analysis was conducted using cordierite powders of varying particle sizes, titanium (Ti) and titanium alloy (Ti₆Al₄V) powders with identical particle sizes and morphologies, and alumina (Al₂O₃) powders with different morphologies. The avalanche angle measurements showed that smaller powders (D₅₀ = 3.3 μm) were prone to agglomeration, adversely affecting their flowability. Conversely, powders with higher material density or a more spherical morphology exhibited better powder flowability. The rheological properties show that as the particle size of cordierite decreased from D₅₀ = 53 μm to 3.3 μm, the slurry exhibited more pronounced shear-thinning behavior, with a decrease in viscosity from 263 Pa·s to 160 Pa·s, indicating improved flow characteristics. Furthermore, higher material density also led to a lower viscosity, as observed in a significant reduction from 32.3 Pa·s to 4.4 Pa·s. The influence of morphology was evident: the spherical alumina powder (7.6 Pa·s) exhibited lower viscosity than its irregularly shaped counterpart (12.9 Pa·s). Curing behavior shows that smaller particles (D50 = 3.3 μm) yielded a shallow cure depth of approximately 0.57 mm, whereas larger particles (D₅₀ = 53 μm) yielded a greater cure depth of 0.71 mm. Lastly, cordierite powder (D₅₀ = 14.7 μm) exhibited the highest exothermic peak (−46 mW) with the highest degree of conversion (74.24 %), demonstrating that a moderate reduction in particle size can enhance curing reaction efficiency.

本研究考察了粉末粒度、材料密度和形态对数字光处理（DLP）应用中光固化浆料的流动性、流变性能和固化性能的影响。采用不同粒度的堇青石粉末、相同粒度和形貌的钛（Ti）和钛合金（Ti6Al4V）粉末和不同形貌的氧化铝（Al2O3）粉末进行分析。雪崩角测量结果表明，粒径较小的粉末（D50 = 3.3 μm）易发生团聚，影响粉末的流动性。相反，材料密度越高或形貌越球形的粉末流动性越好。流变性能表明，当堇青石粒径从D50 = 53 μm减小到3.3 μm时，浆料剪切变稀行为更加明显，黏度从263 Pa·s减小到160 Pa·s，流动特性得到改善。此外，较高的材料密度也导致较低的粘度，从32.3 Pa·s显著降低到4.4 Pa·s。形貌的影响是明显的：球形氧化铝粉（7.6 Pa·s）的粘度低于不规则形状的氧化铝粉（12.9 Pa·s）。固化行为表明，小颗粒（D50 = 3.3 μm）的固化深度约为0.57 mm，而大颗粒（D50 = 53 μm）的固化深度为0.71 mm。最后，堇青石粉（D50 = 14.7 μm）的放热峰最高（- 46 mW），转化率最高（74.24%），表明适度减小粒径可以提高固化反应效率。

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引用次数: 0

Thickness-dependent phase transition thermodynamics of nanofilm in theory and experiment 纳米膜厚度相关相变热力学的理论与实验研究

IF 4.6 2区工程技术 Q2 ENGINEERING, CHEMICAL

Powder Technology

Pub Date : 2025-12-29 DOI: 10.1016/j.powtec.2025.122098

Huijuan Duan , Zuohui Cheng , Yongqiang Xue , Qun Wang , Xinru Song

The thickness of a nanofilm significantly influences its phase transition thermodynamics. In this paper, the effects of film thickness on the thermodynamic properties of phase transitions were investigated from both theoretical and experimental perspectives. First, a theoretical model for phase transitions in nanofilm was established, theoretical relationships between the key thermodynamic properties (including phase transition temperature, enthalpy and entropy) and film thickness were derived for the first time, and the influencing regularities and mechanisms of the film thickness on these thermodynamic properties were analyzed. Theoretical results show that the variation trends for phase transition temperature and enthalpy depend on the difference in interfacial tension before and after the phase transition, while the trend for entropy depends on the difference in the temperature coefficients of interfacial tension. When the film thickness is relatively large, these thermodynamic properties of phase transitions are linearly related to the reciprocal of the film thickness. Experimentally, lead titanate thin films with different thicknesses were taken as the research object, and corresponding phase transition temperature, enthalpy and entropy were measured by differential scanning calorimetry. The experimental results agree well with the theoretical prediction, validating the correctness of the theory. This study enhances the understanding of size effects on phase transition thermodynamics in thin films and provides a framework for designing and optimizing thin-film materials with tailored thermal properties.

纳米膜的厚度对其相变热力学有显著影响。本文从理论和实验两方面研究了薄膜厚度对相变热力学性质的影响。首先，建立了纳米膜相变的理论模型，首次推导了关键热力学性质（相变温度、焓和熵）与膜厚之间的理论关系，并分析了膜厚对这些热力学性质的影响规律和机理。理论结果表明，相变温度和焓的变化趋势取决于相变前后界面张力的差异，而熵的变化趋势取决于界面张力温度系数的差异。当薄膜厚度较大时，相变的热力学性质与薄膜厚度的倒数成线性关系。实验以不同厚度的钛酸铅薄膜为研究对象，采用差示扫描量热法测定了相应的相变温度、焓和熵。实验结果与理论预测吻合较好，验证了理论的正确性。该研究增强了对薄膜相变热力学中尺寸效应的理解，并为设计和优化具有定制热性能的薄膜材料提供了框架。

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引用次数: 0

Bottom-discharge blow tanks with non-mechanical valves for dense-phase conveying of rough, irregular particles: Operational effects and optimization 带非机械阀的粗、不规则颗粒密相输送底出吹罐：操作效果及优化

IF 4.6 2区工程技术 Q2 ENGINEERING, CHEMICAL

Powder Technology

Pub Date : 2025-12-29 DOI: 10.1016/j.powtec.2025.122064

Heitor Otacílio Nogueira Altino , Giovani Aud Lourenço , Carlos Henrique Ataíde , Claudio Roberto Duarte

Blow tank discharge and dense-phase pneumatic conveying of rough, irregular particles present significant challenges, including blockages, unstable discharge, and high pressure drops. When non-mechanical discharge valves are used, system performance becomes highly sensitive to material properties and operating conditions. This study quantifies and models the effects of pressurization airflow, fluidization airflow, discharge valve airflow, and loaded material mass on discharge flow rate, internal pressure, and pressure drop along the conveying line in bottom-discharge blow tanks with non-mechanical valves. A central composite design (CCD) was applied to an industrial-scale system to systematically assess how these variables influence system behavior, using drill cuttings as a representative material. The results enabled the quantification of both the individual and combined effects of airflow distribution through the blow tank and conveying line, along with material mass, on flow initiation, discharge rate stability, and pressure behavior throughout the system. Two optimal operating conditions were identified: one that maximized flow rate at the cost of higher pressure and greater blockage risk, and another that offered a more balanced trade-off between performance and operational stability. A state diagram, supported by pressure signal analysis, was used to characterize flow regimes, including transitions between dune and plug flow. These findings provide practical guidelines for improving the control and reliability of dense-phase pneumatic conveying systems handling irregular and cohesive materials.

吹罐卸料和密相气力输送粗颗粒、不规则颗粒面临重大挑战，包括堵塞、不稳定的卸料和高压降。当使用非机械排放阀时，系统性能对材料特性和操作条件变得高度敏感。本研究对带非机械阀的底排式吹罐加压气流、流化气流、排气阀气流、载料质量对输送线排出流量、内压和压降的影响进行了量化和建模。将中心复合设计（CCD）应用于工业规模的系统，以钻屑为代表材料，系统地评估这些变量如何影响系统行为。这些结果可以量化气流分布在吹罐和输送管线中的单独和综合影响，以及物料质量对整个系统的起流、排出率稳定性和压力行为的影响。确定了两种最佳作业条件：一种是以更高的压力和更大的堵塞风险为代价实现流量最大化，另一种在性能和作业稳定性之间提供了更平衡的权衡。在压力信号分析的支持下，使用状态图来表征流态，包括沙丘和塞流之间的转换。这些发现为改善处理不规则和粘性物料的密相气力输送系统的控制和可靠性提供了实用指南。

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引用次数: 0

Recognition of satellite particle based on SP-YOLO model 基于SP-YOLO模型的卫星粒子识别

IF 4.6 2区工程技术 Q2 ENGINEERING, CHEMICAL

Powder Technology

Pub Date : 2025-12-29 DOI: 10.1016/j.powtec.2025.122097

Lei Wang , Wei Liu , Liang Wang , Fan Yan , Yajing Wang , Fuyuan Qin

The presence of satellite particles degrades the quality and processing performance of metal powders, adversely affecting powder flowability and sphericity. Addressing the challenges of insufficient specialized research on satellite particle detection and their morphological complexity, this study improves upon the YOLOv8n model to construct the Satellite Particle-YOLO (SP-YOLO) model for identifying satellite particle types. First, a recursive dual pooling method combining max pooling and average pooling was employed to establish a multi-layer pyramid and integrate cross-stage partial connections, thereby constructing an Recursive Dual-pooling Spatial Pyramid Fusion (RDSPF) module to replace the original Spatial Pyramid Pooling Fast (SPPF) in the backbone network, enhancing multi-scale feature extraction capabilities. Second, the Dynamic Bottleneck Block (DBB) was integrated into dynamic convolution models to develop a Dynamic Branch Fusion (DBF) module, replacing part of the C2f structure in the neck network to strengthen detailed feature processing and improve target detection accuracy. Finally, the CIoU loss function was replaced with the Wise-EIoU loss function to enhance comprehensive geometric characterization of target bounding boxes. Experimental results demonstrate that the SP-YOLO model, incorporating RDSPF, DBF, and Wise-EIoU, achieved 85.5 % precision, 87.7 % recall, 91.8 % mAP50, and 90.5 % mAP50–95, representing improvements of 7.0 %, 1.1 %, 4.1 %, and 4.4 %, respectively. This method meets the requirements for precise and real-time recognition of satellite particles in practical production, providing technical reference for satellite particle identification and model deployment.

卫星颗粒的存在降低了金属粉末的质量和加工性能，对粉末的流动性和球形度产生不利影响。针对卫星粒子检测专业研究不足、形态复杂等问题，在YOLOv8n模型的基础上，构建了卫星粒子类型识别的卫星粒子- yolo （SP-YOLO）模型。首先，采用最大池化与平均池化相结合的递归双池化方法，建立多层金字塔，整合跨阶段部分连接，构建递归双池化空间金字塔融合（RDSPF）模块，取代原有的骨干网络空间金字塔池化快速（SPPF）模块，增强多尺度特征提取能力；其次，将动态瓶颈块（Dynamic Bottleneck Block， DBB）集成到动态卷积模型中，开发动态分支融合（Dynamic Branch Fusion， DBF）模块，取代颈部网络中的部分C2f结构，加强细节特征处理，提高目标检测精度；最后，将CIoU损失函数替换为Wise-EIoU损失函数，增强目标包围盒的综合几何表征。实验结果表明，结合RDSPF、DBF和Wise-EIoU的SP-YOLO模型的准确率为85.5%，召回率为87.7%，mAP50为91.8%，mAP50 - 95为90.5%，分别提高了7.0%、1.1%、4.1%和4.4%。该方法满足了实际生产中对卫星颗粒精确、实时识别的要求，为卫星颗粒识别和模型部署提供了技术参考。

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引用次数: 0

Exploration on bridging mechanism in steel fiber reinforced tailings composites through 3D visualization and X-ray CT techniques 利用三维可视化和x射线CT技术探讨钢纤维增强尾砂复合材料的桥接机理

IF 4.6 2区工程技术 Q2 ENGINEERING, CHEMICAL

Powder Technology

Pub Date : 2025-12-29 DOI: 10.1016/j.powtec.2025.122102

Yanxi Liu , Shuai Cao , Erol Yilmaz

Reinforcement behavior is of great importance for underground backfill systems, as all applied loads act upon it. Three kinds of steel fibers, namely, Hooked-End type (HE), Melt-Extracted type (ME) and Crimped type (C) with a dosage of 2.0 %, were used to prepare CTB specimens with 70 wt% solids and 1:4 binder/tail rate. Uniaxial compression experiments were adopted to assess macroscopic strength features of steel fiber-reinforced tungsten tails cemented backfill (SFCTB). X-ray computed tomography (CT) scanning technique was employed to inspect impacts of porosity, fracture features, and incorporation of diverse types of steel fibers on CTB's strength. Lab results indicate that incorporating steel fibers may augment structure of pores and effectively progress their morphologies. Adding HE and ME steel fibers can hinder fracture development and enhance the bearing capacity of SFCTB, but it leads to an increase in fracture volume by 0.84 % and 0.76 % respectively. In contrast, C steel fibers reduce the fracture volume by 0.47 %, significantly inhibiting fracture propagation and improving compressive strength. The incorporation of HE and C steel fibers decreases the 3D porosity (P_3D) by 0.054 % and 0.046 % respectively, while adding ME steel fibers rises P_3D by 0.372 %. Key factors such as porosity, crack distribution, and the 3D fractal dimension influence SFCTB's strength features to varying degrees. This study employs CT technology and 3D images to achieve quantitative and visual characterization of the spatial distribution of pores, fractures, and SFCTB after failure. It provides a novel approach for revealing the microscopic mechanism underlying the mechanical properties of SFCTB.

地下回填体系的加固性能非常重要，所有荷载都作用于其上。采用钩端型（HE）、熔融萃取型（ME）和卷曲型(C)三种钢纤维，添加量为2.0%，制备固含量为70 wt%、胶尾比为1:4的CTB试样。采用单轴压缩试验对钢纤维增强钨尾胶结充填体（SFCTB）的宏观强度特征进行了评价。采用x射线计算机断层扫描（CT）技术考察了孔隙度、断裂特征和不同类型钢纤维掺入对CTB强度的影响。实验结果表明，加入钢纤维可以增强孔隙结构，有效地改善孔隙形态。添加HE和ME钢纤维可以抑制SFCTB的裂缝发育，提高SFCTB的承载能力，但导致裂缝体积分别增加0.84%和0.76%。相比之下，C钢纤维的断裂体积减小了0.47%，显著抑制了断裂扩展，提高了抗压强度。HE和C钢纤维的掺入使三维孔隙率（P3D）分别降低0.054%和0.046%，ME钢纤维的掺入使P3D提高0.372%。孔隙率、裂纹分布、三维分形维数等关键因素对SFCTB的强度特征有不同程度的影响。本研究采用CT技术和3D图像技术，对孔隙、裂缝和破坏后SFCTB的空间分布进行定量、可视化表征。它为揭示SFCTB力学性能的微观机制提供了一种新的方法。

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引用次数: 0

A new representation of the grinding equation adapted to agglomeration processes using experiments on Ni and Al powders 通过对Ni和Al粉末的实验，提出了一种适用于团聚过程的研磨方程

IF 4.6 2区工程技术 Q2 ENGINEERING, CHEMICAL

Powder Technology

Pub Date : 2025-12-29 DOI: 10.1016/j.powtec.2025.122095

Oleg V. Lapshin, Evgeny N. Boyangin

In this research, a new phenomenological equation is proposed that describes in a macroscopic approximation the combined processes of grinding and agglomeration in a binary mixture during its mechanical treatment. Experimental studies of low-energy mechanical activation of a nickel and aluminum powder mixture are carried out. The main feature of the studied system is the simultaneous occurrence of two competing processes: grinding of the initial particles and agglomeration of the resulting smaller fragments. This phenomenon is a serious problem for creating adequate mathematical models describing the change in particle size during treatment. We propose a solution to this problem based on a modification of the existing equation conventionally used to describe the kinetics of grinding. Instead of considering the grinding process as a single phenomenon, it is proposed to divide it into two parts: the grinding of the initial large particles and the competing process of agglomeration caused by the adhesion of small particles into larger aggregates. Such a division allows us to build a more accurate model. Good agreement between the proposed equation and the experimental results is shown. The obtained results have practical significance for various fields requiring precise control of the sizes and properties of powder materials.

本文提出了一个新的现象学方程，以宏观近似描述二元混合物在力学处理过程中的研磨和团聚联合过程。对镍铝粉混合物进行了低能机械活化实验研究。所研究系统的主要特点是同时发生两个相互竞争的过程：初始颗粒的研磨和产生的较小碎片的团聚。对于建立描述处理过程中粒径变化的适当数学模型来说，这种现象是一个严重的问题。我们提出了一个解决这个问题的基础上修改现有的方程，通常用于描述动力学的磨削。不将磨矿过程视为单一现象，而是将其分为两个部分：初始大颗粒的磨矿过程和小颗粒粘附形成较大团聚体的团聚竞争过程。这样的划分使我们能够建立一个更精确的模型。所得方程与实验结果吻合较好。所得结果对需要精确控制粉体材料粒度和性能的各个领域具有实际意义。

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引用次数: 0

Microstructure engineering endows CL-20/FOX-7/Al high-energy micro-units with enhanced safety and energy release 微观结构工程赋予CL-20/FOX-7/Al高能微单元更高的安全性和能量释放能力

IF 4.6 2区工程技术 Q2 ENGINEERING, CHEMICAL

Powder Technology

Pub Date : 2025-12-27 DOI: 10.1016/j.powtec.2025.122062

Wenqing Li , Xiaoying Cheng , Shimin Zhang , Chenhe Feng , Xinhao Lu , Songchao Shi , Xiaohong Yan , Ligang Zhang , Chongwei An , Baoyun Ye

To simultaneously achieve high energy density, rapid energy release, and high safety, this work adopts CL-20/FOX-7 as a high-energy oxidizer and nano-Al as a metal fuel, and proposes a “fuel-oxidizer integration and microstructure tailoring” design strategy. Four architecturally tunable CL-20/FOX-7/Al energetic micro-units were fabricated via microchannel recrystallization. The effects of binder type and rheological properties on droplet solidification and microstructure evolution were systematically investigated, and a formation mechanism was elucidated in which solvent exchange, skeletal support, and shrinkage cooperatively determine the final architecture of the micro-units. The results show that all micro-units exhibit excellent hydrophobicity and good flowability. The mechanical safety of micro-units with hollow-porous and dense structures is significantly enhanced, and the sensitivity of micro-units with different structures to external stimuli is selective. DSC/TG-FTIR demonstrate that the coupling of CL-20/FOX-7 decomposition with Al oxidation is architecture dependent; in C/F/Al/F, the advance of Al-related exotherms originates from the synergistic effect of HF released from F₂₆₀₂ with the hollow-porous framework and the co-located n-Al. Combustion tests and residue characterization further demonstrate that delivers the fastest pressurization rate and the finest, highly porous residues, whereas the dense exhibits intense micro-explosions and a large flame envelope, both clearly outperforming the mechanically mixed sample. Overall, this study establishes a clear structure–performance relationship for CL-20/FOX-7/Al fuel-oxidizer integrated micro-units and provides a new pathway for microstructure-engineered design of high-energy, high-safety energetic particles and advanced solid propellant systems.

为了同时实现高能量密度、快速释放能量和高安全性，本工作采用CL-20/FOX-7作为高能氧化剂，纳米al作为金属燃料，提出了“燃料-氧化剂一体化和微观结构定制”的设计策略。采用微通道再结晶法制备了4个结构可调的CL-20/FOX-7/Al能量微单元。系统研究了粘结剂类型和流变学性质对液滴凝固和微观组织演变的影响，阐明了溶剂交换、骨架支撑和收缩共同决定微单元最终结构的形成机制。结果表明，各微单元均具有优异的疏水性和良好的流动性。空心多孔致密结构微单元的力学安全性显著增强，不同结构微单元对外部刺激的敏感性具有选择性。DSC/TG-FTIR表明CL-20/FOX-7分解与Al氧化的耦合与结构有关；在C/F/Al/F中，Al相关放热的推进源于F2602释放的HF与空孔框架和共位的n-Al的协同作用。燃烧测试和残留物表征进一步表明，该方法提供了最快的加压速率和最细的、高度多孔的残留物，而致密样品则表现出强烈的微爆炸和大的火焰包层，两者都明显优于机械混合样品。总体而言，本研究为CL-20/FOX-7/Al燃料氧化剂集成微单元建立了清晰的结构-性能关系，为高能、高安全高能粒子和先进固体推进剂系统的微结构工程设计提供了新的途径。

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引用次数: 0

Optimal control of batch cooling crystallization under considering nucleation uncertainty 考虑成核不确定性的间歇冷却结晶优化控制

IF 4.6 2区工程技术 Q2 ENGINEERING, CHEMICAL

Powder Technology

Pub Date : 2025-12-27 DOI: 10.1016/j.powtec.2025.122083

Fangkun Zhang , Chuan Li , Aozhe Meng , Baoming Shan , Xuezhong Wang , Qilei Xu

Nucleation control remains a critical challenge in industrial batch crystallization, as inherent uncertainties in nucleation significantly affect crystal size distribution (CSD), leading to inconsistent product quality-especially in unseeded processes. To address the uncertainty of initial CSD caused by stochastic primary nucleation, this study proposes a nested optimization-evaluation framework that combines the whale optimization algorithm with Bayesian optimization to derive a robust cooling profile. A minimizing nucleation strategy based on three-stage gradient cooling was introduced to suppress stochastic nucleation during cooling crystallization. This strategy substantially reduces the impact of primary and secondary nucleation uncertainty and improves batch-to-batch consistency of product crystals. The effectiveness of the proposed method was validated in a typical batch cooling crystallization system under primary and secondary nucleation uncertainties. Simulation results demonstrate that this robust optimization approach effectively mitigates the influence of primary nucleation uncertainty on the CSD. Compared with conventional linear cooling, the volume and number of fine crystals were reduced by 60.81 % and 90 %, respectively. Moreover, approximately 90 % of fine crystals were eliminated, resulting in notable enhancements in both product quality and process controllability. This work holds considerable importance for addressing uncertainties in nucleation control during crystallization processes and ensuring batch-to-batch product consistency, particularly in unseeded crystallization systems.

成核控制仍然是工业间歇结晶的一个关键挑战，因为成核固有的不确定性会显著影响晶体尺寸分布（CSD），导致产品质量不一致，特别是在无种子工艺中。为了解决随机初核引起的初始CSD的不确定性，本研究提出了一个嵌套优化评估框架，该框架将鲸鱼优化算法与贝叶斯优化相结合，以获得稳健的冷却轮廓。为了抑制冷却结晶过程中的随机成核，提出了一种基于三级梯度冷却的最小化成核策略。这种策略大大减少了一次和二次成核不确定性的影响，提高了产品晶体的批次一致性。在一个典型的间歇冷却结晶系统中验证了该方法在一次和二次成核不确定性下的有效性。仿真结果表明，这种鲁棒优化方法有效地减轻了初成核不确定性对CSD的影响。与常规线性冷却相比，细晶的体积和数量分别减少了60.81%和90%。此外，约90%的细晶被消除，从而显著提高了产品质量和过程可控性。这项工作对于解决结晶过程中成核控制的不确定性和确保批间产品一致性具有相当重要的意义，特别是在非种子结晶系统中。

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引用次数: 0

Three-dimensional dynamics of vortex structures in granular materials 粒状材料中涡旋结构的三维动力学

IF 4.6 2区工程技术 Q2 ENGINEERING, CHEMICAL

Powder Technology

Pub Date : 2025-12-27 DOI: 10.1016/j.powtec.2025.122081

Yichuan Zhu , Zenon Medina-Cetina , Chao Wang , Xiong Bi

By coupling three-dimensional digital image correlation (3D-DIC) with triaxial compression tests, we directly observed and quantified the spatio-temporal evolution of 3D vortex structures in granular materials. 3D residual displacement fields were analyzed in both Cartesian and cylindrical coordinate systems, and an algorithm was developed to identify its vortex properties, including their centers, radii, circulation, and strength. Findings indicate that transient, small-scale vortices present before peak stress give way to persistent, co-rotating vortices aligning with shear bands during material softening. While the number of vortices decreased post-softening, their size and strength significantly increased. The study further elucidates the co-evolution of 3D vortices with other strain localization phenomena, including volumetric expansion and dilation zones, and details how micro-band collisions and intensified rotational behavior lead to persistent shear band formation. The work provides the first comprehensive experimental insight into 3D vortex dynamics and their crucial role in the micro-deformation mechanisms of granular media, offering a foundation for future experimental and numerical investigations.

通过将三维数字图像相关（3D- dic）与三轴压缩试验相结合，直接观察并量化了颗粒状材料中三维涡旋结构的时空演变。在直角坐标系和柱坐标系下对三维残余位移场进行了分析，并开发了一种识别其涡旋特性的算法，包括涡旋的中心、半径、循环和强度。研究结果表明，在材料软化过程中，峰值应力之前出现的瞬态小尺度涡旋会让位于与剪切带对齐的持续、同向旋转涡旋。软化后涡旋的数量减少，但涡旋的大小和强度显著增加。该研究进一步阐明了三维涡旋与其他应变局部化现象（包括体积膨胀和膨胀区）的共同演化，并详细说明了微带碰撞和强化的旋转行为如何导致持续剪切带的形成。这项工作首次提供了对三维涡旋动力学及其在颗粒介质微变形机制中的关键作用的全面实验见解，为未来的实验和数值研究奠定了基础。

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引用次数: 0