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结构参数对微通道换热器内流体分配均匀性的敏感性分析 被引量:4
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作者 袁培 孙冰 +1 位作者 吕彦力 李丹 《轻工学报》 CAS 2016年第3期74-80,共7页
选取换热器微通道的长度、宽度、插入封头的深度作为考察因素,利用均匀设计方法建立模型,对影响微通道换热器内流体流动分配均匀性的敏感性参数进行分析.结果表明:1)微通道换热器流体分配均匀性不仅与流体的流动状态有关系,还与几何... 选取换热器微通道的长度、宽度、插入封头的深度作为考察因素,利用均匀设计方法建立模型,对影响微通道换热器内流体流动分配均匀性的敏感性参数进行分析.结果表明:1)微通道换热器流体分配均匀性不仅与流体的流动状态有关系,还与几何结构有关;保持较低的流速(0.05~0.10 m/s)微通道换热器内流体可获得更好的分配均匀性.2)在入口流速一定的情况下,流体流动分配均匀性是微通道长度、宽度和插入封头深度综合作用的结果.各因素对流体分配均匀性的影响从大到小依次为微通道的宽度、微通道插入封头深度、微通道的长度. 展开更多
关键词 微通道换热器 流体分配均匀 均匀设计 结构参数 敏感因素
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强迫通风在低速大转矩永磁电机上应用分析
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作者 高俊 韩雪岩 +2 位作者 王勇 王世伟 李宏浩 《电机与控制学报》 EI CSCD 北大核心 2022年第11期58-64,共7页
为了解决低速大转矩永磁电机铜损耗大、局部温升过高的问题,以一台630 kW、37.5 r/min的低速大转矩永磁同步电机为研究对象,提出一种风自循环冷却方式,并对其可行性进行了计算分析。首先建立自循环强迫通风计算结构模型和数学模型,并用... 为了解决低速大转矩永磁电机铜损耗大、局部温升过高的问题,以一台630 kW、37.5 r/min的低速大转矩永磁同步电机为研究对象,提出一种风自循环冷却方式,并对其可行性进行了计算分析。首先建立自循环强迫通风计算结构模型和数学模型,并用有限元法确定电机各部分的损耗及生热率;基于流固耦合分析方法对通风孔尺寸进行了优化设计,得到最优通风结构尺寸参数;分析了不同入口风量变化对电机温升的影响规律,同时保证入口风量相同,分析了绕组浸漆和不浸漆状态下的温升规律。在此基础上,为了解决冷却气体分布不均匀导致电机温升分布不均的问题,对机壳与风罩之间的距离进行优化设计,总结了保证气体流动均匀性的方法,为低速大转矩永磁电机的冷却系统设计提供了参考。 展开更多
关键词 低速大转矩 流固耦合 冷却系统 自循环 温度场 流体均匀性
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Evaluation of flow behavior in copper electro-refining cell with different inlet arrangements 被引量:4
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作者 Ping ZHOU Hai-bo MA +2 位作者 Zi-wei XIE Hong-jie YAN Chenn Q. ZHOU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第10期2282-2290,共9页
The arrangement of electrolyte inlet in the copper electro-refining(ER)cell has a great influence on the local flow field,which affects the distribution of electrical current density in consequence.In order to underst... The arrangement of electrolyte inlet in the copper electro-refining(ER)cell has a great influence on the local flow field,which affects the distribution of electrical current density in consequence.In order to understand the complicated phenomena ofelectrolyte flow behavior in vertical counter electrodes in full-scale copper ER cell,the three-dimensional computational fluiddynamics(CFD)models with four different arrangements of electrolyte inlets,i.e.,single inlet(SI),central bottom inlets(CBI),topside interlaced inlets(TII),and bottom side interlaced inlets(BII),were established to simulate the flow behavior.Simulation resultshave revealed that the parallel injection devices help to improve the electrolyte velocity between electrodes,and while the relativerange of electrolyte velocity in CBI exceeds that of TII and BII,which is more than4times,indicating its severer unequal flowdistribution.Meanwhile,the average velocity of electrolyte in BII is4times larger than that of SI due to its higher turbulenceintensity.Generally,one of the efficient ways to supply fresh copper solution rapidly and uniformly into the inter-electrode space is toadapt the arrangement of BII.By utilizing such an arrangement,the electro-refining under high electrical current density is possible,and the productivity can be increased in sequence. 展开更多
关键词 copper electro-refining electrolyte inlet arrangement flow uniformity computational fluid dynamics
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CAP1400非能动堆芯冷却整体试验关键现象分析 被引量:1
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作者 史国宝 徐财红 +2 位作者 严锦泉 樊普 朱升 《原子能科学技术》 EI CAS CSCD 北大核心 2021年第10期1806-1813,共8页
在CAP1400小破口失水事故中,非能动堆芯冷却系统所有设备均投入,显现复杂且独特的物理现象,为验证设计和程序以及识别重要现象,开展了CAP1400非能动堆芯冷却系统性能试验。整体试验台架主要特征为:1∶3高度比、最大工作压力9.2 MPa、等... 在CAP1400小破口失水事故中,非能动堆芯冷却系统所有设备均投入,显现复杂且独特的物理现象,为验证设计和程序以及识别重要现象,开展了CAP1400非能动堆芯冷却系统性能试验。整体试验台架主要特征为:1∶3高度比、最大工作压力9.2 MPa、等压模拟。试验结果表明,在小破口失水事故中堆芯不裸露,试验过程中发现了冷管段分层流产生机制、安注箱排空后氮气注射及其影响以及压力容器下降段流体温度不均匀性等关键物理现象。最后利用RELAP5程序对整体试验关键现象进行了分析和验证。 展开更多
关键词 小破口失水事故 验证试验 冷管段分层流 氮气注射 下降段流体温度不均匀
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Some Magnetized Bulk Viscous String Cosmological Models in Cylindrically Symmetric Inhomogeneous Universe with Variable Λ-Term 被引量:1
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作者 Anirudh Pradhan 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第2期367-374,共8页
Some cylindrically symmetric inhomogeneous viscous fluid string cosmological models with magnetic field and cosmological term A varying with time are investigated. To get the deterministic solution, it has been assume... Some cylindrically symmetric inhomogeneous viscous fluid string cosmological models with magnetic field and cosmological term A varying with time are investigated. To get the deterministic solution, it has been assumed that the expansion (θ) in the model is proportional to the eigen value σ^11 of the shear tensor σ^ij. The value of cosmological constant for the model is found to be small and positive, which is supported by the results from recent supernovae Ia observations. The effect of bulk viscosity is to produce a change in perfect fluid and hence exhibits essential influence on the character of the solution. The physical and geometric properties of the models are also discussed in presence and absence of magnetic field. 展开更多
关键词 STRING inhomogeneous universe cylindrical symmetry variable cosmological term bulk viscosity
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Entropy optimization in cubic autocatalysis chemical reactive flow of Williamson fluid subjected to viscous dissipation and uniform magnetic field 被引量:1
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作者 M. IJAZ KHAN Sania JAVED +2 位作者 Tasawar HAYAT M. WAQAS Ahmed ALSAEDI 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第5期1218-1232,共15页
This research elaborates magnetohydrodynamics (MHD) impact on non-Newtonian (Williamson) fluid flow by stretchable rotating disks.Both disks are rotating with different angular velocities and different stretching rate... This research elaborates magnetohydrodynamics (MHD) impact on non-Newtonian (Williamson) fluid flow by stretchable rotating disks.Both disks are rotating with different angular velocities and different stretching rates.Viscous dissipation aspect is considered for energy expression formulation.Entropy generation analysis is described via implementation of thermodynamic second law.Chemical processes (heterogeneous and homogeneous) subjected to entropy generation are introduced first time in literature.Boundary-layer approach is employed for modeling.Apposite variables are introduced for non-dimensionalization of governing systems.Homotopy procedure yields convergence of solutions subjected to computations of highly nonlinear expressions.The significant characteristics of sundry factors against thermal,velocity and solutal fields are described graphically.Besides,tabular results are addressed for engineering quantities (skin-friction coefficient,Nusselt number).The outcomes certify an increment in temperature distribution for Weissenberg (We) and Eckert (Ec) numbers. 展开更多
关键词 entropy generation viscous dissipation Williamson fluid uniform magnetic felid quartic autocatalysis chemical reaction
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某发动机集成式催化消声器的背压分析及优化
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作者 陈祖荣 赵雄伟 张野华 《轻型汽车技术》 2020年第3期15-19,共5页
汽车排气系统排气背压的直接影响到汽车动力性、燃油经济性及排放性能,通常情况下,背压增大将导致发动机缸内废气排不净、燃烧恶化、燃料燃烧效率下降、经济性变差、动力性下降、排放不达标等问题。排气背压不仅受排气管的大小、长度及... 汽车排气系统排气背压的直接影响到汽车动力性、燃油经济性及排放性能,通常情况下,背压增大将导致发动机缸内废气排不净、燃烧恶化、燃料燃烧效率下降、经济性变差、动力性下降、排放不达标等问题。排气背压不仅受排气管的大小、长度及走向的影响,还受发动机尾气处理装置及消声降噪装置的影响。随着国家对汽车排放要求的提高,发动机排气系统上的尾气处理零部件会越来越多,结构更复杂,排气阻力变大,背压升高。为满足整车及发动机的各项性能指标,本文通过采用流体流动均匀性评价指标λ方法对排气系统的催化消声器进行分析,并经过试验验证,达到降低排气背压的目的。 展开更多
关键词 集成式消声器 排气背压 流体流动均匀
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Hydromagnetic Blood Flow of Sisko Fluid in a Non-uniform Channel Induced by Peristaltic Wave
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作者 A.Zeeshan M.M.Bhatti +1 位作者 N.S.Akbar Y.Sajjad 《Communications in Theoretical Physics》 SCIE CAS CSCD 2017年第7期103-110,共8页
In this paper, a smooth repetitive osciflating wave traveling down the elastic walls of a non-uniform two- dimensional channels is considered. It is assumed that the fluid is electrically conducting and a uniform magn... In this paper, a smooth repetitive osciflating wave traveling down the elastic walls of a non-uniform two- dimensional channels is considered. It is assumed that the fluid is electrically conducting and a uniform magnetic field is perpendicular to flow. The Sisko fluid is grease thick non-Newtonian fluid can be considered equivalent to blood. Taking long wavelength and low Reynolds number, the equations are reduced. The analytical solution of the emerging non-linear differential equation is obtained by employing Homotopy Perturbation Method (HPM). The outcomes for dimensionless flow rate and dimensionless pressure rise have been computed numerically with respect to sundry concerning parameters amplitude ratio , Hartmann number M, and Sisko fluid parameter bl. The behaviors for pressure rise and average friction have been discussed in details and displayed graphically. Numerical and graphical comparison of Newtonian and non-Newtonian has also been evaluated for velocity and pressure rise. It is observed that the magnitude of pressure rise is maximum in the middle of the channel whereas for higher values of fluid parameter it increases. Further, it is also found that the velocity profile shows converse behavior along the walls of the channel against multiple values of fluid parameter. 展开更多
关键词 blood flow peristaltic flow Sisko fluid non-uniform channel
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