## Abstract

An analysis is carried out to study the convective heat transfer in a nanofluid flow over a stretching surface. In particular, we focus on Ag-water and Cu-water nanofluids, and investigate the effects of the nanoparticle volume fraction on the flow and heat transfer characteristics under the influence of thermal buoyancy and temperature dependent internal heat generation or absorption. The numerical results indicate that an increase in the nanoparticle volume fraction will decrease the velocity boundary layer thickness while increasing the thermal boundary layer thickness, even in the presence of free convection currents and internal heat generation. Meanwhile, the presence of nanoparticles results in an increase in the magnitude of the skin friction along the surface and a decrease in the magnitude of the local Nusselt number. Such effects are found to be more pronounced in the Ag-water solution than in the Cu-water solution; indeed, the Ag-water solution decreases the boundary layer thickness more than that of the Cu-water solution.

Original language | English |
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Pages (from-to) | 843-851 |

Number of pages | 9 |

Journal | International Journal of Thermal Sciences |

Volume | 50 |

Issue number | 5 |

DOIs | |

Publication status | Published - 2011 May |

### Bibliographical note

Funding Information:The authors appreciate the comments of the reviewers, which have lead to definite improvement in the paper. K. V. Prasad expresses his grateful thanks to DST authorities for providing with the financial support through BOYSCAST fellowship. C. Lee acknowledges the support of the WCU program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology R31-2008-000-10049-0 . a 0 , a 1 , b 0 , b 1 constants used in Equation (3.2) A , b constants used in Equation (2.4) C p specific heat at constant pressure C f skin friction f dimensionless stream function g acceleration due to gravity K thermal conductivity l characteristic length M confluent hypergeometric function used in Equation (3.2) Nu Nusselt number Pr Prandtl number Q volumetric rate of heat source/sink Re x local Reynolds number T temperature T w temperature of the plate T ∞ ambient temperature U stretching linear velocity u , v velocity components in the x and y directions x , y Cartesian coordinates

## All Science Journal Classification (ASJC) codes

- Condensed Matter Physics
- Engineering(all)