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Comprehensive evaluations of heat transfer performance with conjugate heat dissipation effect in high-speed rotating free-disk modeling of aero-engines

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Fundamental Research 2024年第3期4卷 611-623页

作者： Aqiang Lin Gaowen Liu Ran Chang Yan Chen Qing Feng School of Power and Energy Northwestern Polytechnical UniversityXi'an 710129China Shaanxi Key Laboratory of thermal Science in Aero-engine System Northwestern Polytechnical UniversityXi'an 710072China Research&Development Institute of Northwester

thermal boundary conditions of the turbine disk cavity system are of great importance in the design of secondary air systems in *** study aims to investigate the complex heat transfer mechanisms of a rotating turbine disk under high-speed conditions.A high-speed rotating free-disk model with Dorfman empirical solutions is developed to evaluate the heat transfer performance considering various ***,the influence of compressibility,variable properties,and heat dissipation is determined using theoretical and numerical *** particular,a novel combined solution method is proposed to simplify the complex heat transfer *** results indicate that the heat transfer performance of a free disk is primarily influenced by the rotating Mach number,rotating Reynolds number,Rossby number,and wall temperature *** heat transfer temperature and Nusselt number of the free disk are strongly correlated with the rotating Mach number and rotating Reynolds *** reveals that heat dissipation is a critical factor affecting the accurate evaluation of the heat transfer performance of the turbine ***,the combined solution method can serve as a reference for future investigations of flow and heat transfer in high-speed rotating turbine disk cavity systems in aero-engines.

关键词： Aero-engine Rotating turbine disk Dimensional analysis Compressibility Heat dissipation Dorfman empirical solution

Insight into the mechanism of 5-hydroxymethylfurfural electroreduction to 2,5-bis(hydroxymethyl)furan over Cu anchored N-doped carbon nanosheets

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Nano Research 2024年第9期17卷 7991-7999页

作者： Haoran Wu Xinwei Chen Haishan Xu Runlu Yang Xin Wang Junying Chen Zhenbing Xie Liang Wu Yiyong Mai School of Chemical Engineering Zhengzhou UniversityZhengzhou 450001China School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative MoleculesShanghai Key Laboratory of Electrical Insulation and Thermal AgeingShanghai Jiao Tong UniversityShanghai 200240China Department of Chemistry Tangshan Normal UniversityTangshan 063000China

Design of non-noble metal electrocatalysts for biomass conversion to high-value chemicals and understanding the related catalytic mechanisms are of profound significance but have remained a major ***,we developed a novel biomass-derived electrocatalyst(denoted as Cu/NC),featuring with electron-deficient copper nanoparticles anchored on N-doped carbon nanosheets,for the electrochemical reduction of 5-hydroxymethylfurfural(HMF)to 2,5-bis(hydroxymethyl)furan(BHMF,a vital precursor of functional polymers).The optimized Cu/NC electrocatalyst exhibited an excellent performance with high Faradaic efficiency(89.5%)and selectivity(90.8%)of BHMF at a low concentration of HMF(18.1 mM).Even at a very high HMF concentration(108.6 mM),the Faraday efficiency and selectivity of BHMF could still reach 74.8%and 81.1%,*** performance approached those of the reported noble metal-based *** study revealed that the N doping in the Cu/NC catalyst could regulate the electronic structure of Cu,strengthening the adsorption of the HMF carbonyl group,and thus boosting the selectivity of ***,strong electronic metal-support interactions of Cu and the N-doped carbon support optimized the charge transfer rate,thus promoting the dissociation of water to the active hydrogen(H^(*))species and boosting the reaction kinetic rate of H^(*)and HMF.

关键词： biomass 5-hydroxymethylfurfural electrochemical reduction N-doped carbon materials 2,5-bis(hydroxymethyl)furan

Microstructure and Shear Properties Evolution of Minor Fe-Doped SAC/Cu Substrate Solder Joint under Isothermal Aging

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Acta Metallurgica Sinica(English Letters) 2024年第7期37卷 1279-1290页

作者： Quanzhen Li Chengming Li Xiaojing Wang Shanshan Cai Jubo Peng Shujin Chen Jiajun Wang Xiaohong Yuan Jiangsu University of Science and Technology Zhenjiang212003China R&D Center Yunnan Tin Group(Holding)Co.LtdKunming650000China The 58 Research Institute of China Electronics Technology Group CorporationWuxi214100China Yunnan Precious Metals Lab Sino-Platinum Metals Co.LtdKunming650156China

Different amounts of Fe(0.005,0.01,0.03,0.05,and 0.07 wt%)were added to SAC305 to study the shear behavior damage of Fe-doped SAC solder joints under thermal loading(170℃,holding time of 0,250,500,and 750 h).The results show that during isothermal aging at 170℃,the average shear force of all solder joints decreases with increasing aging time,while the average fracture energy first increases and then decreases,reaching a maximum at 500 *** Fe doping could both increase shear forces and related fracture energy,with the optimum Fe doping amount being 0.03 wt%within the entire aging *** is because the doping Fe reduces the undercooling of the SAC305 alloy,resulting in the microstructure refining of solder *** in turn causes the microstructure changing from network structure(SAC305 joint:eutectic network+β-Sn)to a single matrix structure(0.03Fe-doped SAC305 joint:β-Sn matrix+small compound particles).Specifically,Fe atoms can replace some Cu in Cu_(6)Sn_(5)(both inside the solder joint and at the interface),and then form(Cu,Fe)_(6)Sn_(5) compounds,resulting in an increase in the elastic modulus and nanohardness of the ***,the growth of Cu_(6)Sn_(5) and Cu_(3)Sn intermetallic compounds(IMC)layer are inhibited by Fe doping even after the aging time prolonging,and Fe aggregates near the interface compound to form FeSn_(2).This study is of great significance for controlling the growth of interfacial compounds,stabilizing the microstructures,and providing strengthening strategy for solder joint alloy design.

关键词： SAC305 solder Fe doping Shear mechanical behavior Isothermal aging Interfacial intermetallic compounds(IMC)

New Hybrid CHP System Integrating Solar Energy and Exhaust Heat Thermochemical Synergistic Conversion with Dual-Source Energy Storage

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Journal of thermal Science 2024年第3期33卷 970-984页

作者： QIN Yuanlong LIU Taixiu LI Peijing ZHAO Kai JIAO Fan PEI Gang LIU Qibin Department of thermal Science and Energy Engineering University of Science and Technology of ChinaHefei230027China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China School of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing102206China

For the efficient use of solar and fuels and to improve the supply-demand matching performance in combined heat and power(CHP)systems,this paper proposes a hybrid solar/methanol energy system integrating solar/exhaust thermochemical and thermal energy *** proposed system includes parabolic trough solar collectors(PTSC),a thermochemical reactor,an internal combustion engine(ICE),and hybrid storage of thermal and chemical energy,which uses solar energy and methanol fuel as input and outputs power and *** methanol thermochemical decomposition reaction,mid-and-low temperature solar heat and exhaust heat are upgraded to chemical energy for efficient power *** thermal energy storage(TES)stores surplus thermal energy,acting as a backup source to produce heat without emitting CO_(2).Due to the energy storage,time-varying solar energy can be used steadily and efficiently;considerable supply-demand mismatches can be avoided,and the operational flexibility is *** the design condition,the overall energy efficiency,exergy efficiency,and net solar-to-electric efficiency achieve 72.09%,37.65%,and 24.63%,*** fuel saving rate(FSR)and the CO_(2) emission reduction(ER_(CO_(2)))achieve 32.97%and 25.33%,*** research findings provide a promising approach for the efficient and flexible use of solar energy and fuels for combined heat and power.

关键词： hybrid energy system solar thermochemical exhaust heat energy storage operational flexibility

Exerkine response to acute exercise:Still much to discover

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Journal of Sport and Health Science 2024年第6期13卷 759-760页

作者： Pedro L.Valenzuela Beatriz Rivas-Baeza Carmen Fiuza-Luces Alejandro Lucia Physical Activity and Health Research group(“PaHerg”) Research Institute of Hospital“12 de Octubre”(“imas12”)Madrid 28041Spain Department of systems Biology University of AlcalaMadrid 28871Spain Centro de Salud Luis Vives Alcala de HenaresMadrid 28803Spain Faculty of Sport Sciences Universidad Europea de MadridMadrid 28670Spain

Strong evidence supports the benefits of regular physical activity/exercise for the prevention and management of numerous non-communicable diseases.^(1,2)However,despite important advances(particularly the implementation of complex“omics”approaches),the underlying molecular mechanisms remain to be clearly *** the past decade,the role of exerkines—a myriad of signaling moieties(e.g.,mainly cytokines but also other small peptides,peptides,nucleic acids,lipids,or metabolites,among others)released by muscles(myokines)and other tissues in response to exercise that induces endocrine(at the multisystem level),paracrine,or autocrine effects—has gained attention.^(3,4)Indeed it has been proposed that some of the salutary effects of regular exercise(i.e.,repeated sessions of acute exercise)might be due,at least partly,to the progressive accumulation of frequent,acute episodes of exerkine release.^(5)

关键词： gained multisystem prevention

Influence of Mixture Gas Conditions on the Laminar Combustion Characteristics of Natural Gas

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Journal of thermal Science 2024年第3期33卷 1231-1241页

作者： LOU Diming ZHU Kan ZHANG Yunhua REN Yedi TAN Piqiang FANG Liang FAN Lanlan School of Automotive Studies Tongji UniversityShanghai201804China Ji’nan Power Co.Ltd Sinotruk GroupJi’nan250200China

Natural gas is a promising alternative fuel for the internal combustion engine,and natural gas engine has become an efficient and feasible measure to deal with the energy shortage and climate *** the laminar flame characteristics are the foundation of the turbulent flame,the laminar flame characteristics of natural gas have a significant impact on the combustion status and efficiency of the engine.A visual constant volume bomb was used to study the influence of the gas components,different excess air coefficient(λ),and initial conditions on the laminar combustion characteristics of natural *** experimental results showed that when the initial pressure and temperature were 0.1 MPa and 300 K respectively,compared to propane,ethane had a remarkable influence on the equivalent-combustion laminar-combustion-speed,with an average increase of approximately 5.1%for every 2.5%increase in the ethane *** laminar combustion velocity of the natural gas under different excess air coefficients had a maximum value at aboutλ=1.0,and the Markstein length of the flame decreased with the increase of theλ.The increase in the initial pressure of the mixture resulted in a decrease in the equivalent-combustion laminar-combustion-speed of the flame,a significant decrease in the Markstein *** increase of the initial temperature of the mixture led to a rapid increase of the equivalent-combustion laminar-combustion-speed,but the effect on the flame Markstein length was not dominant.

关键词： constant volume bomb natural gas engine combustion characteristics laminar combustion velocity Markstein length

Performance Evaluation of an Evaporative Cooling Pad for Humidification-Dehumidification Desalination

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Fluid Dynamics & Materials Processing 2024年第10期20卷 2323-2335页

作者： Ibtissam El Aouni Hicham Labrim Elhoussaine Ouabida Ahmed Ait Errouhi Rachid El Bouayadi Driss Zejli Aouatif Saad Advanced systems Engineering Laboratory National School of Applied SciencesIbn Tofail UniversityKenitra14000Morocco

The perfect combination of renewable energy and desalination technologies is the key to meeting water demands in a cost-effective,efficient and environmentally friendly *** desalination technique by humidificationdehumidification is non-conventional approach suitable for areas with low infrastructure(such as rural and decentralized regions)since it does not require permanent *** this study,this technology is implemented by using solar energy as a source of thermal power.A seawater desalination unit is considered,which consists of a chamber with two evaporators(humidifiers),a wetted porous material made of a corrugated cellulose cardboard and a condenser(dehumidifier).The evaporation system is tested with dry bulb temperature and relative air humidity *** results of numerical simulations indicate that higher inlet air velocities(from 0.75 to 3 m/s)lead to a decrease in theΔT,ΔRH,and *** the air remaining within the evaporator for 30 cm,the temperature differential increases to 5.7°C,accompanied by a 39%rise in relative humidity *** changes result in a significant enhancement in humidification efficiency,achieving a remarkable efficiency level of 78%.However,a wettability value of 630 m^(2)/m^(3)leads to a smaller reduction of these *** the pad thickness,particularly to 0.3 m,improves performance by boostingΔT,ΔRH,and effectiveness,especially for pads with a wettability of 630 m^(2)/m^(3),for which superior performances are predicted by the numerical tests.

关键词： Desalination humidification dehumidification porous material solar energy evaporator

Adaptive battery thermal management systems in unsteady thermal application contexts

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Journal of Energy Chemistry 2024年第10期97卷 650-668页

作者： Kailong Liu Qiao Peng Zhuoran Liu Wei Li Naxin Cui Chenghui Zhang School of Control Science and Engineering Shandong University Information Technology Analytics & Operations Group Queen's University Belfast College of Design and Engineering National University of Singapore

With the increasing attention paid to battery technology,the microscopic reaction mechanism and macroscopic heat transfer process of lithium-ion batteries have been further studied and understood from both academic and industrial ***,as one of the key parameters in the physical fra mework of batteries,affects the performa nce of the multi-physical fields within the battery,a nd its effective control is *** the heat generation in the battery is determined by the real-time operating conditions,the battery temperature is essentially controlled by the real-time heat dissipation conditions provided by the battery thermal management *** battery thermal management systems have basic temperature control capabilities for most conventional application ***,with the current development of la rge-scale,integrated,and intelligent battery technology,the adva ncement of battery thermal management technology will pay more attention to the effective control of battery temperature under sophisticated situations,such as high power and widely varied operating *** this context,this paper presents the latest advances and representative research related to battery thermal management ***,starting from battery thermal profile,the mechanism of battery heat generation is discussed in ***,the static characteristics of the traditional battery thermal management system are ***,considering the dynamic requirements of battery heat dissipation under complex operating conditions,the concept of adaptive battery thermal management system is proposed based on specific research ***,the main challenges for battery thermal management system in practice are identified,and potential future developments to overcome these challenges are presented and discussed.

关键词： Battery safety Battery thermal management system Cooling methods Heat generation mechanism Lithium-ion batteries

Sample Generation for Security Region Boundary Identification Based on Topological Features of Historical Operation Data

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Journal of Modern Power systems and Clean Energy 2024年第4期12卷 1087-1095页

作者： Xiaokang Wu Wei Xu Feng Xue College of Energy and Electrical Engineering Hohai UniversityNanjingChina NARI group Corporation NanjingChina State Grid Electric Power Research Institute NanjingChina

Since the scale and uncertainty of the power sys-tem have been rapidly increasing,the computation efficiency of constructing the security region boundary(SRB)has become a prominent *** on the topological features of histori-cal operation data,a sample generation method for SRB identi-fication is proposed to generate evenly distributed samples,which cover dominant security *** boundary sample pair(BSP)composed of a secure sample and an unsecure sam-ple is defined to describe the feature of *** resolution,sampling,and span indices are designed to evaluate the cover-age degree of existing BSPs on the SRB and generate samples closer to the *** on the feature of flat distribution of BSPs over the SRB,the principal component analysis(PCA)is adopted to calculate the tangent vectors and normal vectors of ***,the sample distribution can be expanded along the tangent vector and corrected along the normal vector to cover different security ***,a sample set is randomly gen-erated based on the IEEE standard example and another new sample set is generated by the proposed *** results in-dicate that the new sample set is closer to the SRB and covers different security modes with a small calculation time cost.

关键词： Clustering analysis principal component analysis(PCA) sample generation security region boundary(SRB)