Journal of fluid flow, heat and mass transfer最新文献_第5页

Unlocking the Future with Flexible, Wire-Shaped Supercapacitors 用柔韧的线状超级电容器开启未来

Journal of fluid flow, heat and mass transfer Pub Date : 2021-01-01 DOI: 10.11159/jffhmt.2021.025

J. Sleppy, Alisa Silverstein, Deon Moser

引用次数: 1

Numerical Analysis of Enhanced Heat Transfer Using a Pair of Similar Porous Baffles in a Backward-Facing Step Flow 后向阶跃流动中一对类似多孔挡板强化换热的数值分析

Journal of fluid flow, heat and mass transfer Pub Date : 2021-01-01 DOI: 10.11159/jffhmt.2021.024

J. Arthur, Owen Schiele

{"title":"Numerical Analysis of Enhanced Heat Transfer Using a Pair of Similar Porous Baffles in a Backward-Facing Step Flow","authors":"J. Arthur, Owen Schiele","doi":"10.11159/jffhmt.2021.024","DOIUrl":"https://doi.org/10.11159/jffhmt.2021.024","url":null,"abstract":"Baffles have long been known to be useful in enhancing heat transfer in channels with sudden expansions. However, their utility has been limited due to the increased differential pressure they incur in the flow. In this work, a pair of porous baffles is proposed to provide a solution to this problem. It is based on a finite-element numerical simulation of heat transfer and fluid flow through a two-dimensional channel with a backward-facing step. The baffles are modelled as matrices of two-dimensional rods arrayed downstream of the step, and on the top and bottom walls of the channel. Nondimensionalized parameters considered are the Reynolds number, Re (= 100 to 1000), normalized porous matrix location xp/S (= 0.5 to 6), normalized porous block length Lp/S (= 0.5 to 2.5), Darcy Number, Da (= 10-2 to 10-6), and normalized channel downstream length Ld/S (= 5 to 30). Results show that compared to the case of an unobstructed channel, the installation of porous baffles on both channel walls can generate up to 200% improvement in heat transfer. Optimal heat transfer effect with minimal differential power requirement is attained when the porous baffle length is half the step height S, and located 2S downstream from the step. Augmented heat transfer outcomes with minimal penalty of pressure drop are also reached at Re = 1000 and for Lu /H = 5. For such a case, for the same pressure drop requirement, convection to conduction heat transfer is 88% better when a pair of porous baffles are used, compared to an unobstructed flow.","PeriodicalId":92806,"journal":{"name":"Journal of fluid flow, heat and mass transfer","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84670592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Numerical Solution of Laminar Flow over Symmetric NACA Airfoils 对称NACA翼型层流的数值解

Journal of fluid flow, heat and mass transfer Pub Date : 2020-10-01 DOI: 10.11159/enfht20.200

Prasanna M.S.S, Shashank Sadineni, Rahul Kotikalapudi, Prasad Pokkunuri

引用次数: 0

A Comparative Study of Diffusion Coefficients from Convective and IR Drying of Woodchip 木屑对流干燥与红外干燥扩散系数的比较研究

Journal of fluid flow, heat and mass transfer Pub Date : 2020-01-01 DOI: 10.11159/jffhmt.2020.007

M. Pryce, D. Cheneler, A. Martín, F. Aiouache

{"title":"A Comparative Study of Diffusion Coefficients from Convective and IR Drying of Woodchip","authors":"M. Pryce, D. Cheneler, A. Martín, F. Aiouache","doi":"10.11159/jffhmt.2020.007","DOIUrl":"https://doi.org/10.11159/jffhmt.2020.007","url":null,"abstract":"Convective and infared (IR) Halogen Drying processes are used in the woodchip biomass industry to test the moisture content of woodchip. Woodchip drying, though energy intensive, is necessary to increase the calorific content of woodchip, in turn increasing combustibility. The bulk process within the production of woodchip uses convective drying with agitation. Analysis of the diffusion in wood can be used to estimate the time to dry lumber to a specified moisture content value. Relationships between the effect of temperature and moisture content allow more accurate predictions and operational evaluations of driers. The aim of this study was to investigate constant heat source convective and IR drying by comparing the drying curves when batch drying a sample of woodchip biomass whilst controlling the heat source temperature at 328K, 338K, 348K and 358K. This was achieved through comparison of preexponential diffusion coefficients and activation energy, determining the temperature dependency of these terms in convective and IR drying of wetted wood. Lower temperatures increased drying time for both convective and IR drying, with convective drying taking up to 5 times longer than IR. The preexponential diffusion coefficient and activation energy found for IR drying were 3.555 ×10±0.824 ×10 m2.s-1 and 3.405 ×10±0.065 ×10 J.mol-1. The convective drying preexponential diffusion coefficient and activation energy calculated was 2.948 ×10±0.376 ×10 m2.s-1 and 1.619 ×10±0.037 ×10 J.mol-1 respectively.","PeriodicalId":92806,"journal":{"name":"Journal of fluid flow, heat and mass transfer","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83848387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Separation of Butanol Using Pervaporation: A Review of Mass Transfer Models 渗透蒸发分离丁醇:传质模型综述

Journal of fluid flow, heat and mass transfer Pub Date : 2019-02-11 DOI: 10.11159/JFFHMT.2019.002

H. Azimi, J. Thibault, F. Tezel

引用次数: 12

Numerical Study of Patient Respiration Effect on Bacterial Dispersion in a Surgery Room 手术室病人呼吸对细菌分散影响的数值研究

Journal of fluid flow, heat and mass transfer Pub Date : 2019-01-01 DOI: 10.11159/jffhmt.2019.004

A. Khademi, M. Saidi, M. Darbandi, G. Schneider

{"title":"Numerical Study of Patient Respiration Effect on Bacterial Dispersion in a Surgery Room","authors":"A. Khademi, M. Saidi, M. Darbandi, G. Schneider","doi":"10.11159/jffhmt.2019.004","DOIUrl":"https://doi.org/10.11159/jffhmt.2019.004","url":null,"abstract":"This study aims to present a numerical investigation of respiration influence on the particle concentration in a surgery room. Controlling the temperature and contamination in the surgery room is essential for safe and risk-free surgical procedures. Generally, in many hospital cleanrooms, utilized for operations such as open-heart surgery, organ transplantation, and neurosurgery, the reduction of pollutant particles is vital as a factor that can lead to capillary clogging during an operation. Also, reducing the concentration of large particles is very important, because dust particles may contain various pathogenic bacteria and viruses. Therefore, particle distribution and temperature control were numerically investigated in this study. At first, the particle concentration at specific zones was investigated to obtain the stability of the respiratory cycle. Then, the concentration and aggregation of particles around the patient’s head were measured on different pages along the coordinate axes while patient’s breathing was quite stable. Furthermore, the effect of the air conditioning system of the room on temperature distribution control by was studied in a specific area. The simulation results showed a considerable decrease in the particle concentration, but the particles were not eliminated from the room completely. Moreover, the higher temperature of the area around the patient's head caused by his breathing had little effect on room temperature, and the inlet air controlled the room temperature properly.","PeriodicalId":92806,"journal":{"name":"Journal of fluid flow, heat and mass transfer","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81565787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

CFD Modeling Of Turbulence in Channels Of Plate Heat Exchangers 板式换热器流道湍流的CFD模拟

Journal of fluid flow, heat and mass transfer Pub Date : 2018-06-01 DOI: 10.11159/ffhmt18.103

D. Mandić

{"title":"CFD Modeling Of Turbulence in Channels Of Plate Heat Exchangers","authors":"D. Mandić","doi":"10.11159/ffhmt18.103","DOIUrl":"https://doi.org/10.11159/ffhmt18.103","url":null,"abstract":"The subject of this paper is turbulence modeling of fluid flow in channels of plate heat exchangers for heating domestic hot water in heating substation in Belgrade. For testing of turbulence phenomena in the channels, this paper uses the standard K-ε model of turbulence. It is of particular importance that in this paper the modeling is made for different flow rates of fluids through channels, adopted in boundary conditions. The rate of flow in the input area of the channels was taken as the assumed average values of 0.01m / sec, and 0.1m / sec, which presupposed minimum and maximum values based on the measured values of these fluid velocities in the heat substations. On the basis of these assumed speeds, the values of the exchanged kinetic energy and the character of the change in the intensity of the projections of these velocities in the direction of all three axes are obtained. On the basis of these projections, we can determine the unsteadiness of the velocity and the return currents along these channels and in their contour surfaces as well as the \"dead spots\" in which there is no movement of the fluid. This work presents the calculated values of the Reynolds number of the streamline for the assumption velocity of fluid in channels. These phenomena can cause different problems in the transmission of heat and dirt in the channels of the plate heat exchangers where there is no circulation. Therefore, the obtained results can serve as a basis for dimensioning and selection of heat exchangers as well as for determining their optimal working conditions.","PeriodicalId":92806,"journal":{"name":"Journal of fluid flow, heat and mass transfer","volume":"86 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80750906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Using CFD in the Design Process of a Toilet Bowl CFD在马桶设计过程中的应用

Journal of fluid flow, heat and mass transfer Pub Date : 2018-06-01 DOI: 10.11159/JFFHMT.2019.001

A. Lopes, V. Costa

引用次数: 2

Selective Laser Melting of Metal Powders in Additive Manufacturing 增材制造中金属粉末的选择性激光熔化

Journal of fluid flow, heat and mass transfer Pub Date : 2017-06-01 DOI: 10.11159/icmie17.103

Tsung-Wen Tsai, Wei-Chin Huang, C. Chuang, D. Lin, Sung-Ho Liu, J. Horng, J. Chen

引用次数: 0

Improvements to Wire Bundle Thermal Modeling for Ampacity Determination. 电容重测定中线束热模型的改进。

Journal of fluid flow, heat and mass transfer Pub Date : 2017-01-01 DOI: 10.11159/jffhmt.2017.006

Steven L Rickman, Christopher J Iannello, Khadijah Shariff

{"title":"Improvements to Wire Bundle Thermal Modeling for Ampacity Determination.","authors":"Steven L Rickman, Christopher J Iannello, Khadijah Shariff","doi":"10.11159/jffhmt.2017.006","DOIUrl":"10.11159/jffhmt.2017.006","url":null,"abstract":"<p><p>Determining current carrying capacity (ampacity) of wire bundles in aerospace vehicles is critical not only to safety but also to efficient design. Published standards provide guidance on determining wire bundle ampacity but offer little flexibility for configurations where wire bundles of mixed gauges and currents are employed with various external insulation jacket surface properties. Thermal modeling has been employed in an attempt to develop techniques to assist in ampacity determination for these complex configurations. An earlier tool allowed analysis of wire bundle configurations but was constrained to configurations comprised of less than 50 elements. Additionally, for vacuum analyses, configurations with very low emittance external jackets suffered from numerical instability in the solution. A new thermal modeler is presented allowing for larger configurations and is not constrained by low bundle jacket surface infrared emittance calculations. Formulation of key internal radiation and interface conductance parameters is discussed including the effects of temperature and ambient air pressure on wire-to-wire thermal conductance. Test cases comparing model-predicted ampacity and that calculated from standards documents are presented.</p>","PeriodicalId":92806,"journal":{"name":"Journal of fluid flow, heat and mass transfer","volume":"27 1","pages":"47-53"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6800675/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90670484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0