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Effect of turbulent fluctuation on the ignition of millimeter particle:Experimental studies and numerical modelling with a new correlation of nusselt number Author links open overlay panel

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Particuology 2024年第8期91卷 168-175页

作者： lele feng Jie Liu Haihui Xin Liangliang Jiang Yuxin Wu Saeideh Babaee Jiangsu Key Laboratory of Coal-based Greenhouse Gas Control and Utilization China University of Mining and TechnologyXuzhou221008China School of Safety Engineering China University of Mining and TechnologyXuzhou221116China Key Laboratory of Hubei Province for Coal Conversion and New Carbon Materials Wuhan University of Science and TechnologyWuhan430000China Department of Chemical and Petroleum Engineering University of CalgaryCalgaryAlbertaCanada Department of Energy and Power Engineering Tsinghua UniversityBeijing100084China Department of Chemical and Metallurgical Engineering University of the WitwatersrandJohannesburgSouth Africa

Understanding the influencing mechanism of turbulent fluctuation on the ignition characteristics of millimeter coal particles is *** this work,to study the effect of turbulent fluctuation on ignition time,millimeter coal particles are subjected to a specific flow field,generated in a furnace with symmetric fans.A one-dimensional model with the new proposed correlation and the Ranz-Marshall(R-M)correlation for Nu(Nusselt number)is established to simulate the coal ignition *** addition,the effects of fan speed,temperature,particle diameter,particle distance and coal type on the ignition time are *** is found that an increase in fan speed from 0 to 3000 rpm leads to a particle Reynolds number Re_(p)increase from 0 to 22.5,and a turbulent particle Reynolds number Re_(t)*increase from 0 to *** a consideration of the fluctuation effect,the new correlation of Nu gives a better prediction of ignition time compared to the R-M ***,the ignition time is revealed to decrease with an increasing fan speed and an elevating *** the ignition time shows merely an initial boost with enlarging particle distance,it exhibits a linearity with the term of particle diameter dp1.3-1.7 and Reynolds numbers(Nu*/Nu)-0.6(Nu*is turbulent Nusselt number).Based on this relationship,the difference of predicted ignition time is calculated at different Re_(p)and Re_(t)*.It is shown that at low Re_(p)or high Re_(t)*values,the new correlation should substitute for the R-M correlation.

关键词： Turbulent fluctuation Particle heat transfer Empirical correlation Coal ignition

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MILD粉体燃烧技术研究进展与关键问题分析

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煤炭学报 2024年第1期49卷 224-234页

作者：吕俊复冯乐乐吴玉新张海清华大学热科学与动力工程教育部重点实验室北京100084 中国矿业大学安全工程学院江苏徐州221116

MILD燃烧是一种在中度或极度低氧环境下发生的温和燃烧模式,兼具高燃烧热利用率和极低NOx排放的优势,国际燃烧领域认为它是拥有巨大应用潜力的清洁燃烧技术之一。自1990年左右开展相关研究以来,对于实现气体燃料的MILD燃烧的相关技术已... 详细信息

MILD燃烧是一种在中度或极度低氧环境下发生的温和燃烧模式,兼具高燃烧热利用率和极低NOx排放的优势,国际燃烧领域认为它是拥有巨大应用潜力的清洁燃烧技术之一。自1990年左右开展相关研究以来,对于实现气体燃料的MILD燃烧的相关技术已相对成熟,而关于煤粉和生物质等固体燃料的MILD燃烧机制和实现条件的研究仍相对缺乏。基于高动量氧化剂射流来实现内部再循环,不再需要外部高温预热来建立MILD燃烧,极大拓宽了MILD燃烧的应用范围。从颗粒弥散、受热、着火、燃烧、污染物等方面概述了MILD粉体燃料燃烧的基础特性,由于颗粒的不均匀弥散和反应,煤粉等碳基固体燃料的MILD燃烧进程较气体燃料更复杂。高速射流MILD燃烧在增加点火延迟的同时也扩展了点火区和反应区,需要对燃烧各阶段的特征和机理开展系统研究。介绍了固体燃料MILD燃烧理论设计和装备研发领域所取得的研究成果,建议通过高精度数值模拟,改进现有燃煤锅炉燃烧器、调节工艺参数以匹配MILD燃烧模式,增加焦炭颗粒的停留时间以提高燃烬率,提高燃烧稳定性并抑制包括细颗粒物在内的各类污染物排放。基于互联能源系统的整体方法,推进MILD燃烧与各类新型燃烧技术的耦合研究,尤其加强煤粉、生物质与氢、氨等可燃气体共燃特性研究,助力能源转型。探究粉体MILD燃烧中的湍流两相流特征、湍流相间传热作用以及湍流-化学耦合作用是加深对粉体MILD燃烧理解的关键,涉及多变量分析和高精度模拟,是未来研究的重点和难点。

关键词：低氧稀释燃烧(MILD) 高速射流煤燃烧污染物湍流

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湍流热环境中毫米级木质生物质颗粒燃烧特性

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洁净煤技术 2024年第6期30卷 36-46页

作者：郭慧娜吴玉新冯乐乐刘杰清华大学能源与动力工程系北京100084 中国矿业大学安全工程学院江苏徐州221116

燃煤机组耦合生物质甚至全燃生物质是高效低成本降碳的可行技术。生物质燃料破碎能耗高导致入炉粒径相对较大,部分大粒径颗粒在炉内高温湍流环境中的燃尽问题值得重视。采用四风扇对冲高温湍流实验装置,构造近均匀各向同性湍流流场。以... 详细信息

燃煤机组耦合生物质甚至全燃生物质是高效低成本降碳的可行技术。生物质燃料破碎能耗高导致入炉粒径相对较大,部分大粒径颗粒在炉内高温湍流环境中的燃尽问题值得重视。采用四风扇对冲高温湍流实验装置,构造近均匀各向同性湍流流场。以两种粒径的木质生物质颗粒(d_(p,0)=2.5、6.0 mm)为研究对象,通过改变炉温(T_(gas)=500、700、900℃)和湍流脉动速度(u_(rms)=0~1.8 m/s),研究湍流脉动速度urms对毫米级生物质颗粒燃烧特性的影响。试验通过颗粒表面-中心温度测量系统记录了颗粒温度,通过彩色图像测量系统捕捉燃烧全过程,确定不同工况下生物质颗粒的燃烧时间、着火模式、火焰形态及粒径变化。结果表明,生物质颗粒通常倾向于发生均相着火,仅在T_(gas)=500℃时增大u_(rms)使着火模式由均相着火转变为异相着火。u_(rms)增至1.8 m/s,着火前颗粒升温速率提高了近30%,挥发分燃烧阶段颗粒表面温度升高约300℃。u_(rms)增加引起挥发分火焰锋面褶皱变形,均相燃烧强度增加,tvol略微缩短;生物质焦炭的孔隙发展更加迅速,大量氧气扩散进颗粒内发生反应,使焦炭燃尽时间大幅缩短40%以上,焦炭燃烧温度亦随之增加。颗粒湍流雷诺数Re_(p,t)越大,受湍流脉动影响越显著。升高炉温,增大u_(rms)对颗粒温度的影响将减弱,对缩短燃烧时间的影响越强烈。

关键词：均匀各向同性湍流生物质能源单颗粒燃烧湍流热环境

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Classification performance of model coal mill classifiers with swirling and non-swirling inlets

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Chinese Journal of Chemical Engineering 2020年第3期28卷 777-784页

作者： lele feng Hai Zhang Lilin Hu Yang Zhang Yuxin Wu Yuzhao Wang Hairui Yang Department of Energy and Power Engineering Tsinghua UniversityBeijing 100084China Chengde Petroleum College Chengde 067000China

The classification performance of model coal mill classifiers with different bottom incoming flow inlets was experimentally and numerically *** flow field adjacent to two neighboring impeller blades was measured using the particle image velocimetry *** results showed that the flow field adjacent to two neighboring blades with the swirling inlet was significantly different from that with the non-swirling *** the swirling inlet,there was a vortex located between two neighboring blades,while with the nonswirling inlet,the vortex was attached to the blade *** vorticity of the vortex with the non-swirling inlet was much lower than that with the swirling *** classifier with the non-swirling inlet demonstrated a larger cut size than that with the swirling inlet when the impeller was stationary(~0 r·min-1).As the impeller rotational speed increased,the cut size of the cases with non-swirling and swirling inlets both decreased,and the one with the non-swirling inlet decreased more *** values of the cut size of the two classifiers were close to each other at a high impeller rotational speed(≥120 r·min-1).The overall separation efficiency of the classifier with the non-swirling inlet was lower than that with the swirling inlet,and monotonically increased as the impeller rotational speed *** the swirling inlet,the overall separation efficiency first increased with the impeller rotational speed and then decreased when the rotational speed was above 120 r·min-1,and the variation trend of the separation efficiency was more *** the initial particle concentration increased,the cut sizes of both swirling and non-swirling inlet cases decreased first and then barely *** a low initial particle concentration(b 0.04 kg·m-3),the classifier with the swirling inlet had a larger cut size than that with the non-swirling inlet.

关键词： Coal mill classifier Cut size Non-swirling inlet Particle image velocimetry Impeller rotational speed

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Convolutional neural network adaptation and optimization method in SIMT computing mode

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The Journal of China Universities of Posts and Telecommunications 2024年第2期31卷 105-112页

作者： feng Zhenfu Zhang Yaying Yang lele Xing Lidong School of Electronic Engineering Xi'an University of Posts and TelecommunicationsXi'an 710121China

For studying and optimizing the performance of general-purpose computing on graphics processing units(GPGPU)based on single instruction multiple threads(SIMT)processor about the neural network application,this work contributes a self-developed SIMT processor named Pomelo and correlated assembly *** parallel mechanism of SIMT computing mode and self-developed Pomelo processor is briefly introduced.A common convolutional neural network(CNN)is built to verify the compatibility and functionality of the Pomelo *** computing flow with task level and hardware level optimization is adopted on the Pomelo processor.A specific algorithm for organizing a Z-shaped memory structure is developed,which addresses reducing memory access in mass data computing *** the above-combined adaptation and optimization strategy,the experimental result demonstrates that reducing memory access in SIMT computing mode plays a crucial role in improving performance.A 6.52 times performance is achieved on the 4 processing elements case.

关键词： parallel computing single instruction multiple threads(SIMT) convolutional neural network(CNN) memory optimization

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基于深度强化学习的铁路更新维护计划

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电子设计工程 2024年第17期32卷 40-44页

作者：白宏权吕和平李宝峰冯乐乐国能朔黄铁路发展有限责任公司山西原平034100 国能铁路装备有限责任公司沧州分公司河北沧州061100

基于提高铁路网络的可靠性和安全性,同时降低成本的目的,采用了基于深度强化学习(DRL)的铁路维护和更新规划方法,通过考虑成本效益和风险降低,在规划周期内优化更新和维护规划,考虑预测性维护和基于条件的维护任务,并将时间、资源和相... 详细信息

基于提高铁路网络的可靠性和安全性,同时降低成本的目的,采用了基于深度强化学习(DRL)的铁路维护和更新规划方法,通过考虑成本效益和风险降低,在规划周期内优化更新和维护规划,考虑预测性维护和基于条件的维护任务,并将时间、资源和相关工程约束纳入模型中,以捕捉问题的实际特征,采用双重深度Q网络(DDQN)来克服环境的不确定性,应用优先回放记忆来改善反馈。提出的DDQN方法被应用于一家货运铁路网络,分析结果表明,所提出的方法可以制定出一种最优策略,不仅可以减少预算消耗,还可以提高网络的可靠性和安全性。

关键词：铁路更新铁路维护深度强化学习双重深度Q网络

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生活垃圾焚烧飞灰处理技术研究进展

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化工进展 2024年第7期43卷 4102-4117页

作者：孔祥蕊董玥岑张蒙雨王彪尹水娥陈冰陆家纬张媛冯乐乐王洪涛徐海云中国城市建设研究院有限公司北京100120 清华大学环境学院北京100084 中城院(北京)环境科技股份有限公司北京100120 中国矿业大学安全工程学院江苏徐州221116

焚烧是我国生活垃圾最主要的处置手段,焚烧飞灰含有二噁英和重金属,属于危险废物,处理方式比较受限,但处理需求量大。推动生活垃圾焚烧飞灰无害化处置与资源化利用处理技术的发展,积极补齐城镇生活垃圾处理设施短板,符合国家节能减排与... 详细信息

焚烧是我国生活垃圾最主要的处置手段,焚烧飞灰含有二噁英和重金属,属于危险废物,处理方式比较受限,但处理需求量大。推动生活垃圾焚烧飞灰无害化处置与资源化利用处理技术的发展,积极补齐城镇生活垃圾处理设施短板,符合国家节能减排与绿色发展的要求。本文系统分析了我国典型地区生活垃圾焚烧飞灰基础特性、二噁英和重金属产生特征,综述了飞灰二噁英的主要处理技术,包括高温烧结、高温熔融/玻璃化、水泥回转窑热处理、低温催化热解、水热处理技术、机械化学降解技术,对比了飞灰中重金属的主要处理方法,包括固化稳定化、固热处理、金属分离技术,并对飞灰处理技术的工程化应用进行总结与展望,以期为我国生活垃圾焚烧飞灰减量化、无害化、资源化技术发展提供理论支撑。

关键词：生活垃圾焚烧飞灰二噁英重金属

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电液伺服控制阀动态仿真与试验

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四川职业技术学院学报 2024年第4期34卷 154-157页

作者：张继红张继明冯乐乐蔡春堂蒋志刚四川职业技术学院智能制造学院四川遂宁629000 国家能源集团铁路装备有限责任公司北京海淀100089

电液伺服阀被广泛应用各种自动化装备中,这种复杂的机电控制系统集机、电、液、磁于一体,属于重要的随动跟踪控制元件,伺服控制除了有良好的静态性能外,其动力学特性决定了伺服系统工作精度.运用键合图理论建立电液伺服阀的键图模型;推... 详细信息

电液伺服阀被广泛应用各种自动化装备中,这种复杂的机电控制系统集机、电、液、磁于一体,属于重要的随动跟踪控制元件,伺服控制除了有良好的静态性能外,其动力学特性决定了伺服系统工作精度.运用键合图理论建立电液伺服阀的键图模型;推导模型的状态空间方程和输出方程;运用仿真软件MATLAB/Simulink进行了仿真,分析电液伺服阀系统动态特性.最后在搭建的实验验证平台上验证了系统的动态性能,并与仿真结果进行了比较分析.结果是该电液伺服阀的动态特性指标超调量40%、响应时间13ms、上升时间2ms左右.

关键词：电液伺服阀 MATLAB/Simulink 建模与仿真动态性能试验

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Characterization of metabolic reprogramming and immune infiltration in colorectal cancer

Characterization of metabolic reprogramming and immune infil...

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2021年中国肿瘤标志物学术大会暨第十五届肿瘤标志物青年科学家论坛

作者： Ruofei Tian lele feng Fourth Military Medical University 中国人民解放军空军军医大学第一附属医院

Purpose: To construct a metabolic-related gene prognostic index(MRGPI) for colorectal cancer(CRC) and make a full analysis of the relationship between metabolic reprogramming and immune infiltration in colorectal *** and methods: Based on The Cancer Genome Atlas(TCGA) dataset(COAD, n = 514), 5 survival-related metabolic genes were identified by the Cox regression analysis. Subsequently,MRGPI was constructed by the 5 survival-related metabolic genes and validated with the Gene Expression Omnibus(GEO) dataset(GSE39582, n = 585). Meanwhile, gene set variation analysis(GSVA) and cibersort analysis were used to comprehensively analyze the metabolic reprogramming and immune infiltration of colorectal cancer. CPT2 was selected by combining the 5 survival-related metabolic genes and metabolic reprogramming result. Afterwards, enrichment analysis, weighted gene coexpression network analysis(WGCNA) and immune infiltration analysis were performed to fully explore the function of ***: Five survival-related metabolic genes including ACOX1, ASNS, CPT2, FOLR1 and GCNT3 were selected by the Cox regression analysis and MRGPI was constructed by the 5 survival-related metabolic genes. In TCGA cohort, MRGPI-high patients had a better overall survival(OS) than MRGPI-low patients, consistent with the results in the GEO cohort. The metabolic reprogramming of colorectal cancer(CRC) showed that top 3 down-regulated pathways were Fatty Acids Oxidation(peroxisomal), Fatty Acids Oxidation(mitochondrial), Carnitine shuttle, and top 3 upregulated pathways were Purine Biosynthesis, Pyrimidine Biosynthesis, Histone ***, immune infiltration analysis suggested that Carnitine shuttle, Fatty Acids Oxidation(peroxisomal) and Fatty Acids Oxidation(mitochondrial) were positively correlated with plasma cells and na?ve B cells. Purine Biosynthesis and Pyrimidine Biosynthesis were negatively correlated with plasma cells and na?ve B cells. 5 survival-related metabolic

关键词： colorectal cancer(CRC) prognostic model metabolic reprogramming immune infiltration CPT2

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Self-healable gels in electrochemical energy storage devices

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Nano Research 2024年第4期17卷 3302-3323页

作者： Yang Li PeiPei Ding Yuzhe Gu Sheng Qian Yuncong Pang lele Wang Jiayang feng Baoguang Liu Qi Wan Ping Li Zhiwei Liu College of Electronic and Optical Engineering&College of Flexible Electronics(Future Technology) Nanjing University of Posts&Telecommunications(NJUPT)Nanjing 210023China State Key Laboratory of Organic Electronics and Information Displays&Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials(IAM)Nanjing University of Posts and Telecommunications(NJUPT)Nanjing 210023China College of Materials Science&Engineering Beijing University of TechnologyBeijing 100124China Beijing Advanced Innovation Center for Materials Genome Engineering Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China Pillar of Engineering Product Development Singapore University of Technology and DesignSingapore 487372Singapore School of Energy and Environmental Engineering University of Science and Technology BeijingBeijing 100083China

In the green energy and carbon-neutral technology,electrochemical energy storage devices have received continuously increasing attention ***,due to the unavoidable volume expansion/shrinkage of key materials or irreversible mechanical damages during application,the stability of energy storage and delivery as well as the lifetime of these devices are severely shortened,leading to serious performance degradation or even safety ***,the utilization of self-healable gels into electrochemical energy storage devices,such as electrodes,binders,and electrolytes,is proven as an effective method to realize long-term stable operation of these devices via the self-repairing of mechanical and electrochemical ***,this review first summarizes the feature and fabrication of different gels,paying special attention to hydrogels,organohydrogels,and ***,basic concepts and figure of merit of self-healable gels are analyzed with a detailed discussion at the healing mechanisms,from reversible dynamic bonds to physical molecular diffusion,and to external healing *** we introduce all the important parts of electrochemical energy storage devices,which could be replaced by healable gels to enhance the durability,including electrodes,binders,and ***,the critical challenges and future perspectives regarding the future development of healable gels based high-performance electrochemical energy storage devices or electronics are provided.

关键词： self-healable gels healing mechanisms electrodes binders gel electrolytes

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