检索结果-南通市图书馆

Effect of cis/trans molecular structures on pyrolysis performance and heat sink of decalin isomers

Frontiers of Chemical Science and Engineering 2024年第1期18卷 51-60页

作者： Qing Liu Kang Xue Tinghao Jia Zhouyang Shen Zehao Han Lun Pan Ji-Jun Zou Xiangwen Zhang Key Laboratory for Green Chemical Technology of the Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Collaborative Innovative Center of Chemical Science and Engineering(Tianjin) Tianjin 300072China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China Zhejiang Institute of Tianjin University Ningbo 315201China

Decalin is considered as an important compound of high-energy-density endothermic fuel,which is an ideal on-board coolant for thermal management of advanced aircraft.However,decalin contains two isomers with a tunable composition,and their effects on the pyrolysis performance,such as the heat sink and coking tendency have not been demonstrated.Herein,we investigated the pyrolysis of decalin isomers,i.e.,cis-decalin,trans-decalin and their mixtures(denoted as mix-decalin),in order to clarify the effects of the cis-/trans-structures on the pyrolysis performance of decalin fuels.The pyrolysis results confirmed that conversion of the tested fuels(600–725℃,4 MPa)decreased in the order cis-decalin>mix-decalin>trans-decalin.Detailed analyses of the pyrolysis products were used to compare the product distributions from cis-decalin,mix-decalin and trans-decalin,and the yields of some typical components(such as cyclohexene,1-methylcyclohexene,benzene and toluene)showed significant differences,which could be ascribed to deeper cracking of cis-decalin.Additionally,the heat sinks and coking tendencies of the decalins decreased in the order cis-decalin>mix-decalin>trans-decalin.This work demonstrates the relationship between the cis/trans structures and the pyrolysis performance of decalin,which provides a better understanding of the structure-activity relationships of endothermic hydrocarbon fuels.

关键词： endothermic fuel decalin pyrolysis heat sink molecular structure

来源：

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

An investigation on topologies of hybrid manifold,impinging-jet nozzle and micro-pin-fin heat sinks

引用

Science China(Technological Sciences) 2024年第4期67卷 1061-1076页

作者： SHI QianLei YAO XiaoLe LIU Qian QIN Le JU Xing XU Chao Key Laboratory of Power Station Energy Transfer Conversion and System of MOE North China Electric Power UniversityBeijing 102206China

The hybrid manifold micro-pin-fin(MMPF)heat sink combined nozzle jets is an option for large-scale integrated circuits(LSI).The demond for uniform and ultra-high heat flux removal by MMPF heat sink has not been adequately investigated.This work aims to solve the problem of fluid organization.The proposed basic tiling topologies,including square,regular hexagon,30°rhombus,and 60°rhombus topologies,provide different organized fluid flows and heat transfer patterns.The present study focuses on comparing these topologies according to independent porous medium parameters,such as nozzle pore size D_(Z),flow pore size D_(X,Y),and porosityε.The results show that the square topology achieves the smallest total thermal resistance R_(tot)value of0.0975×10^(-4)K m^2/W,while the hexagon topology achieved the highest value of COP/?T,which was 2033.9 K^(-1).According to the sensitivity analysis results,the optimal total thermal resistance can be obtained by balancing the influences of nozzle pore size,flow pore size,and porosity.The optimal pressure drop can be obtained by maximizing the porosity.

关键词： heat sink ultra-high heat flux manifold micro-pin-fin impinging-jet topology

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Flow and thermal modeling of liquid metal in expanded microchannel heat sink

引用

Frontiers in Energy 2023年第6期17卷 796-810页

作者： Mingkuan ZHANG Xudong ZHANG Luna GUO Xuan LI Wei RAO Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical EngineeringTianjin University of TechnologyTianjin 300384China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of TechnologyTianjin 300384China Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education Department of Engineering MechanicsTsinghua UniversityBeijing 100084China School of Mechanical Engineering Tianjin University of CommerceTianjin 300134China Institute of Refrigeration and Cryogenics Shanghai Jiao Tong UniversityShanghai 200240China Beijing Key Laboratory of CryoBiomedical Engineering and Key Laboratory of Cryogenics Beijing 100190China

Liquid metal-based microchannel heat sinks (MCHSs) suffer from the low heat capacity of coolant, resulting in an excessive temperature rise of coolant and heat sink when dealing with high-power heat dissipation. In this paper, it was found that expanded space at the top of fins could distribute the heat inside microchannels, reducing the temperature rise of coolant and heat sink. The orthogonal experiments revealed that expanding the top space of channels yielded similar temperature reductions to changing the channel width. The flow and thermal modeling of expanded microchannel heat sink (E-MCHS) were analyzed by both using the 3-dimensional (3D) numerical simulation and the 1-dimensional (1D) thermal resistance model. The fin efficiency of E-MCHS was derived to improve the accuracy of the 1D thermal resistance model. The heat conduction of liquid metal in Z direction and the heat convection between the top surface of fins and the liquid metal could reduce the total thermal resistance (Rt). The above process was effective for microchannels with low channel aspect ratio, low mean velocity (Um) or long heat sink length. The maximum thermal resistance reduction in the example of this paper reached 36.0%. The expanded space endowed the heat sink with lower pressure, which might further reduce the pumping power (P). This rule was feasible both when fins were truncated (h_(2) 0).

关键词： liquid metal cooling heat sink expanded microchannel flow and thermal modeling

来源：

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

Theoretic heat sink simulation and experimental investigation of the pyrolysis of substituted cyclohexanes

引用

Journal of Energy Chemistry 2015年第1期24卷 119-125页

作者： Daoan Sun Yongmei Du Chunying Li Jianwei Zhang Juyou Lu Zhixuan Wang Jiaoyi Li Jian L Xi’an Modern Chemistry Research Institute

Reaxgen program for the pyrolysis mechanism of cycloalkanes was adopted to simulate the heat sink of substituted cyclohexanes. Thermal cracking of cyclohexanes was performed to examine the cracking performance, wherein the substituent effects were detailedly discussed under supercritical condition. It was found that Reaxgen program played a good part in the screening and optimization of cyclohexanes. A good agreement with the experimental data for the mono-substituted and bi-substituted cyclohexanes was demonstrated, however, some deviation for the tri-substituted cyclohexanes were observed. The experiment results indicated that the gaseous product yield increased sharply for mono- substituted cyclohexanes with short substituents containing no more than two carbons. Nevertheless, continuous increase in the alkyl chain depressed the gaseous product yield smoothly. The cyclic substituent dramatically inhibited the pyrolysis of cyclohexanes. All the substituents but cyclohexyl had no obvious effect on the yield of hydrogen and olefins （≤C4）. For bi-substituted cyclohexanes, the more close the distance between the two substituents, the higher the gaseous product yield was obtained. However, opposite result on the selectivity to hydrogen and olefins （≤C4） was generally obtained except 1,3-dimethylcyclohexane. The position of tri-substituents acted little significance on the gaseous product yield, as well as the selectivity to hydrogen and olefins （≤C4）.

关键词： reaxgen program pyrolysis heat sink substituted cyclohexanes gaseous product yield selectivity

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Thermal modeling optimization and experimental validation for a single concentrator solar cell system with a heat sink

引用

Chinese Physics B 2013年第8期22卷 456-461页

作者：崔敏陈诺夫邓金祥刘立英 College of Applied Sciences Beijing University of Technology New and Renewable Energy of Beijing Key Laboratory North China Electric Power University

A single concentrator solar cell model with a heat sink is established to simulate the thermal performance of the system by varying the number, height, and thickness of fins, the base thickness and thermal resistance of the thermal conductive adhesive. Influence disciplines of those parameters on temperatures of the solar cell and heat sink are obtained. With optimized number, height and thickness of fins, and the thickness values of base of 8, 1.4 cm, 1.5 mm, and 2 mm, the lowest temperatures of the solar cell and heat sink are 41.7 ~C and 36.3 ~C respectively. A concentrator solar cell prototype with a heat sink fabricated based on the simulation optimized structure is built. Outdoor temperatures of the prototype are tested. Temperatures of the solar cell and heat sink are stabilized with time continuing at about 37 ℃-38 ℃ and 35 ℃-36 ℃respectively, slightly lower than the simulation results because of effects of the wind and cloud. Thus the simulation model enables to predict the thermal performance of the system, and the simulation results can be a reference for designing heat sinks in the field of single concentrator solar cells.

关键词： heat sink concentrator solar cell thermal model cooling

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effects of the porous medium and water-silver biological nanofluid on the performance of a newly designed heat sink by using first and second laws of thermodynamics

引用

Chinese Journal of Chemical Engineering 2020年第11期28卷 2928-2937页

作者： Amin Shahsavar Sajad Entezari Davood Toghraie Pouya Barnoon Department of Mechanical Engineering Kermanshah University of TechnologyKermanshahIran Department of Mechanical Engineering Khomeinishahr BranchIslamic Azad UniversityKhomeinishahrIran

The aim of this numerical investigation is to evaluate the laminar forced convection of biologically synthesized water-silver nanofluid through a heat sink(HS)filled with porous foam(PHS)using first and second laws of thermodynamics.The impacts of inlet velocity(V=0.5–3 m·s^-1)and volume fraction of nanofluid(φ=0–1%)on the performance metrics of HS are assessed and the outcomes are compared with those of the non-porous HS(NHS).The outcomes revealed that for both the PHS and NHS,the increase of V causes an intensification in convection coefficient,pumping power,and entropy generation due to fluid friction,while the maximum CPU temperature,thermal resistance,and entropy generation due to the heat transfer reduces by boosting V.Also,it was found that the augmentation of V results in intensification in convection coefficient,pumping power,overall hydrothermal performance,and frictional entropy generation,while the opposite is true for maximum CPU temperature,thermal resistance,and thermal entropy generation.Furthermore,it was reported that,except forφ=0.5%,the overall hydrothermal performance of NHS is better than that of PHS,while PHS has better second-law performance than NHS in all the studied cases.Also,it can be concluded that the best hydrothermal performance for PHS belongs toφ=1%and V=0.5 m·s^-1,while for NHS,these values are 1%and 2 m·s^-1.

关键词： Porous medium heat sink First and second laws of thermodynamics Biologically prepared water-silver nanofluid

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Computer simulation of Cu:AlOOH/water in a microchannel heat sink using a porous media technique and solved by numerical analysis AGM and FEM

引用

Theoretical & Applied Mechanics Letters 2023年第3期13卷 177-187页

作者： S.A.Abdollahi P.Jalili B.Jalili H.Nourozpour Y.Safari P.Pasha D.D.Ganji Master student-Mechanical Engineering-Energy conversion Faculty of Mechanical EngineeringTabriz UniversityTabrizIran Engineering Faculty of EngineeringNorth Tehran BranchIslamic Azad UniversityTehranIran Department of Mechanical Engineering Noshirvani University of TechnologyBabolIran Department of Mechanical engineering Mazandaran University of science and TechnologyBabolIran

Extensive improvements in small-scale thermal systems in electronic circuits,automotive industries,and microcomputers conduct the study of microsystems as essential.Flow and thermic field characteristics of the coherent nanofluid-guided microchannel heat sink are described in this perusal.The porous media approximate was used to search the heat distribution in the expanded sheet and Cu:γ-AlOOH/water.A hybrid blend of Boehme copper and aluminum nanoparticles is evaluated to have a cooling effect on the microchannel heat sink.By using Akbari Ganji and finite element methods,linear and non-linear differential equations as well as simple dimensionless equations have been analyzed.The purpose of this study is to investigate the fluid and thermal parameters of copper hybrid solution added to water,such as Nusselt number and Darcy number so that we can reach the best cooling of the fluid.Also,by installing a piece of fin on the wall of the heat sink,the coefficient of conductive heat transfer and displacement heat transfer with the surrounding air fluid increases,and the efficiency of the system increases.The overall results show that expanding values on the NP(series heat transfer fluid system maximizes performance with temperatures)volume division of copper,as well as boehmite alumina particles,lead to a decrease within the stream velocity of the Cu:AlOOH/water.Increasing the volume fraction of nanoparticles in the hybrid mixture decreases the temperature of the solid surface and the hybrid nanofluid.The Brownian movement improves as the volume percentage of nanoparticles in the hybrid mixture grows,spreading the heat across the environment.As a result,heat transmission rates rise.As the Darcy number increases,the thermal field for solid sections and Cu:AlOOH/water improves.

关键词： Finite element method AGM method Microchannel heat sink Porous media Cu:γ-AlOOH/water

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Modeling and Simulation of a Hybrid Jet-Impingement/Micro-Channel heat sink

引用

Fluid Dynamics & Materials Processing 2021年第1期17卷 109-121页

作者： Taidong Xu Hao Liu Dejun Zhang Yadong Li Xiaoming Zhou Research Institute of CSIC Nanjing211153China University of Electronic Science and Technology of China Chengdu611731China

With the progressive increase in the number of transistors that can be accommodated on a single integrated circuit,new strategies are needed to extract heat from these devices in an efficient way.In this regard methods based on the combination of the so-called“jet impingement”and“micro-channel”approaches seem extremely promising for possible improvement and future applications in electronics as well as the aerospace and biomedical fields.In this paper,a hybrid heat sink based on these two technologies is analysed in the frame of an integrated model.Dedicated CFD simulation of the coupled flow/temperature fields and orthogonal tests are performed in order to optimize the overall design.The influence of different sets of structural parameters on the cooling performance is examined.It is shown that an optimal scheme exists for which favourable performance can be obtained in terms of hot spot temperature decrease and thermal uniformity improvement.

关键词： Jet impingement micro-channel heat sink numerical simulation orthogonal test

来源：

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

Highly anisotropic thermal conductivity of few-layer CrOCl for efficient heat dissipation in graphene device

引用

Nano Research 2022年第10期15卷 9377-9385页

作者： Xiaoming Zheng Yuehua Wei Zhenhua Wei Wei Luo Xiao Guo Xiangzhe Zhang Jinxin Liu Yangbo Chen Gang Peng Weiwei Cai Shiqiao Qin Han Huang Chuyun Deng Xueao Zhang College of Physical Science and Technology Xiamen UniversityXiamen 361005China College of Advanced Interdisciplinary Studies National University of Defense TechnologyChangsha 410073China College of Arts and Sciences National University of Defense TechnologyChangsha 410073China Hunan Key Laboratory of Super-microstructure and Ultrafast Process School of Physics and ElectronicsCentral South UniversityChangsha 410083China Jiujiang Research Institute of Xiamen University Jiujiang 332105China

With the packing density growing continuously in integrated electronic devices,sufficient heat dissipation becomes a serious challenge.Recently,dielectric materials with high thermal conductivity have brought insight into effective dissipation of waste heat in electronic devices to prevent them from overheating and guarantee the performance stability.Layered CrOCl,an antiferromagnetic insulator with low-symmetry crystal structure and atomic level flatness,might be a promising solution to the thermal challenge.Herein,we have systematically studied the thermal transport of suspended few-layer CrOCl flakes by microRaman thermometry.The CrOCl flakes exhibit high thermal conductivities along zigzag direction,from~392±33 to~1,017±46 W·m^(−1)·K^(−1) with flake thickness from 2 to 50 nm.Besides,pronounced thickness-dependent thermal conductivity ratio(/from~2.8±0.24 to~4.3±0.25)has been observed in the CrOCl flakes,attributed to the discrepancy of phonon dispersion and phonon surface scattering.As a demonstration to the heat sink application of layered CrOCl,we then investigate the energy dissipation in graphene devices on CrOCl,SiO_(2) and hexagonal boron nitride(h-BN)substrates,respectively.The graphene device temperature rise on CrOCl is only 15.4%of that on SiO_(2) and 30%on h-BN upon the same electric power density,indicating the efficient heat dissipation of graphene device on CrOCl.Our study provides new insights into two-dimentional(2D)dielectric material with high thermal conductivity and strong anisotropy for the application of thermal management in electronic devices.

关键词： CrOCl High thermal conductivity strong anisotropy efficient heat dissipation heat sink graphene devices

来源：

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

Numerical Analysis of Microchannels Designed for heat sinks

引用

Nanomanufacturing and Metrology 2022年第4期5卷 354-369页

作者： Matthew McCormack Fengzhou Fang Jufan Zhang Centre of Micro/Nano Manufacturing Technology(MNMT-Dublin) School of Mechanical&Materials EngineeringUniversity College DublinDublin 4Ireland State Key Laboratory of Precision Measuring Technology and Instruments Laboratory of Micro/Nano Manufacturing Technology(MNMT)Tianjin UniversityTianjin300072China

Conjugate heat transfer is numerically investigated using a three-dimensional computational fluid dynamics approach in various microchannel geometries to identify a high-performance cooling method for piezoelectric ceramic stacks and spindle units in high-precision machines.Straight microchannels with rectangular cross sections are first considered,showing the performance limitations of decreasing the size of the microchannels,so other solutions are needed for high applied heat fluxes.Next,many microchannel designs,focusing on streamwise geometric variation,are compared to straight channels to assess their performances.Sinusoidally varying channels produce the highest heat transfer rates of those studied.Thus,their optimization is considered at a channel width and height of 35 and 100μm,respectively.heat transfer increases as the amplitude and spatial frequencies of the channels increase due to increased interfacial surface area and enhanced Dean flow.The highest performance efficiencies are observed at intermediate levels of amplitude and frequency,with efficiency decreasing as these geometric parameters are increased further at the onset of flow separation.The sinusoidal channel geometries are then optimized with respect to minimizing the system’s pressure drop for all applied heat fluxes between 5690 and 6510 kW/m2.Doing so created an optimal geometry curve and showed that all geometries in this region had amplitudes close to 40μm.Therefore,imposing a fixed heat flux requirement for a case study of cooling piezoelectric ceramics,the optimized sinusoidal geometry decreases the system pressure drop by 79%relative to a straight channel while maintaining a larger minimum feature size.

关键词： Microchannel heat sink Conjugate heat transfer Numerical simulation

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：