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PEM燃料电池阴极侧分流式流道研究
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作者 徐康 方存光 《内燃机与配件》 2024年第13期34-36,共3页
流道是PEM燃料电池里面负责反应物运输和产物排除的场所,因此流道结构对PEM膜燃料电池性能有重要影响。因为阳极通的是纯氢气,氢气扩散系数较大。阳极不会出现氢气量满足不了反应需要的情况,所以本文不研究阳极的反应情况。阴极侧是主... 流道是PEM燃料电池里面负责反应物运输和产物排除的场所,因此流道结构对PEM膜燃料电池性能有重要影响。因为阳极通的是纯氢气,氢气扩散系数较大。阳极不会出现氢气量满足不了反应需要的情况,所以本文不研究阳极的反应情况。阴极侧是主要的反应场所,阴极侧流道需要让尽可能多的氧气参与反应同时要有更好的排水能力。基于传统流道的研究现状,设计了1种分流式的阴极侧流道。利用多物理场耦合软件COMSOL对新型流道做了数值模拟和分析比较。结果表明:与传统直流道相比,阴极侧采用分流式流道设计的燃料电池比阴极侧采用传统直流道设计的燃料电池能提供更大质量分数更均匀的氧气分布、减少水的质量分数、更均匀的电流密度分布。 展开更多
关键词 PEM燃料电池 流道 分流流道 电流密度
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分流式热量表流道模型
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作者 赵光霞 徐坤 陈风明 《排灌机械工程学报》 EI CSCD 北大核心 2017年第12期1058-1062,共5页
针对一种新型的分流式热量表的结构模型,采用了RNG的流体湍流模型,建立了偏心流道不同开度大小和不同偏离角度的数学模型,通过Fluent仿真软件,分析了这种分流式热量表的分流结构以及内部流体的运动特性,并针对试验中模拟的分流式流道模... 针对一种新型的分流式热量表的结构模型,采用了RNG的流体湍流模型,建立了偏心流道不同开度大小和不同偏离角度的数学模型,通过Fluent仿真软件,分析了这种分流式热量表的分流结构以及内部流体的运动特性,并针对试验中模拟的分流式流道模型,采用流体动力学计算方法,对分流式流道结构优化后不同宽度流道流场进行了数值模拟和分析计算.模拟结果表现出了分流式流道内流体的湍流特性,同时研究分析表明了分流式流道与叶轮叶片呈一定角度时,水流可以较好地增强叶轮叶片的作用力.通过对分流式流道开口大小、偏离角度的优化等研究,为提高分流式热量表的测量精确度提供了良好的理论基础. 展开更多
关键词 分流式热量表 分流流道模型 流道 流场 数值模拟
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丙烯腈急冷塔喷淋系统流道分析与优化 被引量:3
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作者 刘文杰 《石化技术与应用》 CAS 2003年第6期431-435,共5页
对国内现有丙烯腈装置急冷塔循环液喷淋器的分流流道进行了研究。对喷头堵塞情况作了理论分析 ,并运用计算机编程模拟计算出喷淋器中各喷头的流体分布情况。在此基础上提出了分流流道的优化方案 ,从而改善了急冷塔内的操作状况 ,减少了... 对国内现有丙烯腈装置急冷塔循环液喷淋器的分流流道进行了研究。对喷头堵塞情况作了理论分析 ,并运用计算机编程模拟计算出喷淋器中各喷头的流体分布情况。在此基础上提出了分流流道的优化方案 ,从而改善了急冷塔内的操作状况 ,减少了丙烯腈在急冷塔内的损失。 展开更多
关键词 丙烯腈 急冷塔 分流流道 循环液喷淋器 优化
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分流流道内流动结构的测试与分析 被引量:3
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作者 薛翔 王彤 《工程热物理学报》 EI CAS CSCD 北大核心 2017年第3期529-534,共6页
分叉管道常见于工程上的流量分配装置、飞行器内外涵道结构,其中分流流道的流动结构影响着主流道的通流量,且回流涡的产生与扩大会引起分流流道的阻塞,使之失去分流的作用。本文采用高速摄影对分流流道内部的流动结构进行识别,发现在其... 分叉管道常见于工程上的流量分配装置、飞行器内外涵道结构,其中分流流道的流动结构影响着主流道的通流量,且回流涡的产生与扩大会引起分流流道的阻塞,使之失去分流的作用。本文采用高速摄影对分流流道内部的流动结构进行识别,发现在其入口处存在明显的回流涡,进而对回流涡处壁面进行了压力动态测量。压力动态测试与高速摄影的结果显示出分流通道中回流涡流场变化的频率信息。在不同的管道入口雷诺数(Re_(in)=80249到179414)下,回流涡处的壁面压力变化具有混沌特性,随着入口雷诺数的增加,压力脉动的幅值增大,而随机性却减小,确定性和稳定性增强,且在回流涡产生位置尤为显著,影响整个分流流道的通流能力。 展开更多
关键词 分流流道 回流涡 高速摄影 压力动态测量
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模块通液液冷试验样机设计研究
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作者 刘洋 邓荃予 +2 位作者 王成前 陈於杰 马翱强 《电信技术研究》 2017年第2期40-45,共6页
随着电子设备小型化、模块化、高集成化发展,芯片热流密度越来越高,而数量众多的大发热器件均采用模块方式集中安装,散热问题更显突出.因此传统的散热方式已渐渐无法满足新系统的使用要求。本文根据现有CPCI机箱的装配特点和热控需... 随着电子设备小型化、模块化、高集成化发展,芯片热流密度越来越高,而数量众多的大发热器件均采用模块方式集中安装,散热问题更显突出.因此传统的散热方式已渐渐无法满足新系统的使用要求。本文根据现有CPCI机箱的装配特点和热控需求,设计出一款基于液冷的CPCI加固机试验样机并搭建试验测试平台,对样机在不同功耗、供液流量条件下的散热性能进行实验测试,收集了切实可靠的基础试验数据。摸清了液冷散热的各项参数及性能,从而推动新一代加固计算机的性能提高.为后续液冷工程化应用提供了可行的参考。 展开更多
关键词 液冷散热 液冷机箱 流道分流 液冷模块 测试系统
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Experimental Research on Gas-Liquid Two-Phase Spiral Flow in Horizontal Pipe 被引量:8
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作者 Wang Shuli Rao Yongchao +1 位作者 Wu Yuxian Wang Xiaobing 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2012年第3期24-32,共9页
In view of the importance of gas-liquid two-phase spiral flow and the few research reports at home and abroad,the gas-liquid two-phase spiral flow patterns have been researched in a horizontal pipe with different para... In view of the importance of gas-liquid two-phase spiral flow and the few research reports at home and abroad,the gas-liquid two-phase spiral flow patterns have been researched in a horizontal pipe with different parameters investigated by means of observation and a high-speed camera.Since the appearance of spiral flow makes the distribution of twophase flow more complicated,the flow patterns appearing in the experiments were divided into the Spiral Wavy Stratified Flow(SWS),the Spiral Bubble Flow(SB),the Spiral Slug Flow(SS),the Spiral Linear Flow(SL),the Spiral Axial Flow(SA),and the Spiral Dispersed Flow(SD) by the observations and with reference to the predecessors' research achievements.A flow pattern map has been drawn up.The influence of velocity,vane angle and vane area on flow pattern conversion boundary and pressure drop has been studied,with a solid foundation laid for the future research work. 展开更多
关键词 gas-liquid two-phase spiral flow VANE flow pattern flow pattern map experimental research
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New technique for preparing A356 alloy semisolid slurry and its rheo-diecast microstructure and properties 被引量:9
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作者 Ming-fan QI Yong-lin KANG +2 位作者 Yu-zhao XU Jing-yuan LI Ai-sen LIU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2021年第7期1868-1884,共17页
A new technique for preparing semisolid slurry,namely,distributary-confluence runner(DCR),was combined with die-casting(DC)to conduct rheological die-casting(R-DC)of A356 alloy.The mechanism of DCR for semisolid slurr... A new technique for preparing semisolid slurry,namely,distributary-confluence runner(DCR),was combined with die-casting(DC)to conduct rheological die-casting(R-DC)of A356 alloy.The mechanism of DCR for semisolid slurry preparation was determined via numerical simulations and experiments.The microstructure and mechanical properties of A356 alloys prepared via DC and R-DC were studied.High-quality slurry containing numerous primary α-Al(α1-Al)with an average size of 49μm and a shape factor of 0.81 could be prepared via DCR.Simulation results indicated that the unique flow state and physical field changes during slurry preparation were conducive to accelerating the uniformity of melt temperature and composition fields,nucleation exfoliation,and spherical growth.Compared with the alloy prepared via DC,the tensile strength,yield strength,and elongation of A356 alloy prepared via R-DC increased by 19%,15%,and 107%,respectively. 展开更多
关键词 semisolid slurry A356 alloy distributary-confluence runner rheological die-casting microstructure tensile properties
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80上亮框异型材模具机头设计
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作者 刘军 《塑料工业》 CAS CSCD 北大核心 2007年第B06期224-225,228,共3页
以异型材机头的模具设计技术和CAD/CAM计算机软件应用技术为理论基础,对塑料异型材80上亮框挤出模具机头的设计进行了深入的探讨和研究。对其中内筋和薄壁处的设计提出了一些独特的观点。
关键词 挤出模具 分流流道
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异型材模具设计
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作者 李永宏 《模具工程》 2010年第6期73-74,78,共3页
本文以异型材机头的模具设计技术和CAD/CAM计算机软件应用技术为理论基础,对塑料异型材60上亮框挤出模具机头的设计进行了深入的探讨和研究,对其中内筋和薄壁处的设计提出了一些独特的观点。
关键词 挤出模具 分流流道
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Temperature Profiles in the Flow Channel of a Natural Convection Solar Air Heater
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作者 K.S. Ong B.T. Tan 《Journal of Energy and Power Engineering》 2011年第2期129-134,共6页
An experimental investigation was conducted to measure the temperature variation across the flow channel and to determine the performance of a natural convection solar air heater at various tilt angles from 15, 30 and... An experimental investigation was conducted to measure the temperature variation across the flow channel and to determine the performance of a natural convection solar air heater at various tilt angles from 15, 30 and 45°. The results of the temperature profile across the air gap showed that heat transfer from the absorber plate to the air stream was mainly by convection. At a particular section, mean air temperature could be calculated from the arithmetic mean of the temperature profile across the air gap to within ± 2 ℃. The axial air temperature distribution was non linear and did not increase much beyond 1 m of collector length. It tended to decrease towards the end of the collector. Overall glass, absorber plate and mean air temperatures over the entire length of the solar air heater could be determined by averaging the mean axial temperatures to within ± 2 ℃. The heater performed better as inclination increased. 展开更多
关键词 Solar air heater natural convection inclination effects temperature profile across air gap axial temperature distribution.
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Numerical investigation on synthetic jet flow control inside an S-inlet duct 被引量:7
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作者 CHEN ZhanJun WANG JinJun 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第9期2578-2584,共7页
The high degree of centerline curvature and cross-stream pressure gradient in S-inlet ducts gives rise to boundary layer separation and secondary flows, which result in poor pressure recovery and non-uniform flow in t... The high degree of centerline curvature and cross-stream pressure gradient in S-inlet ducts gives rise to boundary layer separation and secondary flows, which result in poor pressure recovery and non-uniform flow in the outlet interface with the engine. The flowfield in ducts is three-dimensional due to the existence of secondary flow, so ordinary two-dimensional actuations have poor effect on reforming the flow. Synthetic jet actuations extended in different spanwise positions were employed to manipulate the flow, and compared with the two-dimensional actuation, The interaction mechanics between flow separation and secondary flow was studied at first. It was found that the secondary flow enhanced Ol~ weakened flow separation depending on the spanwise position of synthetic jet actuators. Moreover, the J flow separation enhanced the secondary flow, thus causing lower pressure recovery and flow distortion in the duct outlet. The actuators located at different spanwise positions will weaken the secondary flows by improving the flow separation to get energetic and uniform main flow. 展开更多
关键词 S-inlet duct synthetic jet flow control pressure RECOVERY swirl flow
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Secondary Flow Effects in Relatively Narrow Channels 被引量:1
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作者 Rudolf Dvo■ák 《Journal of Thermal Science》 SCIE EI CAS CSCD 2003年第3期209-213,238,共6页
Secondary flow effects were discussed in numerous papers at the past ISAIF Symposia, mainly in connection with turbine or compressor cascades. This paper will complement these papers by looking at the problem from the... Secondary flow effects were discussed in numerous papers at the past ISAIF Symposia, mainly in connection with turbine or compressor cascades. This paper will complement these papers by looking at the problem from the channel (or blade passages) geometry point of view. If we describe as secondary flows any flows in planes perpendicular to the main flow direction, then there are at least three kinds of secondary flows in a typical turbine rotor cascade:-secondary flows of the 1st kind, generated by centrifugal forces in closed curved channels,-secondary flows of the 2nd kind, generated by interacting boundary layers, mainly in corners (this will include even the horseshoe vortices),-secondary flows due to mass inflow through the tip clearance.Quite often all the secondary flow vortices merge downstream into a passage vortex with a non-negligible contribution to the channel (cascade) losses, and it is worth investigating the individual contributions to these losses to take them into account in the design procedure. 展开更多
关键词 channel flows secondary flows flow separation.
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Analysis of Turbulent Heat Transfer and Fluid Flow in Channels with Various Ribbed Internal Surfaces 被引量:1
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作者 Smith Eiamsa-ard Wayo Changcharoen 《Journal of Thermal Science》 SCIE EI CAS CSCD 2011年第3期260-267,共8页
This paper presents results of a numerical investigation of heat transfer and flow pattern characteristics of a channel with repeated ribs on one broad wall. Numerical computations are performed for seven ribs placed ... This paper presents results of a numerical investigation of heat transfer and flow pattern characteristics of a channel with repeated ribs on one broad wall. Numerical computations are performed for seven ribs placed on the bottom wall of a channel for Reynolds numbers ranging from 10,000 to 30,000. The newly modified ribs (the ones with convex pointing upstream/downstream rib, wedge pointing upstream/downstream rib, concave pointing upstream/downstream rib and also concave-concave rib as well as convex-concave rib), are proposed for simulation with prospect to reduce flow separation and extend reattachment area compared to the unmodified square rib. The numerical results are reported in forms of flow structure, temperature field, turbulent kinetic energy, Nusselt number, friction factor and thermal enhancement factor. The results indicate the rib with concave-concave surfaces efficiently suppresses flow separation bubble in the corner of the rib and induces large recirculation zone over those of the others, hence giving the highest Nusselt number and friction factor. On the other hand, the one with convex-concave surface provides the lowest friction factor with moderate Nusselt number. Due to the prominent effect of its low friction factor, the rib with convex-concave surface offers the highest thermal enhancement factor of 1.19. 展开更多
关键词 RIB Turbulent flow Heat transfer Reattachment zone Flow separation
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Theoretical and Computational Analyses of LNG Evaporator 被引量:1
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作者 Palani Kumar Chidambaram Yang Myung Jo Heuy Dong Kim 《Journal of Thermal Science》 SCIE EI CAS CSCD 2017年第2期132-137,共6页
Theoretical and numerical analysis on the fluid flow and heat transfer inside a LNG evaporator is conducted in this work. Methane is used instead of LNG as the operating fluid. This is because; methane constitutes ove... Theoretical and numerical analysis on the fluid flow and heat transfer inside a LNG evaporator is conducted in this work. Methane is used instead of LNG as the operating fluid. This is because; methane constitutes over 80% of natural gas. The analytical calculations are performed using simple mass and energy balance equations. The analytical calculations are made to assess the pressure and temperature variations in the steam tube. Multiphase numerical simulations are performed by solving the governing equations(basic flow equations of continuity, momentum and energy equations) in a portion of the evaporator domain consisting of a single steam pipe. The flow equations are solved along with equations of species transport. Multiphase modeling is incorporated using VOF method. Liquid methane is the primary phase. It vaporizes into the secondary phase gaseous methane. Steam is another secondary phase which flows through the heating coils. Turbulence is modeled by a two equation turbulence model. Both the theoretical and numerical predictions are seen to match well with each other. Further parametric studies are planned based on the current research. 展开更多
关键词 LNG Evaporator Analytical Calculation Numerical Simulation
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Convective heat transfer analysis for MHD peristaltic flow in an asymmetric channel 被引量:1
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作者 M. Awais S. Farooq +2 位作者 H. Yasmin T. Hayatt A. Alsaedi 《International Journal of Biomathematics》 2014年第3期1-15,共15页
Magnetohydrodynamic peristaltic flow of Jeffery fluid in an asymmetric channel is addressed. The channel walls satisfy the convective conditions. Asymmetry here is con- sidered due to wave trains of different amplitud... Magnetohydrodynamic peristaltic flow of Jeffery fluid in an asymmetric channel is addressed. The channel walls satisfy the convective conditions. Asymmetry here is con- sidered due to wave trains of different amplitudes and phases. Solutions for the velocity, temperature and pressure gradient are obtained using long wavelength approximation. Plots reflecting the impact of various parameters of interest are shown and examined. 展开更多
关键词 Jeffery fluid convective boundary conditions pumping and trapping.
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Effects of heat transfer on the peristaltic MHD flow of a Bingham fluid through a porous medium in a channel 被引量:2
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作者 V. P. Rathod D. Laxmi 《International Journal of Biomathematics》 2014年第6期1-20,共20页
In this paper, we study the effects of heat transfer on the peristaltic magneto- hydrodynamic (MHD) flow of a Bingham fluid through a porous medium in a channel. Long wavelength approximation (that is, the waveleng... In this paper, we study the effects of heat transfer on the peristaltic magneto- hydrodynamic (MHD) flow of a Bingham fluid through a porous medium in a channel. Long wavelength approximation (that is, the wavelength of the peristaltic wave is large in comparison with the radius of the channel) and low Reynolds number are used to linearize the governing equations. The velocity field for the model of interest is solved by Adomian decomposition method. The expressions for pressure rise, flow rate and frictional force are obtained. The effect of magnetic field, Darcy number, yield stress, amplitude ratio and the temperature on the axial pressure gradient, pumping charac- teristics and frictional force are discussed through graphs. 展开更多
关键词 Bingham fluid yield stress peristaltic flow magneto-hydrodynamic fluid heat transfer analysis Adomian decomposition method.
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