Numerical simulation of heat transfer enhancement for natural convection in a cubical enclosure filled with Al2O3/water and Ag/water nanofluids

In the present study, the natural convective heat transfer in a cube filled with Al₂O₃/H₂O and Ag/H₂O nanofluids is investigated numerically. Commercial CFD code FLUENT has been used to simulate water-based nanofluid considering it as a single-phase fluid. The influence of different parameters, such as the Rayleigh number and the nanoparticle volume fraction, is studied. The velocity vectors and the isotherm profiles are plotted. The variation of the Average Nusselt number at the hot wall and the variation of y-component of velocity are presented and discussed. The numerical results show a decrease in the heat transfer with the increase in the particle volume fraction and the same trend in the increase of the Nusselt number with the Rayleigh number.     

Numerical investigation of mixed convection heat transfer behavior of nanofluid in a cavity with different heat transfer areas

Journal of Thermal Analysis and Calorimetry - The main purpose of this research is the numerical modeling of laminar mixed convection heat transfer inside an open square cavity with different heat...     

Numerical study of mixed convection heat transfer inside a vertical microchannel with two-phase approach

Journal of Thermal Analysis and Calorimetry - The current study investigates the laminar and two-phase nanofluid flow inside a two-dimensional rectangular microchannel with the ratio of length to...     

Taguchi optimization for natural convection heat transfer of Al2O3 nanofluid in a partially heated cavity using LBM

Journal of Thermal Analysis and Calorimetry - In the present study for the first time, Taguchi approach was applied to specify the optimal condition of the parameters in the natural convection heat...     

Numerical investigation of mixed convection heat transfer of a nanofluid in a circular enclosure with a rotating inner cylinder

Journal of Thermal Analysis and Calorimetry - In the present paper, mixed convection heat transfer of water–Al2O3 nanofluid in the space between two cylinders is investigated numerically. The...     

Hybrid conduction,convection and radiation heat transfer simulation in a channel with rectangular cylinder

Journal of Thermal Analysis and Calorimetry - The innovation of this study is to investigate the combination effect of thermal radiation and convection in the hybrid heat transfer between solid and...     

An exact analysis of low Peclet number heat transfer in laminar flow with axial conduction

An exact method of analysis is presented for solving the low Peclet number thermal entry region problem for laminar flow inside a circular tube, including the effects of axial conduction in both the upstream and the downstream directions. The local Nusselt number for uniform wall heat flux conditions is determined for Pe = 0.5, 1, 5, 20, 45 and ∞ at different locations along the thermal entry region. The method is simple and easy to apply, and provides a new approach for the analysis of thermal entry region problems with axial conduction.     

Effect of Al2O3/water nanofluid on performance of parallel flow heat exchangers

Journal of Thermal Analysis and Calorimetry - A comprehensive experimental investigation is intended to survey consequence of nanofluid on performance of sundry parallel flow heat exchangers with...     

Numerical investigation of laminar flow and heat transfer in a channel using combined nanofluids and novel longitudinal vortex generators

Journal of Thermal Analysis and Calorimetry - Enhancement of heat transfer in plate-fin heat exchangers can be obtained using vortex generators (VG). The three-dimensional laminar flow of...     

Impacts of moving wall and heat-generating element on heat transfer and entropy generation of Al2O3/H2O nanofluid

Development of various electronic devices demands to create effective cooling complexes. The present paper deals with computational analysis of mixed convection cooling of heat-conducting and heat-generating element located inside an alumina–water nanofluid enclosure with upper moving wall. Usage of upper moving wall, nanofluid and cooling vertical walls allows to create the effective cooling process. Analysis has been performed numerically using the Oberbeck–Boussinesq equations. The effects of nanoparticles concentration, heat source location and upper wall velocity on flow structures, heat exchange and entropy generation have been investigated. It has been ascertained that effective cooling of the heated element occurs for high Reynolds number and central position of the heat-generating element.

     

Numerical study on heat loss from the surface of solar collector tube filled by oil-NE-PCM/Al2O3 in the presence of the magnetic field

Journal of Thermal Analysis and Calorimetry - The natural convection of the oil-NE-PCM/Al2O3 inside the parabolic trough collector is studied. To simulate nanoencapsulate-phase change material...     

Scaling group analysis of bioconvective micropolar fluid flow and heat transfer in a porous medium

Journal of Thermal Analysis and Calorimetry - The current and potential applications of bioconvection renewed drive for theoretical research on synthesis and process control in biofuel cells and...     

微波诱导Fe2O3/Al2O3催化剂催化氧化处理水中苯酚

 以γ-Al2O3为载体,采用浸渍-焙烧法制备了Fe2O3/Al2O3催化剂,并将其应用于微波诱导催化氧化处理模拟含酚废水. X射线衍射和X射线荧光光谱测试结果表明,活性组分氧化铁在催化剂中以α-Fe2O3的形式存在,其含量为3.71%. 与载体氧化铝相比,Fe2O3/Al2O3催化剂的比表面积和平均孔径及平均孔容略有降低. 对于100 mg/L的模拟含酚废水,最佳的处理工艺条件为: 微波辐照功率400 W,辐照时间5 min,催化剂加入量60 g/L,H2O2浓度600 mg/L,体系pH＞4. 在此工艺条件下,水中苯酚的去除率达97.98%. 催化剂连续使用20次后苯酚去除率仍达96.34%. 表观反应动力学研究表明,在氧化铁催化剂存在的条件下,微波诱导H2O2产生氧化性极强的羟基自由基,整个反应过程可分为微波诱导阶段和催化氧化阶段,两个阶段的氧化过程均符合一级反应动力学规律.     

A multi-domain spectral method for non-Darcian mixed convection flow in a power-law fluid with viscous dissipation

The purpose of this study is to investigate non-Darcian mixed convection flow, heat and mass transfer in a non-Newtonian power-law fluid over a flat plate embedded in porous medium with suction and viscous dissipation and also is to demonstrate the application and utility of a recently developed multi-domain bivariate spectral quasi-linearisation method (MD-BSQLM) in finding the solutions of highly nonlinear differential equations. The flow is subject to, among other source terms, internal heat generation, thermal radiation and partial velocity slip. The coupled system of nonlinear partial differential equations are solved using a MD-BSQLM to find the fluid properties, the skin friction, as well as the heat and mass coefficients. We have presented selected results that give the significance of some system parameters on the fluid properties. This MD-BSQLM has not been used before in the literature to find the nature of the solutions of power-law fluids. Indeed, validation of this numerical method for general fluid flows, heat and mass transfer problems has not yet been done. This study presents the first opportunity to evaluate the accuracy and robustness of the MD-BSQLM in finding solutions of non-Newtonian fluids.     

Experimental investigation of mixed convection heat transfer of nanofluids in a circular microchannel with different inclination angles

Journal of Thermal Analysis and Calorimetry - In this study, the characteristics of mixed convection heat transfer of nanofluids in circular microchannels with 500 μm diameter were...     

Unsteady double-diffusive convection in a water-based Al2O3-nanofluid in a two-sided lid-driven porous cavity

A numerical investigation of the flow and behaviour of properties of a water-based Al₂O₃-nanofluid inside a two-sided lid-driven inclined non-uniformly heated and concentrated porous cavity is made in this paper. The focus of the study is on determining how the buoyancy ratio and the inclination angles influence the unsteady double-diffusive natural convection in a cavity filled with a porous medium, and with non-uniform boundary conditions. We further consider different nanoparticle volume fractions of the nanofluid. It is assumed that the left and right vertical walls are insulated, while the bottom wall is heated and concentrated non-uniformly and the top wall maintained at a constant cold temperature. The top and bottom walls move from left to right and right to left with constant speed, respectively. The governing equations are solved numerically using a staggered grid finite-difference method for streamlines, isotherms, iso-concentrations, average Nusselt number and average Sherwood number for various values of nanoparticle volume fraction, inclination angle and buoyancy ratio. The change in the flow, temperature and concentration profile patterns with respect to time is depicted and described. The results are compared with previously published work and excellent agreement has been obtained.