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A Novel Layered Double Hydroxide and Dodecyl Alcohol Assisted PCM Composite with High Latent Heat Storage Capacity and Thermal Conductivity

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Journal of Thermal Science 2024年第2期33卷 537-547页

作者： AL-AHMED Amir SARI Ahmet KHAN Firoz AL-RASHEIDI Masoud Hekimoğlu Gökhan AFZAAL Mohammad A.ALSULAMI Ahmed DAFALLA Hatim SALHI Billel A.ALSULAIMAN Fahad Interdisciplinary Research Center for Renewable Energy and Power systems(IRC-REPS) King Fahd University of Petroleum&MineralsDhahran31261Saudi Arabia Department of Metallurgical and Material Engineering Karadeniz Technical UniversityTrabzon61080Turkey Maths and Natural Sciences division Higher Colleges of TechnologyP.O.Box 7947SharjahUnited Arab Emirates Department of Mechanical Engineering King Fahd University of Petroleum&MineralsDhahran31261Saudi Arabia Core Research Facilities King Fahd University of Petroleum&MineralsDhahran31261Saudi Arabia Interdisciplinary Research Center for Membranes and Water Security King Fahd University of Petroleum&MineralsDhahran31261Saudi Arabia

Dodecyl alcohol(DDA) is a promising solid-liquid phase change material(PCM) due to its favorable latent heat storage(LHS) ***,the leakage issue of PCM in a melted state during the heating period and low thermal conductivity restricts its utilization potential in thermal energy storage(TES) *** the same context,the present work aims to overcome the leakage issue and improve the thermal conductivity of the *** this in mind,a novel leak-proof layered double hydroxide(LDH)/DDA composite PCM is proposed through a solution-based impregnation *** leak-proof impregnation ratio of the DDA impregnated within the cavities of the synthesized Al/Fe-LDH was determined to be 60%.Detailed morphological,physicochemical,and thermal properties of the fabricated composite were studied by scanning electron microscopy(SEM),Fourier transforms infrared(FTIR) spectroscopy,X-ray diffraction(XRD)spectroscopy,differential scanning calorimetry(DSC),thermalgravimetric analysis(TGA),and thermal cycling *** results show that the LDH/DDA composite has a suitable phase change temperature(about 20℃) for passive solar thermal management of building *** composite PCM showed high LHS enthalpy(about136 J/g),good thermal stability,and cycling LHS *** also showed nearly 152% higher thermal conductivity compared to that of pure DDA,ultimately reducing the melting and solidification time of the pure DDA by 44.9% and 45.5%,respectively.

关键词： dodecyl alcohol layered double hydroxide composite PCM thermal conductivity thermal energy storage(TES)

Progress in the Secondary heating System for the HL-2A Tokamak

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Southwestern Institute of Physics Annual Report

Southwestern Institute of Physics Annual Report 2006年第1期 74-75页

In 2006, the following work on secondary heating systems for HL-2A tokamak have been done： the development of an electron cyclotron resonance heating （ECRH） system, the improvement of lower hybrid resonance heating... 详细信息

关键词： Auxiliary heating ECRH NBI

Property and Oxidation Behaviours of (Mo,Cr)Si2 + ZrO2 Composite Produced by Pressure-Less Sintering

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Journal of Materials Science and Chemical Engineering 2016年第7期4卷 15-21页

作者： Yiming Yao Erik Ström Xin-Hai Li Qin Lu Department of Materials and Manufacturing Technology Chalmers University of Technology Gothenburg Sweden heating systems division Sandvik Heating Technology AB Hallstahammar Sweden Material Technology Siemens Industrial Turbomachinery AB Finspong Sweden

A composites of (Mo0.9Cr0.1)Si2 + 15vol% ZrO2 was prepared with powder metallurgy and Pressure- Less Sintering (PLS) method, aiming at applications of high temperature structural materials. Mechanical properties of the composites were assessed with hardness, indentation fracture toughness Kc and KIC tested using SEVNB, flexure strength at room temperature and 1200?C, and isothermal oxidation at 1400?C. The results showed that the native silica oxide and molybdenum-oxides on the silicide feedstock surface were significantly reduced in terms of Cr-alloying. (Mo0.9Cr0.1)Si2 and its composite also exhibited improved sinterability and grain growth, owing to the presence of (Cr, Mo)5Si3 at grain boundaries. Fracture toughness of the composite was increased by a factor of 1.6 to that in the monolithic silicide. Mechanical property of the composite at high temperature was not affected by Cr addition. However, the high temperature oxidation resistance was greatly improved in the (Mo0.9Cr0.1)Si2 + 15vol% ZrO2 compared with the non Cr-alloyed counterpart. The Cr-alloying effects on the microstructure, fracture behaviour, and high temperature oxidation resistance were discussed.

关键词： MoSi2 Composite Fracture Toughness Mechanical Property Microstructure High Temperature Oxidation

Numerical Heat Transfer Modelling for Rapid Impact Assessment of Limiting Thermostat Reliability on Fuel-Oil Burner Pre-Heaters： A Case Study

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Journal of Environmental Science and Engineering(A) 2016年第6期5卷 298-311页

作者： Bans Elbuken heating division Alarko Carrier Research and Development Center GOSB Gebze 41480 Kocaeli Turkey

In this paper, the impact of limiting thermostat on the rupture event occuring in Fuel-Oil burner fuel pre-heaters＇ resistant （heat generating） wires is inspected numerically. Gaseous fuel content in the pipeline has also been issued as a possibility. Heater＇s inner temperature distributions have been simulated by an in-house MATrix LABoratory （MATLAB） script in order to understand the resistant wire exposure to high temperatures by numerous scenarios. It is concluded that the effect of fuel flowrate is not a major effect on the wires＇ fate because of the limiting thermostat co-working. The main difference between the calculations is the effect of thermostat cut off function. The numerical simulations enlightened the dominant effect of thermostat sensing delay, so the overheating event. Intolerable delay results with a quick drop in the thermal efficiency and an increased possibility on wire rupture due to overheating which means a burner malfunction. Referring to the first numerical simulation results, a distributed and reduced heat flux was implemented with the same fluid and thermodynamic properties on a revised pre-heater model with an increased heater plate. The increment, thus the reduction on the heat flux of the ribbon wires has been noted as the key for safe operation.

关键词： Fuel oil burner numerical simulations resistant wires rupture thermostat delay.

Pre-combustion mercury removal with co-production of hydrogen via coal electrolysis

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Journal of Environmental Sciences 2024年第2期136卷 382-389页

作者： Xiang Lyu Runming Tao Tianyu Zhang Chemical and Biomolecular Engineering Department Ohio University165 Stocker CenterAthensOH45701USA Electrification and Energy Infrastructures division Oak Ridge National LaboratoryOak RidgeTN37831USA Beijing Key Lab for Source Control Technology of Water Pollution College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China Engineering Research Center for Water Pollution Source Control&Eco-remediation College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China

Pre-combustion mercury removal via coal electrolysis was performed and investigated on a bench-scale coal electrolytic cell(CEC)systemically,and factorial design was used to determine the effect of different operating conditions(coal particle size,operating temperature,operating cell voltage,and flow rate of slurry)on the percentage of mercury removal,percentage of ash removal,and dry heating value *** results showed that the operating cell voltage,as well as the interaction between operating cell voltage and coal particle size,are significant factors in the percentage of mercury *** is no significant factor in the percentage of ash removal and the dry heating value change,but the coal could be purified while keeping the dry heating value almost constant after electrolysis.A co-product of hydrogen could be produced during coal electrolysis with 50%lower energy consumption compared with water ***,a mechanism for mercury removal in coal was *** facts indicate that coal electrolysis is a promising method for precombustion mercury removal.

关键词： Pre-combustion mercury removal Coal electrolysis Ash removal Dry heating value Hydrogen production

Influence of processing on microstructure and electrical characteristics of multilayer varistors

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Journal of Advanced Ceramics 2019年第3期8卷 408-417页

作者： D.SZWAGIERCZAK J.KULAWIK A.SKWAREK Institute of Electron Technology Kraków Division

The paper reports on the influence of processing on microstructure and electrical properties of multilayer varistors based on zinc oxide doped with Bi2O3,Sb2O3,Co2O3,MnO,Cr2O3,B2O3,and SiO2.0.5–1 wt%of AlF3–CaB4O7 was used as a new effective sintering *** behavior of green laminates during heating was characterized using differential thermal analysis and a heating *** revealed by XRD,SEM,and EDS methods,the varistor layers are composed of ZnO grains of 1–5μm size,submicrometer spinel and pyrochlore grains situated at the ZnO grain boundaries,and nanometric Bi2O3-rich films surrounding ZnO *** impedance studies carried out in the frequency range of 0.01 Hz–2 MHz at temperatures changing from –30 to 150℃ imply the formation of semiconducting grains and insulating grain *** dependence of dielectric permittivity shows a high plateau at lower frequencies,typical for barrier layer capacitance *** fabricated multilayer varistors show nonlinear current–voltage characteristics with a high nonlinear coefficient of 26–*** breakdown voltage was found to decrease within the range of 66–130 V with sintering temperature increasing from 1000 to 1100℃.Good surge current capability of the varistors was confirmed by the tests using 8/20μs pulses.

关键词： multilayer varistor tape casting microstructure current–voltage characteristic

Effects of solution heat treatment on corrosion resistance of 5083F Al alloy

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中国有色金属学会会刊：英文版 2009年第4期19卷 887-891页

作者： Seong-Jong KIM Seok-Ki JANG division of Marine Engineering Mokpo Maritime University

Aluminum alloys are used as substitutes for fiber reinforced polymer(FRP) in ships and ***,ships constructed with 5000-series Al alloy suffer a little corrosion in the marine environment,when they run in high speed,and high flow rate,***,solution heat treatment was carried out to prevent *** optimal heat treatment involved heating specimens for 120 min at 420 ℃ and then cooling them in *** addition,the optimal ageing condition involved ageing specimens for 240 min at 180 ℃.The slow strain rate test(SSRT) in a seawater revealed that heat treatment under optimal conditions produced improved elongation,time-to-fracture and amount of dimples compared with the as-received specimen.

关键词：铝合金腐蚀性固溶处理热处理生产纤维增强聚合物电阻慢应变速率海洋环境

Mechanical properties of high-strength concrete subjected to high temperature by stressed test

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中国有色金属学会会刊：英文版 2009年第B09期19卷 128-133页

作者： Gyu-Yong KIM Young-Sun KIM Tae-Gyu LEE division of Architecture Engineering Chun gnam National University

Recently, the effects of high temperature on compressive strength and elastic modulus of high strength concrete were experimentally investigated. The present study is aimed to study the effect of elevated temperatures ranging from 20 ℃ to 700 ℃ on the material mechanical properties of high-strength concrete of 40, 60 and 80 MPa grade. During the strength test, the specimens are subjected to a 25% of ultimate compressive strength at room temperature and sustained during heating, and when the target temperature is reached, the specimens are loaded to failure. The tests were conducted at various temperatures (20-700 ℃) for concretes made with W/B ratios of 46%, 32% and 25%, respectively. The results show that the relative values of compressive strength and elastic modulus decrease with increasing compressive strength grade of specimen.

关键词：高强混凝土高温作用力学性能测试抗压强度温度升高弹性模量强度试验

Temperature Distribution and Thermal Stresses in Various Conditions of Moving heating Source during Line heating Process

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Journal of Thermal Science 2012年第1期21卷 82-87页

作者： Yoon Hwan Choi Yeon Won Lee Kwang Choi Deog Hee Doh Kyoung Joon Kim Department of Mechanical and Automotive Engineering Pukyong National University Steel Structure Research division Research Institute of Industrial Science & Technology division of Mechanical and information Engineering Korea Maritime University

Line heating method is widely used to manufacture curved surfaces in ship building. The main factors governing the quality of the manufactured products are the moving velocity of the heating source, heating strength, and heating ways. In this study, the temperature distributions of the heated plate were investigated with the condition that the line heating process was automatic. The temperature variations were also investigated with the changes of those three variables. The numerical results showed that the peak temperature decreased as the moving velocity of the heating source increased. It also revealed that the peak temperatures changed linearly with the changes of the heating source.

关键词： Moving heat source Line heating Thermal stress Residual deformation Conductive heat transfer