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Experimental and numerical investigations on micromixing performance of multi-orifice cross-flow jet mixers

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Chinese Journal of Chemical Engineering 2024年第6期70卷 63-72页

作者： Hang Yang Zhaojin Lu likun ma Wei Yin Bingjie Wang Zhishan Bai Xiaoyong Yang School of Mechanical and Power Engineering East China University of Science and TechnologyShanghai 200237China

Multi-orifice cross-flow jet mixers(MOCJMs)are used in various industrial applications due to their excellent mixing efficiency,but few studies have focused on the micromixing performance of ***,the flow characteristics and micromixing performance inside the MOCJM were investigated using experiments and computational fluid dynamics(CFD)simulations based on the Villermaux/Dushman system and the finite-rate/modified eddy-dissipation *** optimal A value was correlated with the characteristic parameters of MOCJMs to develop a CFD calculation method applicable to the study of the micromixing performance of the *** the micromixing efficiency was evaluated using the segregation index XS,and the effects of operational and geometric parameters such as mixing flow Reynolds number(ReM),flow ratio(RF),total jet area(ST),the number of jet orifices(n),and outlet configuration on the micromixing efficiency were *** was found that the intensive turbulent region generated by interactions between jets,as well as between jets and crossflows,facilitated rapid *** decreased with increasing ReM and decreasing ***,MOCJMs with lower ST,four jet orifices,and the narrower outlet configuration demonstrated a better micromixing *** study contributes to a deeper understanding of the micromixing performance of MOCJMs and provides valuable guidance for their design,optimization,and industrial application.

关键词： Multi-orifice cross-flow jet mixer Micromixing performance Finite-rate/modified eddy dissipation model Computational fluid dynamics Villermaux/Dushman reaction

Chinese Society of Cardiology guidelines on the diagnosis and treatment of adult fulminant myocarditis

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Science China(Life Sciences) 2024年第5期67卷 913-939页

作者： Chinese Society of Cardiology,Chinese Medical Association,Writing Group Jiangang Jiang Hongyang Shu Dao Wen Wang Rutai Hui Chenze Li Xiao Ran Hong Wang Jing Zhang Shaoping Nie Guanglin Cui Dingcheng Xiang Qun Shao Shengyong Xu Discussion experts:Ning Zhou Yuming Li Wei Gao Yuguo Chen Yuan Bian Guoping Wang Liming Xia Yan Wang Chunxia Zhao Zhiren Zhang Yuhua Zhao Jianan Wang Shaoliang Chen Hong Jiang Jing Chen Xianjin Du mao Chen Yinxian Sun Sheng Li Hu Ding Xueping ma Hesong Zeng Li Lin Shenghua Zhou likun ma Ling Tao Juan Chen Yiwu Zhou Xiaomei Guo 不详 Tongji Hospital Tongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China Fuwai Hospital National Center for Cardiovascular DiseasesChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100037China Zhongnan Hospital of Wuhan University Wuhan 430062China Fuwai Huazhong Cardiovascular Hospital Zhengzhou 450003China Beijing Anzhen Hospital Capital Medical UniversityBeijing 100029China Guangzhou General Hospital of Guangzhou Military Command Guangzhou 510010China Harbin Medical University Cancer Hospital Harbin 150081China Union Hospital Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100730China Taida Hospital Tianjin 300457China Peking University Third Hospital Beijing 100191China Qilu Hospital of Shandong University Jinan 250012China Kanghua Hospital DongguanGuangzhou 523080China Second Affiliated Hospital Zhejiang University School of Medicine Hangzhou 310003China Nanjing First Hospital Nanjing Medical UniversityNanjing 210006China Renmin Hospital of Wuhan University Wuhan 430060Wuhan West China Hospital Sichuan UniversityChengdu 610044China First Hospital of China Medical University Shenyang 110002China General Hospital of Ningxia Medical University Yinchuan 750003China The Second Xiangya Hospital Central South UniversityChangsha 410012China The First Affiliated Hospital of USTC University of Science and Technology of ChinaHefei 230002China The First Affiliated Hospital of Air Force Medical University Xi’an 710032China Central Hospital of Wuhan City Wuhan 430014China Tongji Medical College Huazhong University of Science and TechnologyWuhan 430030China

Fulminant myocarditis is an acute diffuse inflammatory disease of *** is characterized by acute onset,rapid progress and high risk of *** pathogenesis involves excessive immune activation of the innate immune system and formation of inflammatory *** to China’s practical experience,the adoption of the“life support-based comprehensive treatment regimen”(with mechanical circulation support and immunomodulation therapy as the core)can significantly improve the survival rate and long-term *** emphasis is placed on very early identification,very early diagnosis,very early prediction and very early treatment.

关键词： fulminant myocarditis guidelines life support-based comprehensive treatment regimen diagnosis treatment cytokine storm overactivation of immunity

LES of the Sandia flame series D-F using the Eulerian stochastic field method coupled with tabulated chemistry

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Chinese Journal of Aeronautics 2020年第1期33卷 116-133页

作者： Yifan DUAN Zhixun XIA likun ma Zhenbing LUO Xu HUANG Xiong DENG College of Aerospace Science and Technology National University of Defense TechnologyChangsha 410073China

In this paper,the Eulerian Stochastic Field(ESF)model in the Transported Probability Density Function(TPDF)class model is combined with the Flamelet Generated manifolds(FGM)*** method solves the joint probability density function transport equation by ESF method that considers the interaction mechanism between flame and turbulence with high *** the same time,by making use of the advantage of the FGM model,this model is able to incorporate the detailed chemical reaction mechanism(GRI 3.0)with acceptable computational *** new model has been implemented in the open source CFD suite-Open *** of the model has been carried out by simulating the Sandia flame series(three turbulent piloted methane jet flames)issued by the National Laboratory of the United *** accuracy and advancement of the ESF/FGM turbulent combustion model are verified by comparing the LES results of the new model with the rich experimental data as well as the RANS *** results demonstrate that the model has a strong ability in capturing combustion phenomena such as extinction and re-ignition in turbulent flame,which is essential in the accurate prediction of the combustion process in real combustion devices,for example,aircraft engines.

关键词： Eulerian Stochastic Field(ESF) Flamelet Generated manifolds(FGM) Large Eddy Simulation(LES) Open FOAM Turbulent combustion

Effect of carbon dioxide concentration on the combustion characteristics of boron agglomerates in oxygen-containing atmospheres

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第11期24卷 949-959页

作者： Lian DUAN Zhixun XIA Yunchao FENG Binbin CHEN Jiarui ZHANG likun ma College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China

In ramjet combustion chambers,carbon dioxide(CO_(2))produced by the combustion of carbonaceous fuel enters the chamber together with boron *** order to investigate the effect of CO_(2)concentration present in an oxygen-containing atmosphere on the combustion characteristics and oxidation mechanisms of boron agglomerates,we used a laser ignition system,an X-ray diffractometer(XRD),and a thermogravimetric-differential scanning calorimetry(TG-DSC)combined thermal analysis ***-particle boron was tested in the laser-ignition experiments as the control *** ignition experiment results showed that with a fixed O2 concentration of 20%,when the particle temperature reaches the melting point of boron,increasing CO_(2)content causes the combustion process of boron agglomerates to transition from single-particle molten droplet combustion to porous-particle ***,XRD analysis results indicated that the condensed-phase combustion products(CCPs)of boron particles in a mixed atmosphere of O2 and CO_(2)contained B4C,which is responsible for the porous structure of the *** temperatures below 1200℃,the addition of CO_(2)has no obvious promotion effect on boron exothermic ***,in the laser-ignition experiment,when the oxygen concentration was fixed at 20%while the CO_(2)concentration increased from 0%to 80%,the maximum temperature of boron agglomerates rose from 2434 to 2573 K,the self-sustaining combustion time of single-particle boron decreased from 396 to 169 ms,and the self-sustaining combustion time of boron agglomerates decreased from 198 to 40 *** study conclusively showed that adding CO_(2)to an oxygen-containing atmosphere facilitates boron reaction and consumption pathways,which is beneficial to promoting exothermic reaction of boron agglomerates at relatively high temperatures.

关键词： Boron combustion Amorphous boron Boron-containing propellant Solid fuel ramjet

Research progress on solid-fueled Scramjet

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Chinese Journal of Aeronautics 2022年第1期35卷 398-415页

作者： Xiang ZHAO Zhixun XIA likun ma Chaolong LI Chuanbo FANG Benveniste NATAN Alon GANY Department of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China Qinghe Building Ding-3 Beijing 100085China Faculty of Aerospace Engineering Technion-Israel Institute of TechnologyHaifa 32000Israel

The solid-fueled Scramjet is an interesting option for supersonic combustion *** shows significant advantages such as simple fuel supply and compactness,avoiding the complex system of tanks and pipelines that encountered in liquid-fueled *** solid-fueled Scramjet could be the simplest air-breathing engine for the hypersonic flight *** paper presents a comprehensive and systematic review of the research progress on solid-fueled Scramjet in various institutes and *** summarizes a progress overview of three types of the solid-fueled Scramjet,which covers a wealth of landmark numerical and experimental *** on this,several relevant key technologies are *** inherent scientific issues are refined,such as the mixing mechanism of multi-phase flow and supersonic airflow,ignition and combustion mechanism of the condensed phase in a supersonic airflow,and coupling mechanism of gas and solid phase in a supersonic ***,the historical development trend is clarified,and some recommendations are provided for future solid-fueled Scramjet.

关键词： Combustor performance Flame stabilization Self-ignition Solid-fueled Scramjet Supersonic combustion ramjet

凹腔构型对超声速气-固两相富燃燃气掺混燃烧的影响

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固体火箭技术 2024年第5期47卷 620-628页

作者：马立坤杨鹏年夏智勋冯运超赵李北刘延东国防科技大学高超声速技术实验室长沙410073

凹腔作为燃烧增强装置,在超声速气-固两相富燃燃气掺混燃烧中发挥着重要作用。基于火焰稳定凹腔和斜劈装置,提出了波瓣凹腔构型,通过数值模拟深入分析了凹腔构型在超声速气流中对气-固两相富燃燃气掺混燃烧的影响。通过对流场参数、流... 详细信息

凹腔作为燃烧增强装置,在超声速气-固两相富燃燃气掺混燃烧中发挥着重要作用。基于火焰稳定凹腔和斜劈装置,提出了波瓣凹腔构型,通过数值模拟深入分析了凹腔构型在超声速气流中对气-固两相富燃燃气掺混燃烧的影响。通过对流场参数、流场云图及颗粒运动轨迹等的分析,发现富燃燃气中的气相组分和凝相颗粒在空间分布和释能过程中表现出分区运动和分区燃烧的特点。结果表明:随着燃烧过程的深入,颗粒的空间分布逐渐分散;流场参数在燃气喷口附近变化剧烈、流场下游变化缓慢;波瓣结构具备增强流场湍动能和降低流场不均匀性的能力,进而促进了各组分的掺混燃烧;采用双波瓣凹腔时展现出最优的促进效果。波瓣结构能够扩大流场中高温区域的空间分布,有效延长凝相颗粒在高温区域的停留时间,为凝相颗粒的燃烧和能量释放提供了更为有利的条件。

关键词：超声速气流气-固两相波瓣型凹腔掺混燃烧数值模拟

Detailed modeling of aluminum particle combustion——From single particles to cloud combustion in Bunsen flames

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Chinese Journal of Aeronautics 2022年第5期35卷 319-332页

作者： Jiarui ZHANG Oliver T.STEIN Tien D.LUU Ali SHAMOONI Zhixun XIA Zhenbing LUO likun ma Yunchao FENG Andreas KRONENBURG College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China Institut für Technische Verbrennung Universitat StuttgartStuttgart 70174Germany

A numerical model for aluminum cloud combustion which includes the effects of interphase heat transfer,phase change,heterogeneous surface reactions,homogeneous combustion,oxide cap growth and radiation within the Euler–Lagrange framework is *** model is validated in single particle configurations with varying particle *** combustion process of a single aluminum particle is analyzed in detail and the particle consumption rates as well as the heat release rates due to the various physical/chemical sub-models are *** combustion time of single aluminum particles predicted by the model are in very good agreement with empirical correlations for particles with diameters larger than 10μ*** prediction error for smaller particles is noticeably reduced when using a heat transfer model that is capable of capturing the transition regime between continuum mechanics and molecular *** predictive capabilities of the proposed model framework are further evaluated by simulating the aluminum/air Bunsen flames of Mc Gill University for the first *** show that the predicted temperature distribution of the flame is consistent with the experimental data and the double-front structure of the Bunsen flame is reproduced *** burning rates of aluminum in both single particle and particle cloud configurations are calculated and compared with empirical *** show that the burning rates obtained from the present model are more reasonable,while the correlations,when embedded in the Euler–Lagrange context,tend to underestimate the burning rate in the combustion stage,particularly for the considered fuel-rich flames.

关键词： Aluminum particle combustion Bunsen flame Burning time Burning rate Particle cloud

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汽车驾驶模拟器在交通安全中的应用研究

时代汽车 2024年第15期 181-183页

作者：李开英岑少飞马力琨林国王米国支广西城市职业大学广西崇左532100

近年来,交通事故频发,造成了巨大的社会经济损失和人员伤亡,提升交通安全成为当务之急。汽车驾驶模拟器作为一种高科技培训工具,因其可以模拟各种驾驶环境和交通状况,被广泛应用于驾驶技能培训和交通安全教育中。通过模拟真实驾驶场景,... 详细信息

近年来,交通事故频发,造成了巨大的社会经济损失和人员伤亡,提升交通安全成为当务之急。汽车驾驶模拟器作为一种高科技培训工具,因其可以模拟各种驾驶环境和交通状况,被广泛应用于驾驶技能培训和交通安全教育中。通过模拟真实驾驶场景,驾驶员可以在安全可控的环境中学习和掌握各种驾驶技巧,提高应对复杂交通状况的能力,有效减少交通事故的发生。因此,研究汽车驾驶模拟器在交通安全中的应用,具有重要的现实意义和广阔的应用前景。

关键词：汽车驾驶模拟器交通安全

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Effect of electrolyte cation-mediated mechanism on electrocatalytic carbon dioxide reduction

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Chinese Chemical Letters 2024年第7期35卷 139-146页

作者： Yuan Dong Mutian ma Zhenyang Jiao Sheng Han likun Xiong Zhao Deng Yang Peng Soochow Institute of Energy and material Innovations College of EnergyJiangsu Key Laboratory of Advanced Carbon Materials and Wearable Energy TechnologiesSoochow UniversitySoochow 215006China Jiangsu Key Laboratory of Advanced Negative Carbon Technologies Soochow UniversitySoochow 215123China School of Chemistry and Chemical Engineering Shihezi UniversityShihezi 832003China School of Chemical and Environmental Engineering Shanghai Institute of TechnologyShanghai 201418China

The steep reduction in costs and systematic optimization of renewable electricity has ignited an intensifying interest in harnessing electroreduction of carbon dioxide(CO_(2)RR)for the generation of chemicals and *** focus of research over the past few decades has been on the optimization of the electrode and the electrolyte ***,cation species in the latter have recently been found to dramatically alter the selectivity of CO_(2)RR and even their catalytic activity by multiple orders of *** a result,the selection of cations is a critical factor in designing catalytic interfaces with high selectivity and efficiency for targeted *** decision-making regarding cation selection relies on a comprehensive understanding of prevailing electrolyte effect models that have been used to elucidate observed experimental *** this perspective,we review the hypotheses that explain how electrolyte cations influence CO_(2)RR by mechanisms such as through tuning of the interfacial electric field,buffering of the local pH,stabilization of the key intermediates and regulation of the interfacial *** endeavor is to elucidate the molecular mechanisms underpinning cation effects,thus fostering the evolution of more holistic and universally applicable predictive *** this regard,we highlight the current challenges in this area of research,while also identifying potential avenues for future investigations.

关键词： CO_(2)electrocatalytic reduction Cation effects Catalytic mechanisms Catalytic interfaces Electric double layer