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 J?e0-684, but with fleece covering the trunk to a depth of 3.5 cm, Nu = 0.0112 °-875 when the mean radiative temperature of the coat was taken as ...

An empirical correlation for predicting the heat transfer coefficient for a cylinder under free convection, inclined at any arbitrary angle with the horizontal has been developed in terms of Nusselt number, Prandtl number and Grashof number. Available experimental data was used to determine the parameters for the proposed correlation. The proposed correlation predicts the available data well wi...

Abstract A gas-cooled nuclear reactor combined with a Brayton cycle shows promise as technology for high-power space power systems. Generally, helium–xenon gas mixture molecular weight of 14.5–40.0 g/mol is adopted the working fluid to reduce mass and volume turbomachinery. The Prandtl number mixtures this recommended mixing ratio may be low 0.2. As convective heat transfer closely related numb...

Analytical results are presented for a steady three-dimensional free convection flow in the stagnation point region over a general curved isothermal surface placed in a nanofluid. The momentum equations in x- and y-directions, energy balance equation, and nanoparticle concentration equation are reduced to a set of four fully coupled nonlinear differential equations under appropriate similarity ...

in this work a numerical study of thermal and fluid dynamics behavior of natural air convection in a square cavity in a laminar flow is presented, by finite volume method. the square cavity has two walls heated with different temperatures and two isolated walls. the numerical simulation is made up of several rayleigh numbers to . flow and isotherm lines are presented and analyzed. the numerical...

In this study, a numerical model was developed for prediction of Nusselt number in solar cavity receivers. Thermal oil and water were used as the working fluid. A dish concentrator with different shapes receiver, including hemispherical, cylindrical, cubical, investigated. The receiver studied under same operating conditions internal heat transfer coefficient correlation each receiver. system i...

The natural convection heat transfer of horizontal rectangle enclosures with different aspect ratios (A = 2:1 and A = 4:1) filled with Ag-Ga nanofluid (different nanoparticle volume fractions φ = 0.01, φ = 0.03, φ = 0.05 and radiuses r = 20 nm, r = 40 nm, r = 80 nm) at different Rayleigh numbers (Ra = 1 × 103 and Ra = 1 × 105) is investigated by a two-phase lattice Boltzmann model. It is found ...

A one-dimensional divergence of the monochromatic heat flux for wall-affected attenuating thingas, is developed from general considerations. Here Ebl. K~ cy and r, respectively denote the monochromatic values of the emissive power, absorption coefficient of gas, wall emissivity and optical thickness; , E, is the second exponential integ-ral, y the -4' coordinate normal to boundary. infinite geo...

This current work studies the heat transfer performance and entropy generation of natural convection in a nanofluid-filled U-shaped cavity. The flow behavior and heat transfer performance in the cavity are governed using the continuity equation, momentum equations, energy equation and Boussinesq approximation, and are solved numerically using the finite-volume method and SIMPLE C algorithm. The...