the volumetric expansion coefficient has an importance in determination of the free convection heat transfer coefficient. the buoyant force in the fluid which is the result of the variation of fluid density with temperature, is proportional to this expansion coefficient, b. this coefficient of b varies with temperature and it is important to understand under what conditions it should be evaluat...

The enhancement of heat transfer by an electric field to a spherical droplet translating at intermediate Reynolds number is numerically investigated using a finite volume method. Two heat transfer limits are considered. The first limit is the external problem where the bulk of the resistance is assumed to be in the continuous phase. Results show that the external Nusselt number significantly in...

Natural convection heat transfer has many applications in different fields of industry; such as cooling industries, electronic transformer devices and ventilation equipment; due to simple process, economic advantage, low noise and renewed retrieval. Recently, heat transfer of nanofluids have been considered because of higher thermal conductivity coefficient compared with those of ordinary fluid...

In this paper, simulation of natural convection heat transfer from a confined isothermal horizontal elliptic tube based on artificial neural network is presented. The experimental work with changing of all variables is time consuming and expensive and usually has problems associated with it. Experimental data used for the neural network was obtained by a Mach-Zehnder interferometer. In this stu...

This article presents numerical simulations of conjugated heat transfer in a fouled channel with a moving depositing front. The depositing front separating the fluid and the deposit layer is captured using the level-set method. Fluid flow is modeled by the incompressible Navier-Stokes equations. Numerical solution is performed on a fixed mesh using the finite volume method. The effects of Reyno...

A new model to calculate heat eddy diffusivity in separating and reattaching flows based on modification of constant Prt is proposed. This modification is made using an empirical correlation between maximum Nusselt number and entrance Reynolds number. The model includes both the simplicity of Prt=0.9 assumption and the accuracy of two-equation heat-transfer models. Furthermore, an appropriate l...

The steady-state fully-developed laminar flow of non-Newtonian power-law fluids is examined in a circular microchannel with slip boundary condition and under an imposed constant wall heat flux. Effects of slip as well as the hydrodynamic and thermal key parameters on heat transfer and entropy generation are investigated. The results reveal that increasing the Brinkman number and the flow behavi...

We investigate entropy generation in unsteady three-dimensional axisymmetric MHD nanofluid flow over a non-linearly stretching sheet. The flow is subject to thermal radiation and a chemical reaction. The conservation equations were solved using the spectral quasi-linearization method. The novelty of the work is in the study of entropy generation in three-dimensional axisymmetric MHD nanofluid a...

A model sheep, made from metal cylinders and hemispheres, was heated electrically. Heat loss by forced convection in a wind tunnel was analysed in terms of the dependence of the Nusselt number (Nu) on Reynolds number (Re). For a bare trunk Nu = 0.095 Re0.684, but with fleece covering the trunk to a depth of 3.5 cm, Nu = 0.0112 Re0.875 when the mean radiative temperature of the the coat was take...