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… More >

Xiaokang Tian¹, Kai Yue^1,2,*, Yu You^1,2, Yongjian Niu¹, Xinxin Zhang^1,2

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.2, pp. 301-317, 2021, DOI:10.32604/fdmp.2021.013521

Abstract The heat transfer performances of a microchannel heat sink in the presence of a nanofluid can be affected by the attachment of nanoparticle (NP) on the microchannel wall. In this study, the mechanisms underlying NP transport and attachment are comprehensively analyzed by means of a coupled double-distribution-function lattice Boltzmann model combined with lattice-gas automata. Using this approach, the temperature distribution and the two-phase flow pattern are obtained for different values of the influential parameters. The results indicate that the number of attached NPs decrease exponentially as their diameter and the fluid velocity grow. An increase… 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 More >

A. Aissa^{1, *}, M. E. A. Slimani², F. Mebarek-Oudina³, R. Fares¹, A. Zaim¹, L. Kolsi^{4, 5}, M. Sahnoun¹, M. E. Ganaoui⁶

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.2, pp. 147-159, 2020, DOI:10.32604/fdmp.2020.04073

Abstract In this paper, flow of slightly rarefied compressible nitrogen in microchannels has been investigated numerically for low values of Reynolds and Mach numbers. The 2D governing equations were solved using Finite Element Method with first-order slip boundary conditions (Comsol Multiphysics software). A validation was performed by comparing with similar configuration from the literature. It was found that our model can accurately predict the pressure driven flow in microchannels. Several interesting findings are reported about the Relative pressure, longitudinal velocity, Mach number, effect of gas rarefaction and flow rate. 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 More >

Tawfiq Chekifi^1,*

FDMP-Fluid Dynamics & Materials Processing, Vol.15, No.5, pp. 545-555, 2019, DOI:10.32604/fdmp.2019.01793

Abstract Numerical simulation using Ansys Fluent code is performed, to investigate droplet generation in cross-junction based VOF method. Droplets of water are generated by the shear stress applied by continuous phase (oil), two configurations of cross-junction are suggested; the first is a simple model no modification is performed at the outer channel, while the second model is characterized by a lateral obstacle. we study the effect of velocity ratio, viscous parameter, interfacial tension, flow condition on droplet size and frequency, the effect of lateral obstacles on droplets generation is also focused and analysed. The numerical simulations… More >

Zhen Wang¹, Yi Sui¹, Wen Wang¹, Dominique Barthѐs-Biesel², Anne-Virginie Salsac^2,*

Molecular & Cellular Biomechanics, Vol.16, Suppl.2, pp. 42-43, 2019, DOI:10.32604/mcb.2019.07148

Abstract Capsules are liquid droplets enclosed by a thin membrane which can resist shear deformation. They are widely found in nature (e.g. red blood cells) and in numerous applications (e.g. food, cosmetic, biomedical and pharmaceutical industries [1]), where they often flow through a complicated network of tubes or channels: this is the case for RBCs in the human circulation or for artificial capsules flowing through microfluidic devices. Central to these flows is the dynamic motion of capsules at bifurcations, in particular the question of path selection. A good understanding of this problem is indeed needed to… More >

Xinyu You¹, Jionghui Liu¹, Nan Hua^1,3, Ji Wang⁵, Rongji Xu^1,4, Guangxu Yu², Huasheng Wang^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.3, pp. 143-143, 2019, DOI:10.32604/icces.2019.04732

Abstract The paper reports preliminary measurement results for flow boiling heat transfer of refrigerant R1233zd in parallel horizontal microchannels. The aluminum test section consists of two blocks and has 10 parallel channels with 1.0 mm in width, 1.5 mm in height and 440 mm in length. Five small thermocouple holes with diameter 0.6 mm and depth 20 mm were drilled at 10 locations along the channel on the two aluminum blocks, respectively. Local heat flux and channel surface temperature along the channel were obtained using the inverse heat conduction method [1] based on temperatures accurately measured 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 More >

C.T. Lee¹, C.C. Lee²

CMES-Computer Modeling in Engineering & Sciences, Vol.104, No.5, pp. 375-403, 2015, DOI:10.3970/cmes.2015.104.375

Abstract In this article, we demonstrate a numerical 3-D chip, and studied the capillary dynamics inside the microchannel. We applied the level set method on the Navier-Stokes equation which incorporates the surface tension and two-phase flow characteristics. We analyzed the capillary dynamics near the junction of two microchannels. Such a highlighting point is important that it not only can provide the information of interface behavior when fluids are made into a head-on collision, but also emphasize the idea for the design of the chip. In addition, we study the pressure distribution of the fluids at the More >