## THERMAL SCIENCE

International Scientific Journal

### Thermal Science - Online First

online first only
### Axisymmetric stagnation-point flow and heat transfer of nano-fluid impinging on a cylinder with constant wall heat flux

**ABSTRACT**

The steady-state, viscous flow and heat transfer of Nano-fluid in the vicinity of an axisymmetric stagnation point of a stationary cylinder with constant wall haet flux is investigated. The impinging free-stream is steady and with a constant strain rate k¯. Exact solution of the Navier-Stokes equations and energy equation are derived in this problem. A reduction of these equations is obtained by use of appropriate transformations introduced in this research. The general self-similar solution is obtained when the wall heat flux of the cylinder is constant. All the solutions above are presented for Reynolds numbers Re=k¯a2/2υf ranging from 0.1 to 1000, selected values of heat flux and selected values of particle fractions where is cylinder radius and is kinematic viscosity of the base fluid. For all Reynolds numbers, as the particle fraction increases, the depth of diffusion of the fluid velocity field in radial direction, the depth of the diffusion of the fluid velocity field in z-direction, shear-stresses and pressure function decreases. However, the depth of diffusion of the thermal boundary layer increases. It's clear by adding nanoparticles to the base fluid there is a significant enhancement in Nusselt Number and heat transfer.

**KEYWORDS**

PAPER SUBMITTED: 2017-11-24

PAPER REVISED: 2018-02-04

PAPER ACCEPTED: 2018-02-06

PUBLISHED ONLINE: 2018-03-04

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