Natural convection heat transfer in corrugated annuli with H2O-Al2O3 nanofluid

Abstract

The present work includes a numerical study of natural convection heat transfer in symmetrical and unsymmetrical corrugated annuli filled with H 2 O-Al 2 O 3 nanofluid. In this study, higher and lower temperatures were kept constant at inner and outer cylinders of the annulus; respectively. Eight mathematical models with an aspect ratio of 1.5 were developed to find the best model giving the highest heat transfer rates. The stream-vorticity formulation in curvilinear coordinates was used to solve the governing equations of heat transfer and fluid motion. The influences of Rayleigh number. ðð10 3 Ra 10 6 Þ and volume fraction of nanoparticles. (0 ϕ 0:25Þ on isotherms, streamlines, local and average Nusselt numbers on the inner and outer cylinder were investigated. The results show that the heat transfer rate is significantly increased with an increase in nanoparticles volume fraction and Rayleigh number. The activity of the heated surface is increased with an increase in the undulation number, but the flow motion tends to be most difficult in the spaces between active undulation walls. Moreover, the heat transfer rates in unsymmetrical annuli are relatively higher than the rates in the symmetrical annuli. There are no evident changes in isotherms with an increase in the nanofluid volume fraction. Correlations for the mean Nusselt number on the inner and outer walls of annulus were deduced as a function of Rayleigh number and nanoparticles volume fraction for eight models with an accuracy range of 8-15 %.

Mixed convection in sinusoidal lid driven cavity with non-uniform temperature distribution on the wall utilizing nanofluid

“…The thermo-physical properties of the nano-fluid are given as shown in Table 1 [ 38 ]. Also, for the nanofluid properties are estimated as follows in Table 2 [ 16 ].…”

“…Also, for the nanofluid properties are estimated as follows in Table 2 [ 16 ].…”

“…During nanofluid natural convection case the buoyancy driven force is dominate, where many investigations in this case with different shapes and boundary conditions [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. There are many of applications of mixed convection in the practical engineering such as cooling of electronic equipment, heat exchangers design, and heat sinks inside channel [ 17 , 18 ].…”

Heat transfer and lubrication performance of palm oil-Al2O3 nanofluid compared to traditional cutting fluid

“…Uma et al [17] developed an eco-friendly cutting fluid to promote cleaner and more efficient MQL machining and found that the thermal conductivity and viscosity increased with the mass fraction of nanoparticles. Alumina nanofluid was evaluated as a thermo-fluid with different volume fractions to observe the heat transfer enhancement under several conditions [18][19][20]. In the study of the influence of MQL with Al 2 O 3 nanoparticles on the milling processes of AISID3 steel, it was found that surface roughness decreased by approximately 0.5 mm and improved by nearly 25% [21].…”

An Efficient Numerical Simulation of 2D Natural Convection in an Inclined Cavity with Internal Heat Generation Using Differential Quadrature Method

“…The An Efficient Numerical Simulation of 2D Natural Convection Israa ALESBE et al http://wjst.wu.ac.th effect of the inner square cylinders' positions, sides-ratios, and sizes on radiative and convective heat transfers was discovered to be important. In corrugated annuli filled with nanofluid, a numerical natural convection heat transfer was investigated by Aljabair et al [19]. Eight mathematical models with an aspect ratio of 1.5 were used to find the best model with the highest heat transfer rates.…”