Kentaro Doi^1,2, Ikumi Onishi¹, Satoyuki Kawano^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.77, No.2, pp. 113-136, 2011, DOI:10.3970/cmes.2011.077.113

Abstract Hydrogen technologies are currently one of the most actively researched topics. A lot of researches have tied to enhance their energy conversion efficiencies. In the present study, numerical analyses have been carried out focusing on hydrogen-storage carbon materials which are expected to realize high gravimetric and volumetric capacities. In particular, dissociative adsorption processes of H₂ molecules above graphene surfaces have been investigated by ab initio molecular dynamics. The present results indicate that a steric graphene surface plays an important role in enhancing the charge transfer which induces dissociation of H₂ and adsorption of H atoms on the surface. The dissociation… More >

Chein-Shan Liu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.12, No.3, pp. 161-180, 2006, DOI:10.3970/cmes.2006.012.161

Abstract Materials' internal spacetime may bear certain similarities with the external spacetime of special relativity theory. Previously, it is shown that material hardening and anisotropy may cause the internal spacetime curved. In this paper we announce the third mechanism of mixed-control to cause the curvedness of internal spacetime. To tackle the mixed-control problem for a Prager kinematic hardening material, we demonstrate two new formulations. By using two-integrating factors idea we can derive two Lie type systems in the product space of M^m+1⊗Mⁿ⁺¹. The Lie algebra is a direct sum of so(m,1)⊕so(n,1), and correspondingly the symmetry group is a direct product of… More >

Sanjay Mittal¹

CMES-Computer Modeling in Engineering & Sciences, Vol.27, No.1&2, pp. 63-78, 2008, DOI:10.3970/cmes.2008.027.063

Abstract Flow past a circular cylinder looses stability at a Reynolds number,Re~47. It has been shown, in the past, that the linear stability analysis (LSA) of the steady state solution can predict not only the critical Re, but also the non-dimensional frequency, St, of the associated instability. For larger Re the non-linear effects become important and the LSA of the steady-state flow does not predict the correct St. It is shown that, in general, the LSA applied to the time-averaged flow can result in useful information regarding its stability. This idea is applied to the Re = 100 flow past a… More >

Toufik Arrif^1,2, Abdelmadjid Chehhat^3,4,*, Essam Abo-Serie⁵, Adel Benchabane²

FDMP-Fluid Dynamics & Materials Processing, Vol.14, No.4, pp. 223-242, 2018, DOI:10.32604/fdmp.2018.01799

Abstract This work presents a numerical investigation on heat transfer and fluid-dynamic aspects for a solar open cavities in an extended fluid flow domain. The vertical wall inside the open cavities facing the aperture is assumed to be isothermal while the other walls are kept insulated. Heat transfer steady laminar natural convection is studied by solving the non-dimensional governing equations of mass, momentum and energy in the framework of a finite volume method. The analysis are carried out under Rayleigh number range of 9.41×10⁵ to 3.76×10⁶, inclination 0° to 90° and opening ratio 0.25, 0.5 and 1. The model results for… More >

Kamil Sobczak^1,2

FDMP-Fluid Dynamics & Materials Processing, Vol.13, No.1, pp. 49-57, 2017, DOI:10.3970/fdmp.2017.013.049

Abstract The paper presents a simple although effective method of obtaining gold and silver nanoparticles of average size of less than 3 nm. The nanoparticles were obtained by the Bredig’s electric arc method. Then colloidal preparations were centrifuged with acceleration equals to 29000 xg. It has been showed that subjecting the colloid to the hour centrifugation process repeated four times allows to obtain nanoparticles whose size does not exceed 5 nm. The nanoparticles prepared using this method were characterized by a high purity that depended only on the water and the cleanliness of the noble metal wire which have been used.… More >

Mustapha FARAJI¹

FDMP-Fluid Dynamics & Materials Processing, Vol.13, No.1, pp. 19-36, 2017, DOI:10.3970/fdmp.2017.013.019

Abstract A two-dimensional numerical model that accounts for heat transfer by conduction and natural convection in the molten region of nano enhanced Phase Change Material (PCM) is performed. Numerical investigations were conducted using an enthalpy- porosity method in order to examine the impact of the dispersion of copper (CuO) nanoparticles on the heat source temperature and the effect on the heat sink secured working time and the melting rate. Results show that heat spreads more easily along the conducting plate and to the PCM and, consequently, the PCM melts rapidly and the heat source is efficiency cooled by the addition of… More >

Mustapha Faraji¹, El Alami Mustapha, Najam Mostafa

FDMP-Fluid Dynamics & Materials Processing, Vol.10, No.2, pp. 279-298, 2014, DOI:10.3970/fdmp.2014.010.279

Abstract A study is reported of heat transfer and melting in a fan-less thermal management system consisting of an insulated horizontal cavity filled with a phase change material (PCM) and heated from below by a conducting plate supporting three identical protruding heat sources. Such a PCM enclosure can be used as a heat sink for the cooling of electronic components. The advantage of this cooling strategy is that PCMs characterized by high energy storage density and small transition temperature interval, are able to store a high amount of heat (thereby providing efficient passive cooling). A two-dimensional simulation model is developed that… More >

K. Lahmer¹, R. Bessaïh¹, A. Scipioni², M. El Ganaoui²

FDMP-Fluid Dynamics & Materials Processing, Vol.10, No.1, pp. 149-162, 2014, DOI:10.3970/fdmp.2014.010.149

Abstract This paper summarizes the outcomes of a numerical study about the phenomenon of hydrogen absorption in an axisymmetric tank geometry containing magnesium hydride heated to 300˚C and at moderate storage pressure 1 MPa. The governing equations are solved with a fully implicit finite volume numerical scheme (as implemented in the commercial software FLUENT). Different kinetic reaction equations modeling hydrogen absorption are considered and the related numerical simulations are compared with experimental results. Spatial and temporal profiles of temperature and concentration in hydride bed are plotted. More >

Mohamed Rady¹, Eric Arquis²

FDMP-Fluid Dynamics & Materials Processing, Vol.6, No.2, pp. 137-152, 2010, DOI:10.3970/fdmp.2010.006.137

Abstract In the present article, differential scanning calorimetry (DSC) and a modified T-history method have been used to study the phase changing behavior of granular composites. Further modifications and improvements of the two methods are employed to handle granular materials undergoing phase change over a temperature range. A simple procedure has been advised to obtain accurate results from the DSC measurements based on the estimation of the thermal resistance between the sample and its enclosure. The concept of enthalpy and its relationship with temperature has been employed in the T-history analysis to obtain enthalpy-temperature and apparent heat capacity curves similar to… More >

A.A. Ivanova¹, V.G. Kozlov^1,2,3, D.A. Polezhaev¹, D. Pareau³, M. Stambouli³

FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.3, pp. 211-220, 2008, DOI:10.3970/fdmp.2008.004.211

Abstract The problem for the optimization of mass-transfer on the interface of two immiscible liquids by means of vibrational hydromechanics is studied experimentally. A new vibrational cell of Lewis's type expressly conceived for such purposes is described. Flow is generated by activators in the form of disks inducing translational axial oscillations near the opposite end faces of the cavity. It is shown that such vibrating disks can lead to the onset of a large-scale toroidal whirlwind effectively mixing the liquid throughout the volume. According to the experiments, in particular, axisymmetrical radial flows are generated on both sides of the horizontal liquid… More >