Numerical Simulation of Flow and Heat Transfer of Nanofluid around a Heated Square Cylinder (original) (raw)
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Procedia Technology, 2014
Numerical investigation of heat transfer phenomena over an isothermal cylinder, for low Reynolds number flow of nanofluid is presented. Conservation equation of mass, momentum and energy under steady state have been solved using finite volume method. Heat transfer characteristic and flow over the stationary cylinder has been studied for water based copper nano fluid with different solid fraction values. Local Nusselt number over the cylinder surface has been found to increase with increase in nano particle fraction as well as increase in flow strength, though, the physics behind the rise in two cases is entirely different. Local heat flux drops along the cylinder wall and increases with increase in nano particle fraction as well as Reynolds number. Neglecting buoyancy effect, flow separation angle is not affected by presence of nano particles in the base fluid.
International Journal of Heat and Mass Transfer, 2012
This paper investigates the buoyancy driven mixed convective flow and heat transfer characteristics of water-based nanofluid past a circular cylinder in cross flow using a SUPG based finite element method. Nano sized copper particles suspended in water is used with Prandtl number (Pr) = 6.2, and the range of solid volume fractions 0 6 / 6 25% are considered. Computations are carried out for the range of Reynolds number 80 6 Re 6 180. Effect of aiding and opposing buoyancy is bought about by considering two representative Richardson numbers of 1 and À1.
Numerical Investigation of Heat Transfer of Nanofluid Flow Past Two Cylinder in Tandem Arrangements
Third International Conference on Advances in Mechanical and Robotics Engineering- AMRE 2015, 2015
In this paper, numerical method is developed and simulations of flow and heat transfer of nanofluids is presented. The effect of nanoparticle volume fraction for the enhancement of heat transfer is examined for several sets of values of Reynolds numbers. The study is conducted for pure water and watercopper nanofliud. The study is carried out for Reynolds numbers of 100 and 150 and for volume fraction of nanoparticles of 0, 0.05, 0.10 and 0.15. The mean Nusselt numbers for front and rear cylinders are obtained. The obtained results indicated that the increase of nanoparticles volume fraction has a positive effect on the mean Nusselt number.
International Journal of Simulation Modelling, 2014
Forced convection heat transfer from a heated circular cylinder to incompressible water-based nanofluids in the steady cross-flow regime has been investigated numerically. The momentum and thermal energy differential equations have been solved by the standard finite volume method on the non-uniform Cartesian grid. The main objective of this study is to investigate the influence of the nanoparticles' volume fraction (0 % ≤ φ ≤ 10 %) on the heat transfer characteristics of water-based nanofluids over a wide range of base-fluid Reynolds number (1 ≤ Re bf ≤ 20). Accurate numerical results are presented in the form of the local and mean Nusselt number and the heat transfer enhancement. The results indicate clearly that the heat transfer characteristics are affected by the base-fluid Reynolds number, volume fraction and the thermo-physical properties of nanoparticles. Although those nanofluids reduce the mean Nusselt number values, they enhance the heat transfer rate.
Heat Transfer Enhancement in Combined Convection Around a Horizontal Cylinder Using Nanofluids
Journal of Heat Transfer, 2008
Heat transfer enhancement in combined convection around a rotating horizontal cylinder using nanofluids is presented. The transport equations are solved numerically using a second-order finite volume scheme. Water-based nanofluid containing various volume fractions of different types of nanoparticles is used. The nanoparticles used are Cu, Ag, Al 2 O 3 , and TiO 2 . In the region outside the plume, the Nusselt number increases by increasing the volume fraction of nanoparticles. However, in the plume region, the effect of the volume fraction of nanoparticles on the Nusselt number is less pronounced. Downloaded 28 Jul 2008 to 131.128.52.182. Redistribution subject to ASME license or copyright; see http://www.asme.org/terms/Terms\_Use.cfm
Springer, 2020
In this paper, the finite volume method is used to investigate the laminar forced convection of water-copper nanofluid between two porous horizontal concentric cylinders. The effects of Reynolds number, the volume fraction of nanoparticles, the geometry, and the porous medium porosity on heat transfer have been studied. The problem is investigated in two different geometries and Re = 10, 25, 50, 75,100, and volume fraction of nanoparticles 0, 0.2, 0.5, 2, and 5% that were related to Copper nanoparticles and the porous medium porosity of 0.5, 0.9. The results indicated that in each geometry, the corresponding Nusselt number increase in the porosity of 0.9 is greater than that of the case with the porosity of 0.5. The results show that the increase in the heat transfer coefficient in the second geometry is greater than the first geometry and in porosity 0.9 is greater than porosity 0.5. These increase values are 6 and 3%, respectively. The increase in the average temperature of the inner cylinder surface in the five mentioned Reynolds values and both geometries is investigated. This increase in temperature in Re = 10 is greater than other Reynolds numbers. The corresponding temperature increases of Re = 10, for the first and second geometries, are 1.8 and 2.2%, respectively. Investigation of the effects of volume fraction of nanoparticles on Nusselt number and heat transfer coefficient shows that both parameters increase by increasing in the volume fraction of nanoparticles. The results show that the increase in the volume fraction of nanoparticles causes the increase in average temperature of the surface. The results show that these increases of temperature that take place in the volume fractions of 0.5, 2, and 5% of nanoparticles are equal to 0.6, 1.14, and 2.3% and relative to the water, respectively.
2014
This study reports numerical simulation for 3D laminar forced convection of a nanofluid flow in horizontal annulus with constant heat flux at the outer cylinder will the inner cylinder is considered adiabatic. The numerical model is carried out by solving the governing equation of continuity, momentum and energy using take account for thee finite volume method, with the assistance of SIMPLER algorithm. The results shows that for the Reynolds numbers and Prandtl fixed, the dimensionless velocity profile for the laminar forced convection of a nanofluid consisting of water does not vary with the volume concentration of nanoparticles while the effect of the concentration of nanoparticles on the temperature of the mass is significant nanofluid. These results are consistent with those found in the literature. In general the use of nanofluid with a volume concentration of nanoparticles causes a increase in the coefficient of heat transfer by convection.
Numerical Investigation of Nanofluid Laminar Convective Heat Transfer through a Circular Tube
Numerical Heat Transfer, Part A: Applications, 2007
In this paper, the finite volume method is used to investigate the laminar forced convection of water-copper nanofluid between two porous horizontal concentric cylinders. The effects of Reynolds number, the volume fraction of nanoparticles, the geometry, and the porous medium porosity on heat transfer have been studied. The problem is investigated in two different geometries and Re = 10, 25, 50, 75,100, and volume fraction of nanoparticles 0, 0.2, 0.5, 2, and 5% that were related to Copper nanoparticles and the porous medium porosity of 0.5, 0.9. The results indicated that in each geometry, the corresponding Nusselt number increase in the porosity of 0.9 is greater than that of the case with the porosity of 0.5. The results show that the increase in the heat transfer coefficient in the second geometry is greater than the first geometry and in porosity 0.9 is greater than porosity 0.5. These increase values are 6 and 3%, respectively. The increase in the average temperature of the inner cylinder surface in the five mentioned Reynolds values and both geometries is investigated. This increase in temperature in Re = 10 is greater than other Reynolds numbers. The corresponding temperature increases of Re = 10, for the first and second geometries, are 1.8 and 2.2%, respectively. Investigation of the effects of volume fraction of nanoparticles on Nusselt number and heat transfer coefficient shows that both parameters increase by increasing in the volume fraction of nanoparticles. The results show that the increase in the volume fraction of nanoparticles causes the increase in average temperature of the surface. The results show that these increases of temperature that take place in the volume fractions of 0.5, 2, and 5% of nanoparticles are equal to 0.6, 1.14, and 2.3% and relative to the water, respectively.
Unconfined laminar nanofluid flow and heat transfer around a square cylinder
The momentum and forced convection heat transfer for a laminar and steady free stream flow of nanofluids past an isolated square cylinder have been studied numerically. Different nanofluids consisting of Al2O3 and CuO with base fluids of water and a 60:40 (by mass) ethylene glycol and water mixture were selected to evaluate their superiority over conventional fluids. Recent correlations for the thermal conductivity and viscosity of nanofluids, which are functions of particle volumetric concentration as well as temperature, have been employed in this paper. The simulations have been conducted for Pe = 25, 50, 100 and 200, with nanoparticle diameters of 30 and 100 nm and particle volumetric concentrations ranging from 0% to 4%. The results of heat transfer characteristics of nanofluid flow over a square cylinder showed marked improvement comparing with the base fluids. This improvement is more evident in flows with higher Peclet numbers and higher particle volume concentration, while the particle diameter imposes an adverse effect on the heat transfer characteristics. In addition, it was shown that for any given particle diameter there is an optimum value of particle concentration that results in the highest heat transfer coefficient.
energies, 2021
The present study deals with the numerical simulation of mixed convective heat transfer from an unconfined heated square cylinder using nanofluids (Al2O3-water) for Reynolds number (Re) 10–150, Richardson number (Ri) 0–1, and nanoparticles volume fractions (ϕ) 0-5%. Two-phase modelling approach (i.e., Eulerian-mixture model) is adopted to analyze the flow and heat transfer characteristics of nanofluids. A square cylinder with a constant temperature higher than that of the ambient is exposed to a uniform flow. The governing equations are discretized and solved by using a finite volume method employing the SIMPLE algorithm for pressure–velocity coupling. The thermo-physical properties of nanofluids are calculated from the theoretical models using a single-phase approach. The flow and heat transfer characteristics of nanofluids are studied for considered parameters and compared with those of the base fluid. The temperature field and flow structure around the square cylinder are visualized and compared for single and multi-phase approaches. The thermal performance under thermal buoyancy conditions for both steady and unsteady flow regimes is presented. Minor variations in flow and thermal characteristics are observed between the two approaches for the range of nanoparticle volume fractions considered. Variation in ϕ affects CD when Reynolds number is varied from 10 to 50. Beyond Reynolds number 50, no significant change in CD is observed with change in ϕ. The local and mean Nusselt numbers increase with Reynolds number, Richardson number, and nanoparticle volume fraction. For instance, the mean Nusselt number of nanofluids at Re = 100, ϕ = 5%, and Ri = 1 is approximately 12.4% higher than that of the base fluid. Overall, the thermal enhancement ratio increases with ϕ and decreases with Re regardless of Ri variation.