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Lattice Boltzmann method for simulating particle-fluid interactions

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Particuology 2010年第6期8卷 539-543页

作者： Liang-Shih fan Department of Chemical and Biomolecular Engineering The Ohio State UniversityColumbusOH 43210USA

The lattice Boltzmann method （LBM） has gained increasing popularity in the last two decades as an alternative numerical approach for solving fluid flow problems. One of the most active research areas in the LBM is its application in particle-fluid systems, where the advantage of the LBM in efficiency and parallel scalability has made it superior to many other direct numerical simulation （DNS） techniques. This article intends to provide a brief review of the application of the LBM in particle-fluid systems. The numerical techniques in the LBM pertaining to simulations of particles are discussed, with emphasis on the advanced treatment for boundary conditions on the particle-fluid interface. Other numerical issues, such as the effect of the internal fluid, are also briefly described. Additionally, recent efforts in using the LBM to obtain closures for particle-fluid drag force are also reviewed.

关键词： Particle-fluid flow Drag force Lattice Boltzmann method (LBM) Numerical simulation Adaptive mesh refinement (AMR) Immersed boundary method

Dental pulp regeneration strategies:A review of status quo and recent advances

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Bioactive Materials 2024年第8期38卷 258-275页

作者： xin-Lu Li Wei fan Bing fan The State Key Laboratory of Oral&Maxillofacial Reconstruction and Regeneration Key Laboratory of Oral Biomedicine Ministry of EducationHubei Key Laboratory of StomatologySchool&Hospital of StomatologyWuhan University237 Luoyu Road430079WuhanChina

Microorganisms,physical factors such as temperature or mechanical injury,and chemical factors such as free monomers from composite resin are the main causes of dental pulp *** clinical treatment methods for pulp diseases include the root canal therapy,vital pulp therapy and regenerative endodontic *** endodontic therapy serves the purpose of inducing the regeneration of new functional pulp tissues through autologous revascularization or pulp tissue *** article first discusses the current clinical methods and reviews strategies as well as the research outcomes regarding the pulp *** the in vivo models,the prospects and challenges for regenerative endodontic therapy were further discussed.

关键词： Pulp regeneration Revascularization Scaffold Growth factor Cell-homing

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基于伪标签算法的地震事件分类识别方法研究

地震工程学报 2025年第1期47卷 160-167,177页

作者：范晓易王夫运陈飞陈传华江苏省地震局南京地震监测中心站江苏南京210000 中国地震局地球物理勘探中心河南郑州450000 山东省地震局泰安地震监测中心站山东泰安271000

将伪标签算法引入地震类型识别领域,并设计伪标签神经网络法程序,对山东地区2019—2021年M L1.5以上的天然地震、爆破地震、塌陷地震三类事件开展试验。使用优选的有标签样本集预测无标签样本,将其标记为伪标签样本后加入联合训练,并对... 详细信息

将伪标签算法引入地震类型识别领域,并设计伪标签神经网络法程序,对山东地区2019—2021年M L1.5以上的天然地震、爆破地震、塌陷地震三类事件开展试验。使用优选的有标签样本集预测无标签样本,将其标记为伪标签样本后加入联合训练,并对比传统BP神经网络法和支持向量机法,以初步验证伪标签算法在地震类型识别领域的可行性和在小样本条件下的适用性。试验结果表明:影响伪标签神经网络法分类效果的主要因素有已知样本数量和伪标签样本占比。当已知样本数量介于60~120个、伪标签样本占比20%~30%时,其识别效果最佳。在小样本条件下,伪标签神经网络法的识别率相较于传统BP神经网络法提高了2%~8%,与支持向量机法的识别率差值集中在±4%以内。因此,采用伪标签算法弥补部分地区样本库匮乏的不足,实现小样本地震类型识别,具备一定的应用价值。

关键词：伪标签算法地震类型识别神经网络法小样本

Active generalized predictive control of turbine tip clearance for aero-engines

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Chinese journal of Aeronautics 2013年第5期26卷 1147-1155页

作者： Peng Kai fan Ding Yang fan Fu Qiang Li Yong School of Power and Energy Northwestern Polytechnical University Aeronautics and Astronautics Engineering College Air Force Engineering University School of Flight Technology Civil Aviation Flight University of China

Active control of turbine blade tip clearance continues to be a concern in design and control of gas turbines. Ever increasing demands for improved efficiency and higher operating temperatures require more stringent tolerances on turbine tip clearance. In this paper, a turbine tip clearance control apparatus and a model of turbine tip clearance are proposed; an implicit active generalized predictive control （GPC）, with auto-regressive （AR） error modification and fuzzy adjustment on control horizon, is presented, as well as a quantitative analysis method of robust per- turbation radius of the system. The active clearance control （ACC） of aero-engine turbine tip clear- ance is evaluated in a lapse-rate take-off transient, along with the comparative and quantitative analysis of the stability and robustness of the active tip clearance control system. The results show that the resultant active tip clearance control system with the improved GPC has favorable steadystate and dynamic performance and benefits of increased efficiency, reduced specific fuel consump- tion, and additional service life.

关键词： Active clearance control(ACC) Aero-engine Aircraft Generalized prcdictivc control (GPC) Global convergence Robust perturbation radius Turbine tip clearance

考虑碳排放优化的多层随机模型预测的配电网新能源电压控制方法

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供用电 2025年第1期42卷 72-78页

作者：宋美琪李洪全武浩范岳张鹏商和龙丁浩范宏进国网冀北电力有限公司智能配网中心河北秦皇岛066100 山东电工电气集团新能科技有限公司山东济南250101 山东大学电气工程学院山东济南250061

“电力零碳”是实现“双碳”目标的重要支撑,采用可再生能源发电是实现“电力零碳”的重要举措。电力高比例可再生能源接入配电网给配电网电压控制带来了巨大挑战。同时,风能场站等可再生能源具有高随机性和间歇性等特点,传统电压控制... 详细信息

“电力零碳”是实现“双碳”目标的重要支撑,采用可再生能源发电是实现“电力零碳”的重要举措。电力高比例可再生能源接入配电网给配电网电压控制带来了巨大挑战。同时,风能场站等可再生能源具有高随机性和间歇性等特点,传统电压控制方法在高比例可再生能源渗透的情景下无法取得满意的控制效果。为解决以上电压控制问题,提出了一种基于双层随机模型预测控制的电压控制方法。在所提方法中,变压器和并联电容在上层以小时为周期进行控制,而下层控制器以15 min为控制周期对分布式发电(distributed generation,DG)的输出进行调节。所提方法综合了模型预测控制和随机优化的优点,能实现有效的电压控制效果,并降低碳排放。基于改进IEEE 33节点系统中的仿真结果表明,所提方法能有效协调不同的电压调节设备,在高随机性可再生能源渗透下能取得良好的电压控制效果,保证配电网运行的经济性,有效降低配电网络运行的碳排放。

关键词：配电网电压控制碳排放随机模型预测控制分布式发电

Spatially distributed damage in sandstone under stress-freeze-thaw coupling conditions

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journal of Rock Mechanics and Geotechnical Engineering 2022年第6期14卷 1910-1922页

作者： Lifeng fan Yiding fan Yan xi jingwei Gao College of Architecture and Civil Engineering Beijing University of TechnologyBeijing100124China

In the present study,we tried to understand the spatially distributed damage in sandstone samples under the coupled stress-freeze-thaw(SFT)***,uniaxial compressive stresses(i.e.0 MPa,10 MPa,20 MPa,and 25 MPa)were applied to the samples,and then freeze-thaw(FT)cycles(0,8,16,and 24)were performed on the uniaxially stressed samples to realize the SFT ***,real-time CT scanning was conducted to observe the induced *** total porosity was introduced to quantitatively evaluate the damage *** local porosity variation,with the distance from the center of the sandstone sample,was analyzed to understand the spatial distribution of ***,the coupling effects of SFT on the damage gradient were *** results indicate that the porosity rises with FT cycles,and the applied stresses can accelerate the increase in *** damage increases exponentially with the distance from the center of the *** damage presents a spatial gradient distribution,not the commonly used uniform distribution in various *** damage gradient increases with FT cycles,and the increasing rate in damage gradient decreases at uniaxial stress of 0 MPa and 10 MPa first,but the increasing rate in damage gradient increases with FT cycles then at stress increasing to 20 MPa.

关键词： Rock damage Freeze-thaw(FT)cycles Uniaxial stress oupling effects

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道路桥梁钻孔灌注桩施工技术研究

价值工程 2025年第1期44卷 36-38页

作者：范志泉龙岩交通建设集团有限公司龙岩364000

钻孔灌注桩因其适应性强、成本合理、施工便捷,在公路桥梁、港口等工程领域得到广泛应用。然而,其成桩过程复杂,影响质量的因素众多,因此需要严格控制每一环节并全面考虑各种影响因素。本文通过研究东山大桥道路桥梁工程的灌注桩施工,... 详细信息

钻孔灌注桩因其适应性强、成本合理、施工便捷,在公路桥梁、港口等工程领域得到广泛应用。然而,其成桩过程复杂,影响质量的因素众多,因此需要严格控制每一环节并全面考虑各种影响因素。本文通过研究东山大桥道路桥梁工程的灌注桩施工,深入对比分析了旋挖成孔和冲击成孔两种方式的技术特性、工效及成本,旨在为类似工程提供有益参考。通过综合比较不同施工方案,可结合工程需求、施工条件和经济效益,选出最佳方案,进而提升工程质量,降低成本并缩短工期。

关键词：钻孔灌注桩旋挖成孔冲击成孔施工方案

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Utilization of chemical looping strategy in coal gasification processes

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Particuology 2008年第3期6卷 131-142页

作者： Liangshih fan Shwetha Ramkumar Department of Chemical and Biomolecular Engineering The Ohio State UniversityUnited States

Three chemical looping gasification processes, i.e. Syngas Chemical Looping （SCL） process, Coal Direct Chemical Looping （CDCL） process, and Calcium Looping process （CLP）, are being developed at the Ohio State University （OSU）. These processes utilize simple reaction schemes to convert carbonaceous fuels into products such as hydrogen, electricity, and synthetic fuels through the transformation of a highly reactive, highly recyclable chemical intermediate. In this paper, these novel chemical looping gasification processes are described and their advantages and potential challenges for commercialization are discussed.

关键词： Chemical looping Gasification process Combustion Hydrogen

Simulation of 3D parachute fluid–structure interaction based on nonlinear finite element method and preconditioning finite volume method

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Chinese journal of Aeronautics 2014年第6期27卷 1373-1383页

作者： fan Yuxin xia jian College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics

A fluid–structure interaction method combining a nonlinear finite element algorithm with a preconditioning finite volume method is proposed in this paper to simulate parachute transient dynamics. This method uses a three-dimensional membrane–cable fabric model to represent a parachute system at a highly folded configuration. The large shape change during parachute inflation is computed by the nonlinear Newton–Raphson iteration and the linear system equation is solved by the generalized minimal residual（GMRES） method. A membrane wrinkling algorithm is also utilized to evaluate the special uniaxial tension state of membrane elements on the parachute canopy. In order to avoid large time expenses during structural nonlinear iteration, the implicit Hilber–Hughes–Taylor（HHT） time integration method is employed. For the fluid dynamic simulations, the Roe and HLLC（Harten–Lax–van Leer contact） scheme has been modified and extended to compute flow problems at all speeds. The lower–upper symmetric Gauss–Seidel（LUSGS） approximate factorization is applied to accelerate the numerical convergence speed. Finally,the test model of a highly folded C-9 parachute is simulated at a prescribed speed and the results show similar characteristics compared with experimental results and previous literature.

关键词： Flow fields analysis Fluid–structure interaction Nonlinear structural dynam-ics Numerical analysis Parachute inflation