检索结果-内蒙古大学图书馆

flow patterns and heat transfer characterization during large aspect ratio hydrogen tank filling

International Journal of Hydrogen Energy 2025年 131卷 26-32页

作者： Couteau, Arthur Dimopoulos Eggenschwiler, Panayotis Jenny, Patrick Chemical Energy Carriers and Vehicle Systems DübendorfCH-8600 Switzerland Institute of Fluid Dynamics ETH Zürich Zürich8092 Switzerland

Temperature management in high-pressure hydrogen tank filling is crucial, requiring detailed analysis of heat transfer physics. This study used 3D CFD simulations to examine how tank aspect ratio, filling time, and orientation affect heat transfer dynamics. Results show that turbulent jet flow extends approximately three tank diameters inward, creating a mixing zone between existing and incoming hydrogen. For tanks shorter than this mixing length, simplified thermodynamic models accurately predict temperature evolution due to uniform gas mixing. Longer tanks exhibit varied flow patterns requiring consideration of multiple heat transfer mechanisms. The present work reveals consistent flow and wall heat flux patterns across different aspect ratios, suggesting potential applications for extending thermodynamic models to diverse tank geometries. These findings contribute to understanding and optimizing high-pressure hydrogen filling processes, with implications for efficient tank design and operation. © 2025 The Authors

关键词： flow patterns

来源：评论

学校读者我要写书评

暂无评论

A new frictional pressure drop correlation based on flow patterns for hydrocarbon refrigerants condensation flow

引用

INTERNATIONAL JOURNAL OF REFRIGERATION 2025年 170卷 214-223页

作者： Fang, Xianshi Qiu, Guodong Chen, Jie Liu, Kexin Li, Qian Cai, Weihua Northeast Elect Power Univ Sch Energy & Power Engn Lab Thermo fluid Sci & Nucl Engn Jilin 132012 Peoples R China CNOOC Gas & Power Grp Beijing 100027 Peoples R China Shenyang Polytech Coll Shenyang 110045 Peoples R China

Accurately predicting frictional pressure drop of hydrocarbon refrigerants during condensation is crucial for the efficient design of heat exchangers. Currently, various correlations exist for predicting this pressure drop for hydrocarbon refrigerants. The differences in prediction accuracy among these correlations for the same working fluid significantly increase the uncertainty in heat exchangers design. This paper evaluates eight commonly used and different development forms of frictional pressure drop correlations based on experimental data of pure and mixed hydrocarbon refrigerants. The results indicate that the universality of existing correlations needs improvement. Additionally, from a mechanistic perspective, a flow-pattern-based calculation method for frictional pressure drop in condensation flow is proposed. The predictive accuracy and universality of the proposed correlation are verified with methane, ethane, propane, and methane/propane mixed refrigerants. Specifically, 79.57 % of the predicted results exhibit deviations from experimental data within 20 %, while 92.4 % show deviations within 30 %. The Mean Relative Deviation (MRD) is 0.75 %, while the Mean Absolute Relative Deviation (MARD) stands at 12.98 %. The frictional pressure drop correlation developed in this study demonstrates high precision and broad applicability. The continuity of the correlation is ensured through the incorporation of the meniscus angle, making it highly suitable for improving the design of relevant condensation heat exchangers.

关键词： Hydrocarbon refrigerants Condensation Frictional pressure drop flow patterns Correlations

来源：评论

学校读者我要写书评

暂无评论

Influence of a 'Step' on the liquid-liquid flow patterns and flow phenomena in a microfluidic Y-Y channel

引用

CHEMICAL ENGINEERING JOURNAL 2025年 512卷

作者： Sudha, Anand Santoso, Albert Rohde, Martin Delft Univ Technol Dept Radiat Sci & Technol Mekelweg 5 NL-2628 CD Delft Netherlands Delft Univ Technol Dept Chem Engn Maasweg 9 NL-2629 HZ Delft Netherlands

Microfluidic multiphase flows are being increasingly used in many mass transfer applications because of the numerous advantages of operating in the microscale such as greater flow stability and low cost. Among the various flow regimes, parallel flow in the microscale is considered to be advantageous for extraction applications, especially radioisotope transfer, because efficient transfer and purification are possible as long as the interface position remains stable throughout without leakage at the outlets. Therefore, some papers have worked with asymmetric microchannels with different depths for the two fluids in mass transfer applications. The flow phenomena in such channels, however, have not been studied in detail. This paper focuses on these asymmetric microchannels, which we have termed 'step' channels, and the influence such an asymmetry has on the flow phenomena. We perform experiments on this channel and compare the flow maps with experiments in a channel of uniform depth (standard channel). The step channel was found to favour parallel flow and interestingly, to produce stable parallel flow without leakage at low Capillary numbers. This is contrary to the results observed in a standard channel, where slug flow is observed. Volume-of-fluid simulations showed the role of interfacial tension in obtaining stable parallel flow in a step channel. Additionally, flow maps were also plotted for step channels of different widths and degrees of asymmetry, where it was found that smaller widths and higher degrees of asymmetry favour stable parallel flow.

关键词： Microfluidics Multiphase flow Liquid-liquid extraction flow maps flow separation flow patterns

来源：评论

学校读者我要写书评

暂无评论

Identification of flow patterns in an opaque condenser tube by distributed fiber Bragg gratings

引用

APPLIED THERMAL ENGINEERING 2025年 258卷

作者： Wang, Haoqi Wen, Shizhe He, Zhenhui Sun Yat Sen Univ Sch Phys & Astron Zhuhai 519082 Peoples R China

Two-phase loops with phase change heat transfer are pivotal for cooling electronics under high heat flux and for thermal control in spacecraft. Numerous studies aim to clarify the mechanisms behind these loops to enhance cooling capacity and stability, which are closely tied to flow patterns. However, conventional flow pattern identification methods, requiring transparent tubes for direct observation, are impractical for simultaneous heat transfer measurement, especially during condensation. This paper introduces a novel approach for identifying flow patterns within an opaque, vertical condensation tube using embedded distributed fiber Bragg gratings (DFBGs) for R134a. The method involves a "fingerprint" derived from temperature profile derivatives and additional criteria based on temperature variation characteristics. These include the relative deviation from saturation temperature, the relative spatial temperature gradients, and the relative amplitude of temperature fluctuations. Validation against high-speed camera images confirms the method's efficacy. It enables the determination of flow pattern lengths, the endpoint of condensation, and the construction of a flow regime map. Additionally, it allows for the measurement of vapor velocity in slug flow, facilitating the calculation of slip ratio and void fraction, which correlates reasonably with the Zuber-Findlay model, with systematic positive deviations up to 30%. This method also paves the way for simultaneous measurement of in-tube condensation heat transfer characteristics for various flow patterns.

关键词： flow patterns Identification Temperature profile characteristics Distributed fiber Bragg gratings Slip ratio Void fraction flow regime map

来源：评论

学校读者我要写书评

暂无评论

Experimental visualization of dry regions formation for Falling-Film flow patterns

引用

INTERNATIONAL JOURNAL OF HEAT AND FLUID flow 2025年 114卷

作者： Kandukuri, Prudviraj Deshmukh, Sandip Katiresan, Supradeepan Birla Inst Technol & Sci Dept Mech Engn Hyderabad Campus Hyderabad India

Water is essential for humans in everyday life, and plenty of fresh water is required for agricultural, chemical, industrial, and other domestic uses. Water scarcity is becoming increasingly prevalent in many regions and countries as they advance their respective growth lines. The predominant method employed in thermal desalination plants is the falling-film process due to its operational advantages. The present study examines the mapping of diverse flow patterns for heat transfer mechanisms across the horizontal tube bundle. An experimental test facility is developed, and a series of visualization experiments are conducted. The FLIR E60 infrared camera is employed to examine the liquid film behavior for different temperature profiles. The findings revealed that the droplet flow pattern induces wave-like wetting, whereas the column flow pattern induces liquid ring wetting on the tube wall. The tube wall temperature attains its maximum during droplet flow, regardless of the chosen tube spacing values. When the tube spacing is 10/20/30/40 mm, the maximum temperature of the liquid film is reached rapidly in the droplet flow, reaching values of 75.7 degrees C, 73 degrees C, 79.1 degrees C, 65.8 degrees C, 76.5 degrees C, 71.4 degrees C, 69.3 degrees C, and 74.2 degrees C, respectively, in comparison to other flow modes. The infrared photographic images show that the stabilizing tube has a faster heat transfer mechanism than the test tube. Furthermore, the liquid profile on the upper portion of the tube wall exhibits a faster evaporation rate than the lower one. The formation of dry spots on the test tubes and stabilizing tubes exhibited a distinct pattern due to distinct flow mode wetting phenomena for chosen working conditions. The research findings address various aspects of information on falling-film flow behavior and mapping of flow patterns to heat transfer mechanisms.

关键词： Desalination Dry regions Falling-film flow patterns Heat transfer mechanism

来源：评论

学校读者我要写书评

暂无评论

A hybrid study of micro-plastics flow patterns in rivers 12th

A hybrid study of micro-plastics flow patterns in rivers

引用

12th International Conference on Fluvial Hydraulics, River flow 2024

作者： Carvalho, R.F. Restrepo, S. Ferreira, R.M.L. Dep. Civil Engineering University of Coimbra MARE-Marine and Environmental Research Centre ARNET-Aquatic Research Network Coimbra Portugal CERIS-Instituto Superior Técnico Universidade de Lisboa Lisbon Portugal

ISBN: (纸本)9781032757216

In this work, a numerical solution of the flow in a flume with a single lateral cavity, forming a semi-enclosed volume adjacent to the main channel, is presented. Additionally, different areas of particles injection, mimicking micro-plastics released in the flow, are investigated. The numerical models are based on the deterministic description of hydrodynamics using an Eulerian-Lagrangian approach and numerical closure models within OpenFOAM®. A Lagrangian solver is applied to describe different particles injected in different areas, their transport and deposit, particularly in the neighborhood of the transition of the main flow with single lateral cavity, where important exchanges occur. Results of the flow patterns are compared with measurements and images acquired within a PIV system on the physical model, and different particles injection areas were analysed to evaluate lateral cavity retention. Different places of injection inside the cavity lead to different deposition areas. Injection inside the cavity closer to downstream edge and to free-surface lead to higher dispersion out of the cavity. © 2025 The Author(s).

关键词： flow patterns

来源：评论

学校读者我要写书评

暂无评论

Study on induced flow patterns and inlet velocity in inclined tunnel fire with natural ventilation

引用

TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY 2025年 155卷

作者： Chen, Xiaofeng Li, Jiangdong Ni, Yiling Liang, Zhirong Ding, Hangqiang Liu, Lei Zhang, Xin Wu, Ke Zhang, Tianhang Zhejiang Univ Key Lab Offshore Geotech & Mat Zhejiang Prov Hangzhou 310058 Peoples R China Zhejiang Univ Ctr Balance Architecture Hangzhou 310058 Peoples R China Zhejiang Univ Res Ctr Urban Fire Safety Engn Hangzhou 310058 Zhejiang Peoples R China Hangzhou Fuyang City Construct Investment Grp Co L Hangzhou 311499 Peoples R China Beihang Univ Hangzhou Int Innovat Inst Hangzhou 311115 Peoples R China Urban Infrastruct Construct Co LTD Hangzhou Fuyang Urban Construct Grp Hangzhou 311499 Peoples R China Xian Shiyou Univ Coll Elect Engn Xian 710065 Peoples R China

Inclined tunnels serve as a vital role in modern urban transportation networks. Nevertheless, the height-induced stack effect caused by the tunnel inclination during tunnel fires, results in smoke movement with multidirectional flow patterns, thus making the smoke flow in a very complicated manner. This study investigates the inlet ventilation velocity with flow field characteristics analysis for inclined tunnel fires under natural ventilation. Three flow patterns (i.e. "bidirectional flow", "transitional flow", and "unidirectional flow") are clearly identified according to different airflow directions and smoke stratification. Moreover, theoretical analysis reveals that the flow patterns are principally governed by the interactive effects of thermal buoyancy (or fire HRR) and inertia forces (or induced velocity) concurrently. Herein, a modified Richardson number Ri ', which essentially reflects the ratio of buoyant effect to inertial effect, has been proposed to determine the flow patterns in the inclined tunnel fires. Specifically, when Ri ' < 1.91, the airflow inertia force dominates the flow field structure, which causes the fire smoke to be a unidirectional flow with the longitudinal ventilation flow, and thus forms well-mixed gas. As Ri ' increases, the buoyant effect becomes more prominent, which triggers the intermittent mixing regime occurred with fire smoke in induces a transitional flow state and partial stratification. When Ri ' increases to 17.57, the buoyancy is predominant and leads the fire smoke to be complete stratification. In this case, the fire smoke and entrained air flow in opposite directions, resulting in a bidirectional flow within the tunnel. In addition, it is found that the inlet ventilation velocity increases with the increase of slope or tunnel length, but remains relatively unchanged by their combined influence under a fixed absolute tunnel height difference. Finally, considering the stratification characteristic in three flow pattern

关键词： Tunnel fire Natural ventilation flow patterns Stack effect Modified Richardson number

来源：评论

学校读者我要写书评

暂无评论

Mathematical Study of Partial Blockage of SEN in Specific Zones on flow patterns in the Mold

Mathematical Study of Partial Blockage of SEN in Specific Zo...

引用

154th Annual Meeting and Exhibition of The Minerals, Metals and Materials Society, TMS 2025

作者： González, Marbella Durán Gutiérrez, Enif Garcia-Hernandez, Saul Cabrera, Eriwiht D. Tello TecNM-Instituto Tecnologico de Morelia Metallurgy Graduate Center Michoacán Morelia Mexico

ISBN: (纸本)9783031807473

Most studies on nozzle clogging simplify their analysis by using symmetric reductions to simulate the clogging. However, this approach overlooks that clogging typically occurs asymmetrically, leading to a significant increase in the roughness of the inner wall of the nozzle. Therefore, this work aims to compare the results obtained using the usual symmetric simplifications with those obtained from a nozzle at the end of its industrial use. The industrial nozzle at the end of its use has been 3D scanned and shows significant geometric reductions in the lower tubular area, the ports, and the pool. The results obtained show that any nozzle reductions have a direct impact on the mold flow patterns. In addition, it was demonstrated that symmetrical reductions are not enough to accurately reproduce the fluid dynamics within the nozzle and mold, as nozzle irregularities strongly influence the meniscus stability. © TheMinerals, Metals & Materials Society 2025.

关键词： flow patterns

来源：评论

学校读者我要写书评

暂无评论

flow patterns and deformation modes of coaxial liquid columns in transverse electric fields

引用

EUROPEAN PHYSICAL JOURNAL E 2013年第10期36卷 1-23页

作者： Behjatian, Ali Esmaeeli, Asghar So Illinois Univ Dept Mech Engn & Energy Proc Carbondale IL 62901 USA

Steady-state flow patterns and deformation modes of coaxial liquid columns in transverse electric fields are studied analytically. The governing creeping flow equations are solved for Newtonian and (mutually) immiscible fluids in the framework of leaky dielectric theory. A detailed analysis of the electric and flow fields is presented and it is shown that there will be four possible flow patterns in and around the columns, in terms of the direction of the external flow (top-to-sides/bottom-to-sides vs. sides-to-top/sides-to-bottom) and the number of vortices (single vortex vs. double vortices) in the shell, and that the senses of the net electric shear stresses at the inner and the outer interfaces and their relative importance are the key parameters in setting these patterns. Equilibrium shapes of the interfaces are also found and it is shown that there are four distinct modes of deformation, depending on the governing nondimensional parameters of the problem. The instability of the jet is also examined qualitatively using the observations pertaining the instability of single-phase drops and jets and the scaling arguments based on the present solution.

关键词： deformation transverse Steady-state Transverse senses deformation pattern Interfaces flow patterns vortices deformation jets transverse electric Coaxial Electricity Steady state transverse magnetic field Interface

来源：评论

学校读者我要写书评

暂无评论

flow patterns and energy dissipation over various stepped chutes

引用

JOURNAL OF IRRIGATION AND DRAINAGE ENGINEERING 2006年第1期132卷 70-76页

作者： Chinnarasri, C Wongwises, S King Mongkuts Univ Technol Thonburi Dept Civil Engn Water Resources Engn Res Lab WAREE Bangkok 10140 Thailand King Mongkuts Univ Technol Thonburi Dept Mech Engn Fluid Mech Thermal Engn & Multiphase Flow Res Lab FUTURE Bangkok 10140 Thailand

To reduce the size of the dissipation basin, the stepped chute has been accepted to be the most powerful hydraulic structure to dissipate large flow energy downstream from steep hills. This paper presents the flow characteristics and factors for energy dissipation in various types of stepped chutes: horizontal steps, inclined steps, and steps with end sills. Delineated and descript flow regimes are observed. The relationships between relative energy loss and relative critical flow depth on three stepped chutes are presented and discussed. The steps with end sills seem to be the most efficient configuration in terms of relative energy dissipation. The effect of number of steps is evident since the relative energy loss increases with the number of steps. In addition, new correlations showing the relation between relative energy loss and relative critical flow depth are proposed for practical applications.

关键词： flow patterns energy dissipation laboratory tests

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：