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Experiments and Analyses on Heat Transfer Characteristics from a Solid Wall to a Strip-ShapedWick Structure
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作者 Kenta Hashimoto Guohui Sun Yasushi Koito 《Frontiers in Heat and Mass Transfer》 EI 2024年第3期687-702,共16页
Centered or striped wick structures have been used to develop ultrathin heat pipes.Differing from traditional heat pipes,the centered or striped wick structures leave noncontact container surfaces with the wick struct... Centered or striped wick structures have been used to develop ultrathin heat pipes.Differing from traditional heat pipes,the centered or striped wick structures leave noncontact container surfaces with the wick structure.In this study,experiments andnumerical analyseswere conductedtoinvestigate the influenceof thesenoncontact surfaces.In the experiments,a strip-shaped wick structure was placed vertically,the top was sandwiched between wider rods and the bottom was immersed in a working fluid.The rod width was greater than the wick width;thus,noncontact surfaces were left between the rod and the wick structure.The heat was applied from the rod to the wick structure,and the evaporation heat transfer characteristics of the working fluid from the wick structure were evaluated.Water was used as the working fluid.The experiments were conducted by varying the rod and wick widths.The experimental results were obtained when the wick structures were placed separately.In the numerical analyses,the temperature and heat flux distributions in the rod were obtained.From the experimental and numerical results,it was confirmed that the noncontact surfaces caused the heat flux in the rod near both surfaces of the wick structure to concentrate,which increased the evaporation thermal resistance of the wick structure.A reduction in the noncontact surface area by increasing the wick width was found to be effective in decreasing the evaporation thermal resistance and increasing themaximumheat transfer rate of the wick structure.The separation of the wick structure increased the evaporation surface area.However,its effectiveness was limited when the heat transfer rate was small. 展开更多
关键词 Ultra-thin heat pipe centered wick structure striped wick structure conduction heat transfer evaporation heat transfer constriction thermal resistance
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Evaporation Heat Transfer Characteristics from a Sintered Powder Wick Structure Sandwiched between Two Solid Walls
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作者 Yasushi Koito Shoma Hitotsuya +1 位作者 Takamitsu Takayama Kenta Hashimoto 《Frontiers in Heat and Mass Transfer》 EI 2023年第1期33-46,共14页
An ultra-thin flattened heat pipe has been developed with a centered wick structure.This structure is essential to make the heat pipe thinner.However,the centered wick structure reduces the evaporation and condensatio... An ultra-thin flattened heat pipe has been developed with a centered wick structure.This structure is essential to make the heat pipe thinner.However,the centered wick structure reduces the evaporation and condensation surface areas of the wick structure because it is sandwiched between heat pipe walls.In this study,because detailed discussion has not been made,heat transfer experiments were conducted for the wick structure sandwiched between two solid walls.This study focused on the evaporation heat transfer characteristics from the sandwiched wick structure.The experiments were conducted with three wick structures,that is,strip-shaped sintered copper powders with thicknesses of 0.5,1.0,and 1.5 mm.Water was used as working fluid.The capillary pumping performance,that is,the liquid lifting velocities of the three wick structures were the same.The experimental results of the three wick structures were compared regarding the relation between the evaporation heat transfer rate and the superheat of the working fluid.The heat transfer experiments were also conducted when one of the solid walls was removed from the wick structure.It was confirmed that even if the wick structure was sandwiched between the solid walls,sufficient evaporation of the working fluid occurred from the thin sides of the wick structure. 展开更多
关键词 Heat transfer ultra-thin heat pipe centered wick structure restricted evaporation surface thermal design electronics cooling
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Structure Improvement and Optimization of Gantry Milling System for Complex Boring and Milling Machining Center
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作者 Zhongxin Zang Qilin Shu 《Journal of Electronic Research and Application》 2023年第5期1-7,共7页
To enhance the efficiency and machining precision of the TX1600G complex boring and milling machining center,a study was conducted on the structure of its gantry milling system.This study aimed to mitigate the influen... To enhance the efficiency and machining precision of the TX1600G complex boring and milling machining center,a study was conducted on the structure of its gantry milling system.This study aimed to mitigate the influence of factors such as structural quality,natural frequency,and stiffness.The approach employed for this investigation involved mechanism topology optimization.To initiate this process,a finite element model of the gantry milling system structure was established.Subsequently,an objective function,comprising strain energy and modal eigenvalues,was synthesized.This objective function was optimized through multi-objective topology optimization,taking into account certain mass fraction constraints and considering various factors,including processing technology.The ultimate goal of this optimization was to create a gantry milling structure that exhibited high levels of dynamic and static stiffness,a superior natural frequency,and reduced mass.To validate the effectiveness of these topology optimization results,a comparison was made between the new and previous structures.The findings of this study serve as a valuable reference for optimizing the structure of other components within the machining center. 展开更多
关键词 Machining center gantry milling system structure Natural frequency STIFFNESS Multi-objective topology optimization
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THE DAVID LAWRENCE CONVENTION CENTER:HOW GREEN BUILDING DESIGN AND OPERATIONS CAN SAVE MONEY,DRIVE LOCAL ECONOMIC OPPORTUNITY,AND TRANSFORM AN INDUSTRY
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作者 Christine Mondor Steve Hockley David Deal 《Journal of Green Building》 2013年第1期28-43,共16页
INTRODUCTION When the David L.Lawrence Convention Center in Pittsburgh was completed in 2003,it was one of largest green buildings in the country.Its success proved that sustainability principles could be integrated i... INTRODUCTION When the David L.Lawrence Convention Center in Pittsburgh was completed in 2003,it was one of largest green buildings in the country.Its success proved that sustainability principles could be integrated into a breathtaking and high-performing design.Using almost a decade of performance data,this study,led by evolveEA,was commissioned to understand the level of building performance and the return on the initial investment in sustainability.With input from Carnegie Mellon University’s Center for Building Performance and Diagnostics,CJL Engineering,and Civil and Environmental Consultants,the Buildings-in-Operation(BiO)study demonstrates that. 展开更多
关键词 high performance design green conventions LEED certified convention center civic structures and urban centers
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MAINTAINABLE MECHANISM OF MESO-β SCALE CONVECTIVE SYSTEM 被引量:1
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作者 彭加毅 伍荣生 王元 《Acta meteorologica Sinica》 SCIE 2002年第4期405-422,共18页
By means of the Penn State-NCAR Mesoscale Model Version 5(MM5)with a horizontal resolution of 20 km.the maintainable mechanism of Meso-β scale Convective System(Mβ CS)has been investigated on the basis of simulation... By means of the Penn State-NCAR Mesoscale Model Version 5(MM5)with a horizontal resolution of 20 km.the maintainable mechanism of Meso-β scale Convective System(Mβ CS)has been investigated on the basis of simulation of the temporal and spatial thermodynamics structure of the MβCS which occurred in Wuhan and its surroundings on 21 July 1998.The occurrence of the significant warm-core in the center of the MβCS happened in Changjiang River Basin between the Mufu Mountain and the Dabie Mountain.To the southern side of the MβCS,there exist the southwest low-level jet(LLJ)and the vertical secondary circulation in the low and middle troposphere respectively.In respect to the northern of the MβCS,the northwest jet emerges in the upper troposphere,accompanied with cold and dry atmosphere downdrafts,resulting in another secondary circulation.The foregoing mentioned vertical wind shear provides a favorable dynamical environment for the intensification and maintenance of the MβCS.Equally important,the latent heat release associated with the MβCS produces the warm center in the middle troposphere and the pressure falls.The pressure drop then accelerates air parcels toward the low leading to strong convergence as well as the intensified convection,establishing a positive feedback between the convection and the latent heat release,which is the thermodynamic mechanism of the development and maintenance of the MβCS. 展开更多
关键词 meso-β scale convective system(MβCS) warm center structure maintainable mechanism
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