检索结果-南通市图书馆

Effect of Heat Flux Distribution on Entropy Generation and Irreversibility of Lead-Bismuth Eutectic(LBE)Forced Convective Heat Transfer

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Thermal Science 2023年第1期32卷 223-236页

作者： zhang Dong zhang haochun WANG Qi SUN Wenbo School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China

Investigations on entropy generation and thermal irreversibility analysis are conducted for liquid lead-bismuth eutectic(LBE)in an annular *** find better performance in convective heat transfer,the computational fluid dynamics(CFD)code based on the finite volume method(FVM)is adopted to solve this *** elevated temperature LBE flows in the annular pipe,and four types of heat flux,including constant,linear increase and decrease,and parabolic distributions are imposed at the inside wall of the annular *** investigations are conducted for the specific average heat input of 200 kW/m^(2),and the different Peclet number Pe is set from 1200 to *** SST k-ωturbulent model and Cheng-Tak Prt model are *** mesh independence validation and models verification are also conducted and the maximum Nu error is 5.43%compared with previous experimental *** results from the local and system scales,respectively,including volumetric dimensionless entropy generation,Ns,Be,and Ep,are *** results indicate that the viscous friction and heat transfer caused by entropy generation can be found in the viscous sub-layer and buffer layer *** transfer is the primary factor that leads to irreversible ***,the results show that the best thermodynamic performance occurs under parabolic distributed heat flux in the research scope.

关键词： liquid lead-bismuth eutectic entropy generation analysis annular pipe CFD

Spatial discretization error in an artificial benchmark model of oblique laser incidence by finite volume approximation for radiative heat transfer

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2012年第16期57卷 2046-2050页

作者： zhang haochun LI Yao School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China Institute of Composite Materials Harbin Institute of TechnologyHarbin 150001China

The spatial discretization error in a finite volume method approximation for radiative heat transfer is investigated. An artificial benchmark model for oblique laser incidence on a two-dimensional rectangle containing a semi-transparent medium is proposed, in addition to using reference data from the Monte Carlo method. Within the framework of the current model, it is shown that numerical scattering in the finite volume method is affected by the spatial grid values and the different spatial discretization schemes to a large degree. Numerical scattering also varies with the degree of absorption coefficient deviation. Numerical scattering is distributed in a symmetrical profile along the laser incidence direction, and all of the schemes show symmetrical cross-scattering.

关键词：有限体积法入射方向模型空间辐射传热基准模型离散误差激光人工

PLD Preparation of GeS_6 Amorphous Film and Investigation on Its Photo-induced Darkening Phenomenon

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2014年第4期29卷 665-668页

作者：刘刚顾少轩 zhang haochun zhang Ning TAO Haizheng School of Electronic Information Wuhan University State Key Laboratory of Silicate Materials for Architectures(Wuhan University of Technology)

GeS6 chalcogenide amorphous fi lm was deposited on glass substrate via PLD（pulsed laser deposition） technique. The performance and structure of the fi lm was characterized by XRD（X-ray diffraction）, SEM（Scanning Electron Microscopy）, EDS（Energy Dispersive Spectroscopy）, optical transmission spectra, and Raman spectra, etc. The GeS6 amorphous fi lm was irradiated by 532 nm linearly polarized light, and its photoinduced darkening was investigated. The results showed that the GeS6 chalcogenide amorphous fi lm was smooth and compact with uniform thickness and combined with the substrate fi rmly, and its chemical composition was in consistency with the bulky target. When laser energy was fi xed, the transparence of the fi lm declined with the increase of the laser irradiation time. Obvious photo-induced darkening and relaxation phenomenon of the fi lm after laser irradiation were observed in this investigation.

关键词： GeS_6 chalcogenide amorphous film pulsed laser deposition photo darkening

Application of entropy production theory to hydro-turbine hydraulic analysis

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2013年第7期56卷 1636-1643页

作者： GONG RuZhi WANG HongJie CHEN LiXia LI DeYou zhang haochun WEI XianZhu School of Energy Science and Engineering Harbin Institute of Technology Hydraulic Research Department of Hydro Turbine Harbin Institute of Large Electrical Machinery

The understanding of hydraulic behavior in the hydro turbine requires the detailed study of fluid flow in the turbine. Previous methods of analyzing the numerical simulation results on the fluid machinery are short of intuitiveness on energy *** this paper, the energy dissipation was analyzed based on the entropy production theory. 3-D steady flow simulations and entropy production calculations of the reduced hydro turbine were carried out. The results indicated that the entropy production theory was suitable for evaluating the performance of the hydro turbine. The energy dissipation in the guide vanes area weighted nearly 25% of the whole flow passage, and mainly happened at the head and tail areas of the vanes. However, more than half the energy dissipation occurred in the runner, mostly at the leading edge of runner blade and the trailing edge of run-ner blade. Meanwhile, close to 20% of the energy dissipation occurred in the elbow. And it can be concluded that the method of entropy production analysis has the advantages of determining the quantity of energy dissipation and where the dissipation happens.

关键词： fluid machinery hydro turbine entropy production energy dissipation

Thermal conductivity of micro/nano-porous polymers: Prediction models and applications

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2022年第2期17卷 135-153页

作者： Haiyan Yu haochun zhang Jinchuan Zhao Jing Liu Xinlin Xia Xiaohu Wu School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China Microcellular Plastics Manufacturing Laboratory(MPML) Department of Mechanical&Industrial EngineeringUniversity of Toronto5 King’s College RoadTorontoM5S 3G8OntarioCanada Cellular Polymer Science&Technology Laboratory School of Materials Science&EngineeringShandong UniversityJinan 250061China Shandong Institute of Advanced Technology Jinan 250100China

Micro/nano-porous polymeric material is considered a unique industrial material due to its extremelylow thermal conductivity, low density, and high surface area. Therefore, it is necessary to establishan accurate thermal conductivity prediction model suiting their applicable conditions and provide atheoretical basis for expanding their applications. In this work, the development of the calculationmodel of equivalent thermal conductivity of micro/nano-porous polymeric materials in recent yearsis summarized. Firstly, it reviews the process of establishing the overall equivalent thermal conductivity calculation model for micro/nanoporous polymers. Then, the predicted calculation models ofthermal conductivity are introduced separately according to the conductive and radiative thermalconductivity models. In addition, the thermal conduction part is divided into the gaseous thermalconductivity model, solid thermal conductivity model and gas-solid coupling model. Finally, it isconcluded that, compared with other porous materials, there are few studies on heat transfer of micro/nanoporous polymers, especially on the particular heat transfer mechanisms such as scale effectsat the micro/nanoscale. In particular, the following aspects of porous polymers still need to be furtherstudied: micro scaled thermal radiation, heat transfer characteristics of particular morphologies at thenanoscales, heat transfer mechanism and impact factors of micro/nanoporous polymers. Such studieswould provide a more accurate prediction of thermal conductivity and a broader application in energyconversion and storage systems.

关键词： thermal conductivity micro/nanoscale thermal radiation micro/nanoscale thermal conduction porous polymers heat transfer properties

2D/2D step-schemeα-Fe2O3/Bi2WO6 photocatalyst with efficient charge transfer for enhanced photo-Fenton catalytic activity

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Catalysis 2021年第1期42卷 97-106页

作者： Wenliang Wang Wenli Zhao haochun zhang Xincheng Dou Haifeng Shi School of Science Jiangnan UniversityWuxi 214122 JiangsuChina Jiangsu Provincial Research Center of Light Industrial Optoelectronic Engineering and Technology Jiangnan UniversityWuxi 214122JiangsuChina

Although the traditional Fenton reaction is considered an effective strategy for solving problems caused by environmental pollution,construction of an efficient photocatalytic system by coordinating the Fenton reaction is *** this study,2D/2D step-schemeα-Fe2O3/Bi2WO6(FO/BWO)heterostructure photo-Fenton catalysts were successfully fabricated by a facile hydrothermal *** as-prepared materials were characterized by XRD,FT-IR,TEM,XPS,UV-vis DRS,PL,I-t,EIS,and BET *** visible light irradiation,FO/BWO exhibited remarkably high and stable photo-Fenton catalytic activity for the degradation of methyl blue(MB)at low concentrations of *** was noted that FO/BWO(0.5)displayed a significantly enhanced photo-Fenton catalytic activity,which was 11.06 and 3.29 times those of FO nanosheets and BWO nanosheets,*** notably improved photo-Fenton catalytic activity of FO/BWO was mainly due to the combination of H2O2 and FO under light illumination and the presence of the 2D/2D S-scheme heterostructure,with the large contact surface,abundant active sites,and efficient separation rate of photogenerated carriers playing contributory ***,a possible catalytic mechanism for the FO/BWO composite was preliminarily proposed via active species trapping *** summary,this study provided new insights into the synthesis of an effectively heterogeneous 2D/2D S-scheme photo-Fenton catalyst for degradation of organic pollutants in wastewater.

关键词： Bi2WO6 α-Fe2O3 S-scheme Photo-Fenton 2D photocatalyst

在线全文

学校读者我要写书评

暂无评论

极近距离煤层群多工作面协调开采规划研究

煤炭工程 2023年第12期55卷 34-38页

作者：张浩春山西省晋神能源有限公司山西忻州036500

针对西部矿井浅埋煤层群多工作面协调开采难题,以山西河曲沙坪煤矿为工程背景,采用理论分析、数值模拟的研究方法,对于二盘区内多煤层工作面开采的时序和空间布局进行了分析和优化,有效指导了二盘区内的工作面布置和接续。结果表明:通... 详细信息

针对西部矿井浅埋煤层群多工作面协调开采难题,以山西河曲沙坪煤矿为工程背景,采用理论分析、数值模拟的研究方法,对于二盘区内多煤层工作面开采的时序和空间布局进行了分析和优化,有效指导了二盘区内的工作面布置和接续。结果表明:通过数值模拟分析实现了不同开采方案的采动响应定量化分析,重复采动的覆岩结构决定着侧向采动影响角;13104工作面需在9201和9202工作面开采后接续,对10201无明显影响;协调开采时为保障综放工作面顺序接替,需采用切顶卸压沿空掘巷技术。

关键词：煤层群协调开采盘区尺度遗留煤柱沿空留巷

二维MOC Krylov子空间迭代的CMFD预条件子研究

在线全文

学校读者我要写书评

暂无评论

核动力工程 2023年第S2期44卷 120-125页

作者：张广春张昊春哈尔滨工业大学能源科学与工程学院哈尔滨100051

为了提高二维特征线(MOC)Krylov子空间迭代的效率,提出了基于粗网有限差分(CMFD)矩阵的预条件子。研究首先将CMFD加速方法进行线性化,推导出线性CMFD预条件子;其次将线性CMFD预处理Krylov子空间方法用于求解二维MOC方程;最后利用IAEA LW... 详细信息

为了提高二维特征线(MOC)Krylov子空间迭代的效率,提出了基于粗网有限差分(CMFD)矩阵的预条件子。研究首先将CMFD加速方法进行线性化,推导出线性CMFD预条件子;其次将线性CMFD预处理Krylov子空间方法用于求解二维MOC方程;最后利用IAEA LWR和2D C5G7基准题对线性CMFD预条件子的加速性能进行了测试。结果表明:在应用CMFD预条件子后,IAEA LWR基准题的迭代次数减少了52.7%,计算时间减少了41.8%;2-D C5G7基准题的迭代次数减少了20.3%,计算时间减少了13.2%;研究还发现CMFD预条件子对于局部非均匀性不强的问题效果很好,对于局部非均匀性较强的问题性能下降。

关键词：特征线方法(MOC) Krylov子空间迭代粗网有限差分(CMFD) 预条件子

在线全文

学校读者我要写书评

暂无评论

核动力航天器管壳式换热器换热特性分析

哈尔滨工程大学学报 2023年第12期44卷 2185-2191页

作者：李增恩张昊春赵姝婷张诚哈尔滨工业大学能源科学与工程学院黑龙江哈尔滨150001

为了研究核动力航天器所需碱金属管壳式换热器的换热特性,本文设计一种换热结构,通过流固耦合传热方法对该换热结构的换热和流动特性进行仿真分析,研究了不同冷、热流体管道布置方式下的换热特性。利用结构化和非结构化网格的网格组装方... 详细信息

为了研究核动力航天器所需碱金属管壳式换热器的换热特性,本文设计一种换热结构,通过流固耦合传热方法对该换热结构的换热和流动特性进行仿真分析,研究了不同冷、热流体管道布置方式下的换热特性。利用结构化和非结构化网格的网格组装方法,实现不同流体域的耦合换热。对K、Na和NaK流体通道进行对比分析,得出当换热器功率为兆瓦级时,适合选择Na工质作为冷却剂。对流体管道进行优化设计,得出在不改变冷、热流体换热空间体积的情况下,优化设计后的管道布置结构换热能力更强。研究表明当低温流体速度较慢且高温流体速度较快时,冷却效率更高。本文可为核动力航天器的换热器设计和开发提供参考依据。

关键词：空间核动力管壳式换热器碱金属工质 Cheng Tak模型仿真分析耦合换热优化设计湍动能分析

维普期刊数据库博看期刊