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Dust-Induced Regulation of Thermal Radiation in Water Droplets
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作者 张传新 李天骄 +1 位作者 须留钧 黄吉平 《Chinese Physics Letters》 SCIE EI CAS CSCD 2023年第5期52-57,共6页
Accurate and fast prediction of thermal radiation properties of materials is crucial for their potential applications.However,some models assume that the media are made up of pure water droplets,which do not account f... Accurate and fast prediction of thermal radiation properties of materials is crucial for their potential applications.However,some models assume that the media are made up of pure water droplets,which do not account for the increasing deviations caused by volcanic eruptions,pollution,and human activities that exacerbate dust production.The distinct radiation properties of water and dust particles make it challenging to determine the thermal radiation properties of water droplets containing dust particles.To address this issue,we investigate the influence of dust particles on light transmission and energy distribution in water droplets using the multiple sphere T-matrix method.By considering different droplet and dust diameters,volume fractions,and position distributions,we analyze how extinction regulation is achieved in dust-containing water droplets.Our results reveal the significant role of dust particles in the thermal radiation effect and provide insights into the electromagnetic properties of colloidal suspensions.Moreover,the dust-induced reestablishment of energy balance raises concerns about environmental management and climate change.This research highlights the importance of accounting for dust particles in atmospheric models and their potential impact on radiative balance. 展开更多
关键词 THERMAL DIAMETERS EXTINCTION
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Reconstruction model for temperature and concentration profiles of soot and metal-oxide nanoparticles in a nanofluid fuel flame by using a CCD camera 被引量:2
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作者 刘冠楠 刘冬 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第5期334-343,共10页
This paper presents a numerical study on the simultaneous reconstruction of temperature and volume fraction fields of soot and metal-oxide nanoparticles in an axisymmetric nanofluid fuel sooting flame based on the rad... This paper presents a numerical study on the simultaneous reconstruction of temperature and volume fraction fields of soot and metal-oxide nanoparticles in an axisymmetric nanofluid fuel sooting flame based on the radiative energy images captured by a charge-coupled device(CCD) camera. The least squares QR decomposition method was introduced to deal with the reconstruction inverse problem. The effects of ray numbers and measurement errors on the reconstruction accuracy were investigated. It was found that the reconstruction accuracies for volume fraction fields of soot and metaloxide nanoparticles were easily affected by the measurement errors for radiation intensity, whereas only the metal-oxide volume fraction field reconstruction was more sensitive to the measurement error for the volume fraction ratio of metaloxide nanoparticles to soot. The results show that the temperature, soot volume fraction, and metal-oxide nanoparticles volume fraction fields can be simultaneously and accurately retrieved for exact and noisy data using a single CCD camera. 展开更多
关键词 电荷耦合器件 金属氧化物 照相机 煤烟 温度 重建模型 火焰 燃料
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Effects of dimethyl ether and ethanol additions on soot transition in ethylene counterflow diffusion flames
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作者 GUO LinGe YING YaoYao +2 位作者 CHEN Chen ZHAO Xuan LIU Dong 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2024年第4期1094-1112,共19页
This paper investigates the effect of blending dimethyl ether(DME)and ethanol on the soot transition periods in ethylene counterflow diffusion flames by using a novel optical diagnostic method.The soot critical transi... This paper investigates the effect of blending dimethyl ether(DME)and ethanol on the soot transition periods in ethylene counterflow diffusion flames by using a novel optical diagnostic method.The soot critical transition point in different conditions is identified experimentally and numerically.Two kinds of flames are carried out to gain the soot critical transition point in counterflow diffusion flames by changing oxygen fraction(Xo)and changing volume flow rates of fuel and oxidizer(Qv).The red-green-blue(RGB)ratio method is used to precisely identify the soot critical transition point,and chemical kinetic simulations are performed to analyze the detailed reaction paths.The results show that compared to the ethylene flame,the soot critical transition point occurs at a higher Xoand a lower Qvwhen DME or ethanol is blended.The addition of DME and ethanol can inhibit soot formation,due to the degree of soot formation reaction being lower than the degree of the oxidation reaction in the blending flames. 展开更多
关键词 optical diagnosis sooting tendency counterflow diffusion flame dimethyl ether ETHANOL
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Sensitivity analysis of modeling parameters to soot and PAHs prediction in ethylene inverse diffusion flame
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作者 WU BingKun LI TianJiao LIU Dong 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2024年第2期486-498,共13页
The soot formation model based on inverse ethylene diffusion flames was performed to study the sensitivity of the soot formation process to the prediction results.The effects of efficiency parameters such as soot ince... The soot formation model based on inverse ethylene diffusion flames was performed to study the sensitivity of the soot formation process to the prediction results.The effects of efficiency parameters such as soot inception,surface growth and coagulation on the simulation results were studied by using the adjustable efficiency model.In addition,the reversible soot model and conjugate heat transfer(CHT)model were also introduced to explore their advantages.Results indicated that,among adjustable efficiency parameters,the nucleation efficiency had the greatest influence on the predicted soot and PAHs distributions,while the Habstraction-C2H2-addition(HACA)process and PAH adsorption surface growth efficiencies impacted little.The adjustable efficiency parameters had a significant effect on the concentration of soot gaseous precursors and soot particles,but their effects on temperature,gas phase molecules,and intermediate species were not obvious.When the nucleation efficiency increased from 2×10^(-6)to 1×10^(-4),the predicted value of the integrated soot was increased by nearly 50%,and the maximum primary particle number density and the number of aggregates were increased by an order of magnitude.The maximum concentration of BAPYR was doubled.However,the peak temperature along the axial direction increased by only 3.5 K.Using the reversible soot model,the approximation results of the adjustable efficiency parameters could be modified,which showed the feasibility of the model.The use of the CHT model promoted pyrolysis of the fuel below the outlet of the fuel tube,with high-temperature zones,soot zones,and PAHs zones moving towards higher flame heights.Besides,when using the reversible model and the CHT model,the maximum soot volume fraction decreased by 39%compared with the basic efficiency parameters,while the concentration of BAPYR increased by 162%,and the concentrations of gas phase species were decreased. 展开更多
关键词 inverse diffusion flames soot formation soot model ETHYLENE
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Coupled interactive effects of ammonia and hydrogen additions on ethylene diffusion flames: A detailed kinetic study
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作者 XIAO JiaYi XU TingTing +5 位作者 SHU ZhiMei DENG QiGe ZHAO Xuan YING YaoYao LI TianJiao LIU Dong 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2024年第3期930-948,共19页
In order to create effective combustion technologies and fuels with low or no carbon emissions,the research was conducted to assess the coupled interactive effects of NH_(3) and H_(2) additions on ethylene counterflow... In order to create effective combustion technologies and fuels with low or no carbon emissions,the research was conducted to assess the coupled interactive effects of NH_(3) and H_(2) additions on ethylene counterflow diffusion flames from a kinetic perspective.The effects of the NH_(3)/H_(2) combination on flame temperatures,major species,key radicals,important intermediate species,representative oxygenated species and NO_xwere examined.The results of the study utilizing fictitious inert NH_(3) and/or H_(2) revealed the chemical effects of the two components.It was found that the NH_(3)/H_(2) coupled effects had a more effective inhibitory effect on soot precursors than the effects of corresponding sum of single NH_(3) or H_(2) addition.The production of soot precursors was promoted by the coupled chemical effects of NH_(3) and H_(2),but the coupled dilution and thermal effects were observed to have a greater impact,resulting in a decrease of the mole fractions of soot precursors.As for the interaction of NH_(3) and H_(2) effects,the presence of H_(2) decreased the chemical effects of NH_(3) on the augmentation of C_(2)H_(2),A1,A2,and CH_(3)CHO mole fractions.The NH_(3) addition alleviated the H_(2) chemical effects on increasing C_(2)H_(2),C_(3)H_(3),A1 and A2 concentrations.Conversely,the NH_(3)chemical effects on C_(3)H_(3),OH and CH_(3)CHO were enhanced when H_(2) was added.The presence of NH_(3) augmented the chemical effects of H_(2) on the growth of OH mole fraction.Moreover,the H_(2) chemical effects hindered the production of NO and NO_(2) in the presence of NH_(3). 展开更多
关键词 NH_(3)/H_(2)addition kinetic analysis coupled interactive effects chemical effects
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Experimental study on effects of gas flow rate on soot characteristics in diffusion flames coupled with plasma
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作者 QI DanDan CHEN MingXiao +1 位作者 TU Xin LIU Dong 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2024年第2期475-485,共11页
This study examined the evolution of morphology and nanostructure of soot particles from the plasma-flame interaction for various gas flow rates.The current study used both optical diagnostic and sampling methods to e... This study examined the evolution of morphology and nanostructure of soot particles from the plasma-flame interaction for various gas flow rates.The current study used both optical diagnostic and sampling methods to explore the soot production and combustion characteristics.Soot particles were characterized at the same positions downstream from the flame zone by thermophoretic sampling and transmission electron microscopy.Moreover,X-ray diffraction analysis,and thermogravimetric analysis were performed to study the nanostructure and oxidation reactivity of soot.A reduction in soot concentration was found with the plasma addition,which illustrated an inhibition effect of plasma on soot emission.The increased gas flow rate promoted soot concentration since a growing number of carbons participated in the combustion process.Depending on the gas flow rate(carbon content)variation and plasma activation,either liquid-like soot material with irregularly shaped protrusions or chain-like structure,or a mixture of both,were generated from the diffusion flames.The soot produced by plasma-flame interaction also demonstrated a high correlation between nanostructure and reactivity.The soot from lower carbon content with plasma activation had a shorter fringe length and larger fringe tortuosity related to higher oxidation reactivity.On the contrary,soot from the highest carbon content without plasma-flame interaction exhibited prevalent fullerene-like nanostructures with evident large or small shells and also had a higher carbonization degree resulting in lower oxidation reactivity. 展开更多
关键词 soot characteristics gas flow rate PLASMA diffusion flames
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Studies on preparation and thermal control behavior of hybrid fillers/binary-polymer composites with positive temperature coefficient characteristic
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作者 YU AiMei LI Qiang 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2021年第7期1447-1458,共12页
Conductive polymer composites(CPCs) as the thermo-sensitive materials have attracted much attention in thermal control field due to their reliable self-regulating behaviors, high efficiency and mechanical flexibility.... Conductive polymer composites(CPCs) as the thermo-sensitive materials have attracted much attention in thermal control field due to their reliable self-regulating behaviors, high efficiency and mechanical flexibility. However, the development of these materials needs to manage the normal conflicting requirements, such as effective heating performance and good self-regulating capability. This paper presents a series of novel CPCs material having different amounts of hybrid fillers of multi-walled carbon nanotubes(CNTs) and carbon black(CB). The positive temperature coefficient intensity is enhanced to 105.2, and the roomtemperature resistivity is optimized to 320 ? cm. Besides, the Curie temperatures are regulated to room-temperature range by incorporating the low-melting-point blend matrix into the poly(ethylene-co-vinyl acetate)/CNTs/CB composite. The thermalcontrol experiment demonstrates that CPCs-heating elements can adjust the equilibrium temperature of controlled equipment near their Curie temperatures without any control methods. Compared with the ordinary resistor, the CPCs materials have the remarkable adaptive thermal control behavior. Furthermore, the temperature control capability is particularly prominent in the changing environment temperature. The CPCs as a safe and reliable adaptive heating element is potential to replace the conventional active thermal control means. 展开更多
关键词 positive temperature coefficient room-temperature Curie point adaptive thermal control CPCs materials
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Thermal design of a novel heat sink cooled by natural convection with phase transition in the series loop 被引量:4
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作者 CHEN Hao LI Qiang 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2018年第11期1732-1744,共13页
In this paper, a novel heat sink, cooled by natural convection, with phase transition in the circulation loop was designed, and the heat sink was applied on averaging temperature and cooling the electronic equipment. ... In this paper, a novel heat sink, cooled by natural convection, with phase transition in the circulation loop was designed, and the heat sink was applied on averaging temperature and cooling the electronic equipment. The working fluid in the heat sink was driven by the capillary pump. Numerical simulations were performed, to study the heat transfer performance of two systems with various heating power, filling ratios and refrigerants. The influences of above elements on temperature uniformity of two systems were also studied and the thermal performances of two systems were compared. The volume of fluid(VOF) model was utilized to simulate fluid motion in ANSYS FLUENT. The simulation results indicate that the temperature differences of the system comprising two substrates(system 1) are very small under suitable filling ratio conditions, and the thermal performance of system 1 is preferable to the system comprising one substrate(system 2) at the same volume. Besides, the simulation results also show that the system using R245 fa possesses excellent temperature uniformity for the same filling ratio and heating power.Finally, the experiments were investigated and the experimental results proved the correctness of the theoretical model. 展开更多
关键词 natural CONVECTION vapor CHAMBER CIRCULATION LOOP filling ratio temperature difference
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Design of a widely adjustable electrochromic device based on the reversible metal electrodeposition of Ag nanocylinders
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作者 Jiangrong Zhou Yuge Han 《Nano Research》 SCIE EI CSCD 2023年第1期1421-1429,共9页
Structural colors resulting from nanostructured metallic surfaces hold a series of advantages compared to conventional chemical pigments and dyes,such as enhanced durability,tunability,scalability,and low consumption,... Structural colors resulting from nanostructured metallic surfaces hold a series of advantages compared to conventional chemical pigments and dyes,such as enhanced durability,tunability,scalability,and low consumption,making them particularly promising for preparing color-tunable devices.However,once these structures are fabricated,they are almost all passive devices with static nanostructures and fixed optical properties,limiting their potential applications.Here,by using a specially designed array of ordered SiO2 nanoholes as a deposition template in conjunction with the traditional reversible metal electrodeposition device(RMED),we propose a tunable reflective surface where the color of the surface can be changed as a function of the thickness of the deposited Ag nanoparticles(AgNPs).Simplified manufacturability and a large range of color tunability are achieved over previous reports by utilizing the SiO2 nanohole template,which allows the direct deposition of AgNPs while forming an array structure of Ag nanocylinders.Besides,a further thematic analysis of the physical mechanism in the proposed structure is conducted.The results show that the structural colors induced by the longitudinal localized surface plasmon resonance(LSPR)mode can be dynamically tuned from brown to purple via increasing the deposition thickness.Additionally,in combination with SiO2 nanohole templates of varying parameters,a full gamut of colors spanning the entire visible spectrum is achieved,revealing the feasibility of utilizing the properties of the LSPR mode for satisfying various color requirements.We believe that this LSPRbased multicolor RMED design will contribute to the development of full color information displays and light-modulating devices. 展开更多
关键词 structural color dynamic color tunability nanocylinder plasmonic nanostructures
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Experimental and Numerical Study of Non-Premixed Dimethyl Ether/Methane-Air Hot Flame at Elevated Pressures
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作者 CAO Jin ZHOU Xun +2 位作者 ZHANG Rui YANG Shenghua LIU Dong 《Journal of Thermal Science》 SCIE EI CAS CSCD 2023年第1期401-413,共13页
Methane has a narrow range of flammable limits,low flame speed and poor ignition characteristics,which limit its utilization in internal combustion engines.However,this issue can be remedied through the use of CH_(4)/... Methane has a narrow range of flammable limits,low flame speed and poor ignition characteristics,which limit its utilization in internal combustion engines.However,this issue can be remedied through the use of CH_(4)/DME blends,because DME has better ignition and combustion characteristics.In this study,the effects of pressure and blending ratio on the combustion characteristics of CH_(4)/DME blended fuels were investigated by using a high-pressure diffusion counterflow system,a constant volume combustion bomb,and CHEMKIN software.The reaction pressures are 0.1 MPa,0.2 MPa,0.3 MPa,and the blending ratios are 100%DME,75%DME+25%CH_(4),50%DME+50%CH_(4)and 25%DME+75%CH_(4)(mol%).The results show that the laminar flame speed,flame temperature,and extinction limit of CH_(4)/DME blended fuel decrease as the CH_(4)blending ratio or pressure increases.CH_(4)addition and increasing pressure both lead to the competition for OH and H radicals between CH_(4)and DME.However,the increase of CH_(4)mole fraction can also increase the path flux of CH_(4)+H=CH_(3)+H_(2),while the increase of pressure can decrease this path flux.Moreover,increasing pressure can promote all reaction processes and reaction rates. 展开更多
关键词 COUNTERFLOW high-pressure DME CH4 extinction limit
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Design and heat transfer analysis of a compound multi-layer insulations for use in high temperature cylinder thermal protection systems 被引量:2
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作者 CHEN MengJun ZHANG Ping LI Qiang 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2018年第7期994-1002,共9页
Thermal protection systems are very essential for high temperature thermal conductivity measurement system to reduce the heat loss to environment at the range of 600–1800 K. A compound multi-layer insulations structu... Thermal protection systems are very essential for high temperature thermal conductivity measurement system to reduce the heat loss to environment at the range of 600–1800 K. A compound multi-layer insulations structure which composed of inner carbon fibrous materials and outer alternately arranged alumina fibrous materials and high reflectivity foils is proposed for use in high temperature cylinder thermal protection systems. A coupled conductive and radiation governing equations is presented for heat transfer analysis of the structure. The finite volume method and the discrete ordinate method are used to solve the governing equations. The optimization structure of the compound multi-layer insulations is investigated by considering the pressure of the gas, the density of the carbon fibrous materials, the density of the alumina fibrous materials, the number of reflective foil layers and the emissivity of reflective foils. The results show that the compound structure has the best thermal insulation performance when the pressure of the gas is below 0.01 k Pa, the density of carbon fibrous materials is 180 kg m^(-3), the density of alumina fibrous materials is 256 kg m^(-3) and the number of reflective foil layers is 39. In addition, the thermal insulation performance is much better when the emissivity of reflective foils is lower. 展开更多
关键词 热保护系统 屏蔽结构 高温度 热转移 柱体 混合物 高反射率 设计
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Combustion characteristics and synergy behaviors of biomass and coal blending in oxy-fuel conditions: A single particle co-combustion method 被引量:9
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作者 ZHANG Rui LEI Kai +2 位作者 YE BuQing CAO Jin LIU Dong 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2018年第11期1723-1731,共9页
Co-combustion biomass and coal can effectively reduce the emission of CO_2. O_2/H_2O combustion is regarded as the next generation of oxy-fuel combustion technology. By co-combustion biomass and coal under oxy-fuel co... Co-combustion biomass and coal can effectively reduce the emission of CO_2. O_2/H_2O combustion is regarded as the next generation of oxy-fuel combustion technology. By co-combustion biomass and coal under oxy-fuel condition, the emission of CO_2 can be minimized. This work investigates the co-combustion characteristics of single particles from pine sawdust(PS) and bituminous coal(BC) in O_2/N2, O_2/CO_2 and O_2/H_2O atmospheres at different O_2 mole fractions(21%, 30% and 40%). The experiments were carried out in a drop tube furnace(DTF), and a high speed camera was used to record the combustion process of fuel particles. The combustion temperature was measured by a two-color method. The experiments in O_2/N2 atmosphere indicate that the particles from pine sawdust and bituminous coal all ignite homogeneously. After replacing H_2O for N2, the combustion temperature of volatiles of blended fuel particles decreases, while the combustion temperature of char increases. The ignition delay time in O_2/H_2O atmosphere is shorter than that in O_2/N2 or O_2/CO_2 atmosphere. The combustion temperature of volatiles of blended fuel particles increases as the mass fraction of bituminous coal increases, while the combustion temperature of char of blended fuel particles is higher than that of biomass or bituminous coal. The ignition delay time of blended fuel particles increases with the increasing mass fraction of bituminous coal, and the experimental ignition delay time of blend fuel particles is shorter than the theoretical one. These reveal a synergy during co-combustion process of pine sawdust and bituminous coal. 展开更多
关键词 CO-COMBUSTION O2/H2O single particle BIOMASS and coal SYNERGY
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Numerical study on flow and heat transfer characteristics of microchannel designed using topological optimizations method 被引量:5
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作者 HU DingHua ZHANG ZhiWei LI Qiang 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2020年第1期105-115,共11页
Microchannel has demonstrated advantages in the thermal management of integrated chip. In this study, the topology optimization method is applied for designing a topological microchannel to optimize the performances o... Microchannel has demonstrated advantages in the thermal management of integrated chip. In this study, the topology optimization method is applied for designing a topological microchannel to optimize the performances of both heat dissipation and pressure drop. To validate the performance of the topological structure, the flow and heat transfer characteristics of topological microchannel under non-uniform heating flux are numerically studied. The topological structure is designed to cool a heating area of 10 mm×10 mm with 4 hotspots. Heat flux is 40 W/cm^2 in the hotspot area, while it is only 15 W/cm^2 in the rest heating area. The results of heat dissipation performance and pressure drop are compared with those of conventional straight microchannel. Numerical result shows that, compared to the straight microchannel, the hotspot temperature and pressure drop of topological microchannel can be reduced by 4 and 0.6 k Pa, respectively, under the flow rate of 2.2×10^-4 kg/s. The coefficient of performance(COP) of topological microchannel can be 16.1% better than that of straight microchannel, which can be attributed to the effects of optimized bifurcation and confluence structural of topological microchannel. 展开更多
关键词 topology optimization MICROCHANNEL heat dissipation pressure drop HOTSPOT
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Numerical study on two-phase boiling heat transfer performance of interrupted microchannel heat sinks 被引量:4
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作者 ZHOU JianHong CHEN XueMei LI Qiang 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2022年第3期679-692,共14页
The conventional straight microchannel heat sinks have been reported to inadequately remove the increasing power density of electronics.In recent years,an effective heat transfer enhancement method,flow disruptions ha... The conventional straight microchannel heat sinks have been reported to inadequately remove the increasing power density of electronics.In recent years,an effective heat transfer enhancement method,flow disruptions have attracted the attention of researchers,where interrupted structures are arranged in the microchannel to enhance flow mixing and heat transfer.However,previous numerical studies of interrupted microchannel heat sinks(I MCHS)mainly focus on single-phase flow condition,and the characteristics of the boiling heat transfer of I MCHS in two-phase flow condition have been rarely explored.Thus,the flow and heat transfer characteristics of two I MCHS based on rectangular microchannel heat sink(R MCHS)are investigated by modeling both single-phase and two-phase flow conditions.These two interrupts consist of a combination of cavities and ribs,namely elliptical cavities and elliptical side ribs(EC-ESR),and elliptical cavities and elliptical central ribs(EC-ECR).The results show that for single-phase flow condition,the maximum Nusselt number is increased by 187%in the EC-ESR design and150%in the EC-ECR design compared with the R MCHS.For subcooled boiling(i.e.,two-phase flow)condition,the EC-ECR design is a promising structure to enhance boiling heat transfer with 6.7 K reduction of average wall temperature and 29%increment of local heat transfer coefficient when compared with those of R MCHS.However,the local heat transfer coefficient in the EC-ESR design is decreased by 22%compared with the R MCHS due to the formation of a rare flow pattern(i.e.,inverted annular flow with vapor film separation)in the microchannel.This flow pattern can induce departure from nucleate boiling(DNB),thereby deteriorating the heat transfer on the channel walls. 展开更多
关键词 microchannel heat sink cavities and ribs thermal performance flow pattern boiling heat transfer flow disruptions
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Experimental study of a novel heat sink for distribution level static synchronous compensator cooling 被引量:4
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作者 CHEN Hao LI Qiang 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2020年第9期1764-1775,共12页
In this paper, a novel heat sink which coupling natural convection and phase transition was designed to meet the cooling requirements of distribution level static synchronous compensator(DSTATCOM). The two inclined ev... In this paper, a novel heat sink which coupling natural convection and phase transition was designed to meet the cooling requirements of distribution level static synchronous compensator(DSTATCOM). The two inclined evaporation substrates can meet the requirements for the parallel operation of DSTATCOM and the working medium R245 fa was driven by gravity and buoyancy in the heat sink. The influence of filling ratio and heating power on the thermal performance of the heat sink was investigated experimentally and theoretically. The experimental results showed that the filling ratio and heating power had a significant influence on the thermal performance of the heat sink. At the ambient temperature of 25℃, the heat sink could start up successfully at different heating power and filling ratio. Meanwhile, the heat sink achieved good heat dissipation performance as the maximum temperature of two evaporation substrates were 60.14℃ and 67.85℃ while the heating power was 3000 Wand the filling ratio was 80%. The heat transfer resistance between two evaporation substrates and condensation substrates were6.6×10^-3℃/W and 1.2×10^-2℃/W at the same working condition. Additionally, the experimental results showed a good agreement with the calculated results. 展开更多
关键词 natural convection phase transition thermal performance maximum temperature heat transfer resistance
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Formation and characteristics of soot from pyrolysis of ethylene blended with furan fuels 被引量:4
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作者 ZHANG LiJie LIU Dong 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2021年第3期585-598,共14页
As two renewable oxygenated biofuels,2,5-dimethylfuran and 2-methylfuran(DMF and MF)have been considered to be two of the most potential fuels in the future due to the development of the second-generation biosynthetic... As two renewable oxygenated biofuels,2,5-dimethylfuran and 2-methylfuran(DMF and MF)have been considered to be two of the most potential fuels in the future due to the development of the second-generation biosynthetic technologies.The atmosphere pyrolysis experiments with 0%,25%,50%,75%and 100%replacement of ethylene by DMF/MF at 1173 and 1273 K were conducted.Collected soot samples were characterized by high resolution transmission electron microscopy(HRTEM)and thermogravimetric analysis(TGA)to acquire their internal structure and oxidation reactivity.Results showed that soot mass was positively related with DMF addition ratios and the reaction temperature.Soot production was also enhanced when the MF addition ratio gradually increased from 0%to 75%.The influences of DMF addition can promote soot formation more obviously than MF.Temperatures showed a more significant influence on soot morphology than fuel types and DMF/MF addition ratios.For a fixed addition ratio of DMF/MF,soot showed liquid-like substances at 1173 K.At 1273 K,approximately round particles formed and linked together in chains.Moreover,at 1273 K,the aggregates obtained by adding MF contained more single particles,longer carbon chains,and larger projection area compared with the aggregates by adding same MF.For nanostructures,as the addition ratios of DMF/MF increased,as well as the reaction temperature improved,the fringe length of the carbon layer increased,the average fringe tortuosity decreased,and the stacking arrangement of soot became more orderly,the soot oxidation reactivity was lower.Under a same addition ratio and reaction temperature,soot obtained by adding DMF possessed slightly longer fringe length,smaller fringe tortuosity and lower oxidation reactivity than those of the soot obtained by adding MF.High correlation between fringe parameters and soot oxidation reactivity was discovered.The more ordered soot nanostructure,the longer fringe length,and the smaller fringe tortuosity could make the oxidation reactivity of soot get lower. 展开更多
关键词 SOOT PYROLYSIS furan fuels NANOSTRUCTURE REACTIVITY
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Study on positive temperature coefficient of resistivity of co-doped BaTiO_3 with Curie temperature in room temperature region 被引量:2
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作者 YU AiMei LI Qiang +1 位作者 FAN DeSong ZHANG HongLiang 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2019年第5期811-819,共9页
As a temperature self-regulating heater material, the doped BaTiO_3 exhibits an attractive application perspective in the thermal management of electrical devices. However, the high Curie temperature does not meet the... As a temperature self-regulating heater material, the doped BaTiO_3 exhibits an attractive application perspective in the thermal management of electrical devices. However, the high Curie temperature does not meet the requirement in the thermal control application. In this work,(Ba_(0.997-x)Ce_(0.003)Sr_x)(TiNb_(0.002))O_3(x=0.2, 0.3, 0.35, abbreviated as BCSTNs) ceramics were prepared by the solid-state reaction method. The purpose of doping different content of strontium is to shift the Curie temperature of BaTiO_3-based ceramic to the ambient temperature region, maintaining excellent PT_C effect and low room-temperature resistivity by codoped cation ions in Ba-and Ti-site. The influences of sintering temperature and soak time on the microstructure as well as electrical properties of BCSTNs ceramics have been studied. The X-ray diffraction reveals that the composition with x=0.35 exhibits the coexistence of tetragonal and cubic lattice symmetries, confirmed by the Rietveld structure refinement. The dense microstructure with average grain sizes 0.84–7.87 μm was observed for BCSTN ceramics. Temperature-resistivity measurements demonstrate that T_C of the ceramics with x=0.35 shifted to the room temperature region. Additionally, the BCSTN ceramic with heavy doping Sr exhibits relative low room-temperature resistivity and the resistance jump greater than 2.0 orders of magnitude. 展开更多
关键词 electrical heating CO-DOPED BATIO3 CURIE TEMPERATURE positive TEMPERATURE coefficient of RESISTIVITY
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Thermodynamic and economic analyses of a coal and biomass indirect coupling power generation system 被引量:3
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作者 Buqing YE Rui ZHANG +3 位作者 Jin CAO Bingquan SHI Xun ZHOU Dong LIU 《Frontiers in Energy》 SCIE CSCD 2020年第3期590-606,共17页
The coal and biomass coupling power genera-tion technology is considered as a promising technology for energy conservation and emission reduction.In this paper,a novel coal and biomass indirect coupling system is prop... The coal and biomass coupling power genera-tion technology is considered as a promising technology for energy conservation and emission reduction.In this paper,a novel coal and biomass indirect coupling system is proposed based on the technology of biomass gasification and co-combustion of coal and gasification gas.For the sake of comparison,a coal and biomass direct coupling system is also introduced based on the technology of co-combustion of coal and biomass.The process of the direct and the indirect coupling system is simulated.The thermodynamic and economic performances of two systems are analyzed and compared.The simulation indicates that the thermodynamic performance of the indirect coupling system is slightly worse,but the economic performance is better than that of the direct coupling system.When the blending ratio of biomass is 20%,the energy and exergy fficiencies of the indirect coupling system are 42.70%and 41.14%,the intemal rate of returm(IRR)and discounted payback period(DPP)of the system are 25.68%and 8.56 years.The price fluctuation of fuels and products has a great influence on the economic performance of the indirect coupling system.The environmental impact analysis indicates that the indirect coupling system can inhibit the propagation of NOx and reduce the environmental cost. 展开更多
关键词 BIOMASS indirect coupling system process simulation thermodynamic analysis economic analysis
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Combustion characteristics of nanofluid fuels in a half-opening slot tube 被引量:2
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作者 LIU GuanNan LIU Dong 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2017年第7期1075-1087,共13页
Combustion characteristics of nanofluid fuels containing aluminum nanoparticles were investigated in half-opening slot tubes from the fundamental view. The effects of particle loading rates(0.25% and 2.5% by weight), ... Combustion characteristics of nanofluid fuels containing aluminum nanoparticles were investigated in half-opening slot tubes from the fundamental view. The effects of particle loading rates(0.25% and 2.5% by weight), type of base fuels(ethanol and butanol),and fuel flow rates(0.2, 0.6, and 1 mL/min) were studied in details. The combustion characteristics of the nanofluid fuels and pure based fuels were also examined to provide a comparison. Flame was unstable with reignition, stable state, nearly extinguishment repeatedly at low flow rate. At medium flow rate, flame height was increased and flame tended to be stable. At high flow rate,flame became unstable and was disturbed by the droplet forming and dripping significantly. Al atoms inside the oxide layer should be melted before the particles combustion, while Al oxide layer should be melted before the particles aggregates combustion. The effects of particles on the combustion characteristics, especially on the evaporation rate of base fuel, were discussed. The reasons for various combustion phenomena of nanofluid fuels were given, which can provide the useful guidance for the experimental research and practical applications of nanofluid fuels. 展开更多
关键词 流体燃料 燃烧特性 槽管 纳米粒子 火焰高度 颗粒燃烧 稳定状态 铝氧化物
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Soot reduction by addition of dimethyl carbonate in normal and inverse ethylene diffusion flames:Nanostructural evidence 被引量:1
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作者 Chutikarn Paladpokkrong Dong Liu +2 位作者 Yaoyao Ying Wei Wang Rui Zhang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2018年第10期107-117,共11页
Oxygenated fuel represents an attractive alternative as an additive for reducing soot emissions.Dimethyl carbonate(DMC) is an oxygenated compound which is a good option to reduce soot,but the detailed characteristics ... Oxygenated fuel represents an attractive alternative as an additive for reducing soot emissions.Dimethyl carbonate(DMC) is an oxygenated compound which is a good option to reduce soot,but the detailed characteristics of soot produced from combustion of hydrocarbon fuels blended with DMC are still lacking. The present research studied the nanostructure and reactivity of soot particles in ethylene/DMC normal and inverse diffusion flames. High resolution transmission electron microscopy(HRTEM), X-ray diffraction(XRD), and thermogravimetric analysis(TGA)were used to analyze the nanostructure and reactivity of soot. It was found that DMC addition was effective in decreasing the average weights of soot formed in flames. The results of HRTEM images showed that soot particles obtained with DMC addition showed liquid-like material and tight bonding, and exhibited more highly disorganized layers, which give it higher reactivity than soot obtained without DMC addition. Furthermore, HRTEM was used to analyze soot fringe characteristics consisting of fringe tortuosity, fringe length, and fringe separation. XRD was used to crosscheck the results for fringe separation, and was consistent with HRTEM results. In addition, the mass loss curve of TGA experiments showed that DMC addition could enhance the reactivity of soot particles. 展开更多
关键词 碳酸盐 煤烟 火焰 乙烯 直接数字控制 HRTEM 证据 氧化燃料
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