Ruiqiong Wang¹, Tiantian Du², Jinchen Cao^2,*, Guoqiang Wang³

Frontiers in Heat and Mass Transfer, Vol.22, No.1, pp. 129-139, 2024, DOI:10.32604/fhmt.2024.047825

Abstract With the advancement of oilfield extraction technology, since oil-water emulsions in waxy crude oil are prone to be deposited on the pipe wall, increasing the difficulty of crude oil extraction. In this paper, the mesoscopic dissipative particle dynamics method is used to study the mechanism of the crystallization and deposition adsorbed on the wall. The results show that in the absence of water molecules, the paraffin molecules near the substrate are deposited on the metallic surface with a horizontal morphology, while the paraffin molecules close to the fluid side are arranged in a vertical column morphology. In the emulsified system,… More >

Mustafa Abdullah^*

Frontiers in Heat and Mass Transfer, Vol.22, No.1, pp. 141-156, 2024, DOI:10.32604/fhmt.2024.046788

Abstract This study investigates the influence of periodic heat flux and viscous dissipation on magnetohydrodynamic (MHD) flow through a vertical channel with heat generation. A theoretical approach is employed. The channel is exposed to a perpendicular magnetic field, while one side experiences a periodic heat flow, and the other side undergoes a periodic temperature variation. Numerical solutions for the governing partial differential equations are obtained using a finite difference approach, complemented by an eigenfunction expansion method for analytical solutions. Visualizations and discussions illustrate how different variables affect the flow velocity and temperature fields. This offers comprehensive insights into MHD flow behavior… More >

Perez Joan¹, Fusco Giovanni¹, Sadahiro Yukio²

Revue Internationale de Géomatique, Vol.31, No.2, pp. 303-327, 2022, DOI:10.3166/RIG.31.303-327© 2022

Abstract This paper presents different methods implemented with the aim of studying urban dynamics at the building level. Building types are identified within a comprehensive vector-based building inventory, spanning over at least two time points. First, basic morphometric indicators are computed for each building: area, floor-area, number of neighbors, elongation, and convexity. Based on the availability of expert knowledge, different types of classification and clustering are performed: supervised tree-like classificatory model, expert-constrained k-means and combined SOM-HCA. A grid is superimposed on the test region of Osaka (Japan) and the number of building types per cell and for each period is computed,… More >

Morteza Eslamian^*

Frontiers in Heat and Mass Transfer, Vol.2, No.4, pp. 1-20, 2011, DOI:10.5098/hmt.v2.4.3001

Abstract Recent advances in thermodiffusion (Soret effect) in binary and higher multicomponent liquid mixtures are reviewed. The mixtures studied include the hydrocarbon, associating, molten metal and semiconductor, polymer, and DNA mixtures. The emphasis is placed on the theoretical works, particularly models based on the nonequilibrium thermodynamics, although other approaches such as the statistical, kinetic and hydrodynamic approaches are discussed as well. For each mixture, the major theoretical and experimental works are discussed and the research trends and challenges are addressed. Some of the challenges include a need for combining various methods to develop a comprehensive theoretical model or at least to… More >

Nessa Johnson, John Abraham^*, Zach Helgeson, Michael Hennessey

Frontiers in Heat and Mass Transfer, Vol.2, No.2, pp. 1-7, 2011, DOI:10.5098/hmt.v2.2.3006

Abstract A numerical simulation has been performed on the hemodynamics associated with embolization procedures. The flow geometry includes a multibranch artery which is upstream of a targeted tumor. During the procedure, drug-eluting particles are released into the local arterial geometry and are carried downstream by the flowing blood. The intention is to cause embolization of a daughter artery which feeds the tumor. As particles are injected into the blood stream, and as the embolization progresses, it is possible for the particulates to substantially alter the blood flow in the main artery. This alteration may lead to a maldistribution of blood flow… More >

Tomio Okawa^*,†

Frontiers in Heat and Mass Transfer, Vol.3, No.1, pp. 1-8, 2012, DOI:10.5098/hmt.v3.1.3001

Abstract The present article summarizes the studies on the thermalhydraulic condition under which the onset of nucleate boiling (ONB) is triggered in subcooled flow boiling. Available correlations and experimental data show that the ONB is tended to be delayed in mini and microchannels. It is known that the ONB condition is significantly dependent on the surface condition even in conventional-sized channels. Accumulation of ONB data accompanied by the information on the surface condition is therefore considered of importance to elucidate the mechanisms of boiling incipience in microchannels. Discussion is also made for the bubble dynamics observed in mini and microchannels. It… More >

Pranab Kumar Mondal^*, Sanchayan Mukherjee

Frontiers in Heat and Mass Transfer, Vol.3, No.3, pp. 1-6, 2012, DOI:10.5098/hmt.v3.3.3004

Abstract The present paper deals with the analytical investigation for the limiting value of Nusselt number, including the effect of viscous dissipation on heat transfer for a laminar shear driven flow between two infinite parallel plates, where the bottom plate is fixed and the top plate is moving in an axial direction at a constant speed. The study concentrates on hydro-dynamically fully developed flow of a Newtonian fluid of constant properties without considering the axial conduction in the fluid. To investigate the effect of viscous dissipation on heat transfer by defining the limiting Nusselt number, plates are kept at constant equal… More >

Alexandre Vaudrey^a,*, Philippe Baucour^b, François Lanzetta^b, Raynal Glises^b

Frontiers in Heat and Mass Transfer, Vol.3, No.3, pp. 1-8, 2012, DOI:10.5098/hmt.v3.3.3001

Abstract Producing electrical work in consuming chemical energy, the fuel cell (FC) is forced by the 2^nd law to reject heat to its surrounding. However, as it occurs for any other type of engine, this thermal energy cannot be exchanged in an isothermal way in finite time or through finite areas. As it was already done for various types of systems, including chemical engines, the fuel cell is here studied within the finite time thermodynamics framework. An endoreversible fuel cell is then defined, internally reversible but producing entropy during heat exchanges with its ambiance. Considering usual H₂/O₂ and H₂/air chemical reactions… More >

Muhammad Shoaib Arif^1,2,*, Kamaleldin Abodayeh¹, Yasir Nawaz²

CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.3, pp. 3417-3434, 2024, DOI:10.32604/cmes.2024.046944

Abstract This study focuses on the urgent requirement for improved accuracy in disease modeling by introducing a new computational framework called the Hybrid SIR-Fuzzy Model. By integrating the traditional Susceptible-Infectious-Recovered (SIR) model with fuzzy logic, our method effectively addresses the complex nature of epidemic dynamics by accurately accounting for uncertainties and imprecisions in both data and model parameters. The main aim of this research is to provide a model for disease transmission using fuzzy theory, which can successfully address uncertainty in mathematical modeling. Our main emphasis is on the imprecise transmission rate parameter, utilizing a three-part description of its membership level.… More >

Xinyu Zhang¹, Wenjie Xia², Yang Wang^3,4, Liang Wang^1,*, Xiaofeng Liu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.3, pp. 3047-3061, 2024, DOI:10.32604/cmes.2023.046922

Abstract Graphene aerogel (GA), as a novel solid material, has shown great potential in engineering applications due to its unique mechanical properties. In this study, the mechanical performance of GA under high-velocity projectile impacts is thoroughly investigated using full-atomic molecular dynamics (MD) simulations. The study results show that the porous structure and density are key factors determining the mechanical response of GA under impact loading. Specifically, the impact-induced penetration of the projectile leads to the collapse of the pore structure, causing stretching and subsequent rupture of covalent bonds in graphene sheets. Moreover, the effects of temperature on the mechanical performance of… More >