Limits...
Numerical investigation of Al2O3/water nanofluid laminar convective heat transfer through triangular ducts.

Zeinali Heris S, Noie SH, Talaii E, Sargolzaei J - Nanoscale Res Lett (2011)

Bottom Line: In this article, for considering the presence of nanoparticl: es, the dispersion model is used.Numerical results represent an enhancement of heat transfer of fluid associated with changing to the suspension of nanometer-sized particles in the triangular duct.The results of the present model indicate that the nanofluid Nusselt number increases with increasing concentration of nanoparticles and decreasing diameter.

View Article: PubMed Central - HTML - PubMed

Affiliation: Chemical Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran. zeinali@ferdowsi.um.ac.ir.

ABSTRACT
In this article, laminar flow-forced convective heat transfer of Al2O3/water nanofluid in a triangular duct under constant wall temperature condition is investigated numerically. In this investigation, the effects of parameters, such as nanoparticles diameter, concentration, and Reynolds number on the enhancement of nanofluids heat transfer is studied. Besides, the comparison between nanofluid and pure fluid heat transfer is achieved in this article. Sometimes, because of pressure drop limitations, the need for non-circular ducts arises in many heat transfer applications. The low heat transfer rate of non-circular ducts is one the limitations of these systems, and utilization of nanofluid instead of pure fluid because of its potential to increase heat transfer of system can compensate this problem. In this article, for considering the presence of nanoparticl: es, the dispersion model is used. Numerical results represent an enhancement of heat transfer of fluid associated with changing to the suspension of nanometer-sized particles in the triangular duct. The results of the present model indicate that the nanofluid Nusselt number increases with increasing concentration of nanoparticles and decreasing diameter. Also, the enhancement of the fluid heat transfer becomes better at high Re in laminar flow with the addition of nanoparticles.

No MeSH data available.


Related in: MedlinePlus

Comparison between nanofluid and pure fluid heat transfer.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3211232&req=5

Figure 4: Comparison between nanofluid and pure fluid heat transfer.

Mentions: Figure 4 shows the average Nusselt numbers versus Re for Al2O3/water nanofluid (with 1.0% volume concentration of 10-nm Al2O3 nanoparticles) and pure water. As shown in Figure 4, the slope of Nu versus Re is greater for Al2O3/water compared with pure water, which means a considerable enhancement of heat transfer due the addition of nanoparticles to the base fluid. For example, at Re = 1500, Nusselt number of water is increased from 3.47 to 4.22 with the addition of Al2O3 nanoparticles. It is known that the addition of Al2O3 nanoparticles will increase the thermal conductivity of the working fluid and hence the heat transfer capability [5-12]. Besides, the nanoparticles with dispersion effect and Brownian motion hit the tube wall and absorb heat, and then mix back with the bulk of the fluid to cause a better heat transfer. The presence of nanoparticles inside the fluid causes the collision between the heating surface and the particles, thereby producing higher heat transfer coefficients. This means that the addition of nanoparticles to fluid changes the flow structure so that besides the increase in thermal conductivity, dispersion and fluctuation of nanoparticles, especially near the tube wall, lead to the increase in the energy exchange rates and augment the heat transfer rate between the fluid and the tube wall [22,23]. Moreover, the local Nu in fluid flow inside channel is related to the thickness of the thermal boundary layer, and a decrease in thermal boundary-layer thickness increases local Nu. One of the possible mechanisms responsible for the exhibition of the thermal boundary-layer thickness decrement by nanofluid is the migration of the nanoparticles due to shear action, Brownian motion, and the viscosity gradient in the cross section of the channel [47].


Numerical investigation of Al2O3/water nanofluid laminar convective heat transfer through triangular ducts.

Zeinali Heris S, Noie SH, Talaii E, Sargolzaei J - Nanoscale Res Lett (2011)

Comparison between nanofluid and pure fluid heat transfer.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211232&req=5

Figure 4: Comparison between nanofluid and pure fluid heat transfer.
Mentions: Figure 4 shows the average Nusselt numbers versus Re for Al2O3/water nanofluid (with 1.0% volume concentration of 10-nm Al2O3 nanoparticles) and pure water. As shown in Figure 4, the slope of Nu versus Re is greater for Al2O3/water compared with pure water, which means a considerable enhancement of heat transfer due the addition of nanoparticles to the base fluid. For example, at Re = 1500, Nusselt number of water is increased from 3.47 to 4.22 with the addition of Al2O3 nanoparticles. It is known that the addition of Al2O3 nanoparticles will increase the thermal conductivity of the working fluid and hence the heat transfer capability [5-12]. Besides, the nanoparticles with dispersion effect and Brownian motion hit the tube wall and absorb heat, and then mix back with the bulk of the fluid to cause a better heat transfer. The presence of nanoparticles inside the fluid causes the collision between the heating surface and the particles, thereby producing higher heat transfer coefficients. This means that the addition of nanoparticles to fluid changes the flow structure so that besides the increase in thermal conductivity, dispersion and fluctuation of nanoparticles, especially near the tube wall, lead to the increase in the energy exchange rates and augment the heat transfer rate between the fluid and the tube wall [22,23]. Moreover, the local Nu in fluid flow inside channel is related to the thickness of the thermal boundary layer, and a decrease in thermal boundary-layer thickness increases local Nu. One of the possible mechanisms responsible for the exhibition of the thermal boundary-layer thickness decrement by nanofluid is the migration of the nanoparticles due to shear action, Brownian motion, and the viscosity gradient in the cross section of the channel [47].

Bottom Line: In this article, for considering the presence of nanoparticl: es, the dispersion model is used.Numerical results represent an enhancement of heat transfer of fluid associated with changing to the suspension of nanometer-sized particles in the triangular duct.The results of the present model indicate that the nanofluid Nusselt number increases with increasing concentration of nanoparticles and decreasing diameter.

View Article: PubMed Central - HTML - PubMed

Affiliation: Chemical Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran. zeinali@ferdowsi.um.ac.ir.

ABSTRACT
In this article, laminar flow-forced convective heat transfer of Al2O3/water nanofluid in a triangular duct under constant wall temperature condition is investigated numerically. In this investigation, the effects of parameters, such as nanoparticles diameter, concentration, and Reynolds number on the enhancement of nanofluids heat transfer is studied. Besides, the comparison between nanofluid and pure fluid heat transfer is achieved in this article. Sometimes, because of pressure drop limitations, the need for non-circular ducts arises in many heat transfer applications. The low heat transfer rate of non-circular ducts is one the limitations of these systems, and utilization of nanofluid instead of pure fluid because of its potential to increase heat transfer of system can compensate this problem. In this article, for considering the presence of nanoparticl: es, the dispersion model is used. Numerical results represent an enhancement of heat transfer of fluid associated with changing to the suspension of nanometer-sized particles in the triangular duct. The results of the present model indicate that the nanofluid Nusselt number increases with increasing concentration of nanoparticles and decreasing diameter. Also, the enhancement of the fluid heat transfer becomes better at high Re in laminar flow with the addition of nanoparticles.

No MeSH data available.


Related in: MedlinePlus