Frontiers in Heat and Mass Transfer, Vol.3, No.1, pp. 1-3, 2012, DOI:10.5098/hmt.v3.1.1001

Abstract This article has no abstract. More >

Zongjun Yin^*, Rong Su, Hui Xu

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.3, pp. 487-504, 2024, DOI:10.32604/fdmp.2023.042631

Abstract In this study, numerical simulations of the pinching-off phenomena displayed by the dispersed phase in a continuous phase have been conducted using COMSOL Multiphysics (level-set method). Four flow patterns, namely “drop flow”, “jet flow”, “squeeze flow”, and “co-flow”, have been obtained for different flow velocity ratios, channel diameter ratios, density ratios, viscosity ratios, and surface tension. The flow pattern map of two-phase flow in coaxial microchannels has been obtained accordingly, and the associated droplet generation process has been critically discussed considering the related frequency, diameter, and pinch-off length. In particular, it is shown that the larger the flow velocity ratio,… More > Graphic Abstract

Muataz S. Alhassan¹, Ameer A. Alameri², Andrés Alexis Ramírez-Coronel³, I. B. Sapaev^4,5,6, Azher M. Abed^7,*, David-Juan Ramos-Huallpartupa⁸, Rahman S. Zabibah⁹

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.2, pp. 311-323, 2024, DOI:10.32604/fdmp.2023.026782

Abstract In line with recent studies, where it has been shown that nanofluids containing graphene have a stronger capacity to boost the heat transfer coefficient with respect to ordinary nanofluids, experiments have been conducted using water with cobalt ferrite/graphene nanoparticles. In particular, a circular channel made of copper subjected to a constant heat flux has been considered. As nanoparticles are sensitive to the presence of a magnetic field, different conditions have been examined, allowing both the strength and the frequency of such a field to span relatively wide ranges and assuming different concentrations of nanoparticles. According to the findings, the addition… More >

Siham Hammid¹, Khatir Naima², Omolayo M. Ikumapayi³, Cheikh Kezrane¹, Abdelkrim Liazid⁴, Jihad Asad⁵, Mokdad Hayawi Rahman⁶, Farhan Lafta Rashid⁷, Naseer Ali Hussien⁸, Younes Menni^2,9,*

CMES-Computer Modeling in Engineering & Sciences, Vol.138, No.1, pp. 273-299, 2024, DOI:10.32604/cmes.2023.028951

Abstract The objective of this investigation is to assess the effect of obstacles on numerical heat transfer and fluid flow momentum in a rectangular microchannel (MC). Two distinct configurations were studied: one without obstacles and the other with alternating obstacles placed on the upper and lower walls. The research utilized the thermal lattice Boltzmann method (LBM), which solves the energy and momentum equations of fluids with the BGK approximation, implemented in a Python coding environment. Temperature jump and slip velocity conditions were utilized in the simulation for the MC and extended to all obstacle boundaries. The study aims to analyze the… More >

Zihuan Ma¹, Xiang Ma¹, Chengyu Hu¹, Jinjia Wei^1,2,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.26, No.2, pp. 1-1, 2023, DOI:10.32604/icces.2023.08963

Abstract Flow boiling in microchannel heat sinks is considered as a promising cooling solution for electronic components. Higher heat flux can be effectively dissipated by the utilization of the latent heat of vaporization. However, most of the current studies on flow boiling in microchannels are mainly experimental investigations and two-dimensional numerical studies. In this paper, the Volume of Fluid (VOF) model combined with the Lee evaporation-condensation phase change model is used to simulate the flow boiling of HFE7100 in horizontal microchannels by three-dimensional conjugate numerical simulation. The numerical simulation results are compared with the experimental results [1], showing an excellent agreement.… More >

Yun Whan Na^* , J. N. Chung^†

Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-14, 2018, DOI:10.5098/hmt.11.36

Abstract Flow instabilities of convective two-phase boiling in a trapezoidal microchannel were investigated. using a three-dimensional numerical model. Parameters such as wall temperature and inlet pressure that characterize the instability phenomena of flow boiling with periodic flow patterns were studied at different channel wall heat fluxes and flow mass fluxes. Results were obtained for various wall heat flux levels and mass flow rates. The numerical results showed that large amplitude and short period oscillations for wall temperature and inlet pressure fluctuations are major characteristics of flow instability. The wall temperature fluctuations are mainly initiated by the transition from bubbly to slug… More >

Rahouadja Zarita^*, Madjid Hachemi

Frontiers in Heat and Mass Transfer, Vol.12, pp. 1-12, 2019, DOI:10.5098/hmt.12.5

Abstract In this work, heat transfer enhancement in a microchannel using water-Ag nanofluid has been investigated numerically by the lattice Boltzmann method (LBM) by adopting the stream and collide algorithm, with the (BGK) approximation. The base fluid and the suspended nanoparticles are considered as a homogeneous mixture. And single phase model with first order slip and jump boundary conditions has been adopted. Thermophysical properties of water-Ag nanofluid are estimated by the theoretical models. Effects of change in nanoparticle volume fractions, Reynolds number and Knudsen number are considered. It was concluded that change in nanoparticle volume fractions did not have significant effects… More >

Zhipeng Tang^a, Yongbin Zhang^b,*

Frontiers in Heat and Mass Transfer, Vol.14, pp. 1-5, 2020, DOI:10.5098/hmt.14.26

Abstract The critical flow rate through a micro/nano slit pore for starting the adsorbed layer-fluid or adsorbed layer-wall interfacial slippage is calculated by a multiscale scheme. There are the physical adsorbed layers on the channel walls and the intermediate continuum fluid which are respectively in noncontinuum and continuum flows. The flow factor approach model for nanoscale flow is used to simulate the adsorbed layer flow, and a continuum model describes the continuum fluid flow. The boundary between the adsorbed layer and the continuum fluid or the boundary between the adsorbed layer and the channel wall are treated as the interfacial slippage.… More >

Ammar Hassan Soheel, Omar Mahmood Jumaah, Ahmed Mustaffa Saleem^*

Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-7, 2021, DOI:10.5098/hmt.17.21

Abstract This paper presents a simulation and investigation of the heat transfer coefficient, pressure drop, and thermal conductivity of two - phase flow. The simulation was performed of mixtures (Al₂O₃ nanoparticles with R134a refrigerant). The size of nanoparticles (Al₂O₃) which is used in this study is 30 nm and volume concentrations are 0.015 and 0.03. The two – phase flowing through a horizontal circular microchannel of (diameter 100 µm, and length 20 mm) under constant heat flux (3000 W/m²) and constant wall temperature (330 K), also in this study used the inlet temperature at -20 oC and mass flow rates are… More >

Vikas Gulia, Anirban Sur^*

Frontiers in Heat and Mass Transfer, Vol.18, pp. 1-10, 2022, DOI:10.5098/hmt.18.40

Abstract Over the past few decades, the world is moving towards miniature products owing to the technological developments in variegated industrial domains such as aerospace, biomedical, electronics, etc. This has led to the exponential growth of efficient micro cooling systems which are light in weight and have effective thermal performance. Microchannel Heat Sinks and Microchannel Heat Exchangers are the widely adopted solutions for such efficient micro cooling systems. This paper comprehensively reviews the recent developments in the field of Microchannel Heat Sinks and Microchannel Heat Exchangers. Initially, the concept of microchannel cooling is discussed. Further, a comprehensive review of materials, fabrication… More >