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11.
Mahmoud Jourabian Mousa Farhadi Ahmad Ali Rabienataj Darzi 《Theoretical and Computational Fluid Dynamics》2016,30(6):579-603
In this study, the melting process of ice as a phase-change material (PCM) saturated with a nickel–steel porous matrix inside a horizontal elliptical tube is investigated. Due to the low thermal conductivity of the PCM, it is motivated to augment the heat transfer performance of the system simultaneously by finding an optimum value of the aspect ratio and impregnating a metallic porous matrix into the base PCM. The lattice Boltzmann method with a double distribution function formulated based on the enthalpy method, is applied at the representative elementary volume scale under the local thermal equilibrium assumption between the PCM and porous matrix in the composite. While reducing or increasing the aspect ratio of the circular tubes leads to the expedited melting, the 90\(^{\circ }\) inclination of each elliptical tube in the case of the pure PCM melting does not affect the melting rate. With the reduction in the porosity, the effective thermal conductivity and melting rate in all tubes promoted. Although the natural convection is fully suppressed due to the significant flow blockage in the porous structure, the melting rates are generally increased in all cases. 相似文献
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Mahmoud Jourabian Ahmad Ali Rabienataj Darzi 《International Journal of Computational Fluid Dynamics》2013,27(9-10):451-462
An enthalpy-based Lattice Boltzmann method (LBM) with double-distribution function (DDF) model is used to investigate numerically the effects of inserting a porous matrix on the heat transfer performance of the phase change material (PCM). Simulations are carried out for melting of ice in saturated Al2O3 porous matrix encapsulated in a concentric annulus. The process is considered as a conduction/convection controlled phase change problem at a representative elementary volume (REV) scale. The present results are validated by previous published numerical simulations of melting with and without porous media. In this research paper, the effects of decreasing the porosity on the temperature contours, flow patterns within the melt zone, complete melting time of the PCM and average Nusselt number are discussed qualitatively and quantitatively. 相似文献
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Several nickel phosphate molecular sieves were synthesized by conventional heating (CH) and microwave assisted hydrothermal (MAH). Nickel phosphate VSB‐5 (Versailles Santa Barbara‐5) was synthesized with conventional oven for 72 h or with microwave for 1 h and followed by conventional oven for 48 h in the presence of (2‐hydroxyethyl) trimethylammonium hydroxide as template. The phase transformation is observed by variation of CH time for the synthesis of nickel phosphate molecular sieves. At CH time of 24 h, the VSB‐5 crystal together α‐Ni2P2O7, Ni2P4O12 and unknown phases were produced but the pure VSB‐5 crystal was obtained in the CH time of 48 h or more. At high content of nickel, a mixture of α‐Ni2P2O7, Ni2P4O12 phases and small amount of VSB‐5 crystal, was achieved but pure VSB‐5 crystal was obtained in the lower level of nickel and other phases are vanished. An efficient ultrasonic‐assisted aging was found for the synthesis of nickel phosphate molecular sieve, in which by ultrasonic mixing of 0.5 h followed microwave of 1 h, the CH time is significantly reduced from 48 to 24 h. The morphology of nickel phosphate crystals is highly influenced in the presence of ethylene glycol as co‐solvent. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Safaralizadeh Elnaz Darzi Simin Janitabar Mahjoub Ali Reza Abazari Reza 《Research on Chemical Intermediates》2017,43(2):1197-1209
Research on Chemical Intermediates - Using a simple impregnation process, the present study has introduced a novel route for the photosensitization of TiO2 nanoparticles using Sudan black B dye as... 相似文献
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In this paper, the authors have established the \(\left( G^{\prime }/G\right)\)-expansion method to find exact solutions for conformable time fractional generalized seventh-order KdV equation (FGKdV7). This method is an effective method in finding exact traveling wave solutions of nonlinear evolution equations in mathematical physics. The effectiveness of this manageable method has been shown by applying it to several particular cases of the FGKdV7. The present approach has the potential to be applied to other nonlinear fractional differential equations. All of the numerical calculations in the present study have been performed on a PC applying some programs written in Mathematica. 相似文献
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Mahmoud Jourabian Mousa Farhadi Ahmad Ali Rabienataj Darzi 《Heat and Mass Transfer》2013,49(4):555-565
Heat transfer and fluid flow processes of natural convection melting of a phase change material are simulated numerically inside a partially heated square cavity. The momentum and energy equations are solved by using enthalpy-based lattice Boltzmann method combined with multi distribution function model. In this communication, the dependence of liquid fraction, temperatures of vertical nodes and average Nusselt number on the positions of heated plates is investigated quantitatively. 相似文献
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Ali Morsali Ali R. Mahjoub Simin Janitabar Darzi Mohammad J. Soltanian 《无机化学与普通化学杂志》2003,629(14):2596-2599
The 1:2 adduct lead(II) complexes with 1, 10‐phenanthroline (phen) containing three different anions, [Pb(phen)2(CH3COO)X] (X=NCS—, NO3— and ClO4—), have been synthesized and characterized by CHN elemental analysis, IR‐, 1H‐ and 13C NMR spectroscopy. The structure of [Pb(phen)2(CH3COO)(ClO4)] was determined by single crystal X‐ray analysis. The Pb atom of the monomeric complex is coordinated by four nitrogen atoms of two 1, 10‐phenanthroline ligands and two oxygen atoms of the acetate ligand to form an irregular octahedron. The arrangement of the 1, 10‐phenanthroline and acetate ligands, exhibits a coordination gap around the PbII ion, possibly occupied by a stereochemical electron active lone pair on lead(II), which results in a hemidirected lead compound. The π‐π stacking interaction between the parallel aromatic rings may help to increase the coordination ‘gap’ around the PbII ion. 相似文献
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In this paper, the existence and uniqueness of initial value problems for nonlinear Langevin equation involving three fractional orders are discussed. We use a new norm that is convenient for the fractional and singular differential equations. This norm and the contraction mapping principles are the main tools for investigating the existence and uniqueness of the desired issue. The fractional derivatives are described in Caputo sense.
相似文献19.
Mahmoud Jourabian Mousa Farhadi Kurosh Sedighi AhmadAli Rabienataj Darzi Yousef Vazifeshenas 《国际流体数值方法杂志》2012,70(3):313-325
In this study, a numerical investigation of melting phenomenon with natural convection in a cavity with fin has been performed using enthalpy‐based lattice Boltzmann method. The lattice D2Q9 model was applied to determine the density and velocity fields, and the D2Q5 model for the temperature field. The effect of vertical position and length of the fin on the melting rate was studied. The simulations were carried out for Stefan number of 10, Rayleigh number of 10 5 and relative thermal conductivity (kfin∕kfluid) ranging from 5 to 30. The obtained results show that the rate of melting increases when the relative thermal conductivity and the length of the fin become greater. We also found that the variation of vertical position of the fin from bottom to middle has an insignificant effect on melting while it causes the increase of full melting time when the fin is mounted on the top of the cavity. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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