Measurements of the Nusselt number Nu and of properties of the large-scale circulation (LSC) for turbulent Rayleigh–Bénard convection are presented in the presence of rotation about a vertical axis at angular speeds 0 Ω <∼ 2 rad s−1. The sample chamber was cylindrical with a height equal to the diameter, and the fluid contained in it was water. The LSC was studied by measuring sidewall temperat...

In this paper, forced and free convection in the cavity is simulated numerically with complex boundary conditions. Temperature changes sinusoidally at the upper and right walls and the temperature of the other walls is kept at zero. The effects of Prandtl and Grashof numbers variations on flow patterns are surveyed. A wide range of materials, e.g. molten metals, gases, water, and coolant liquid...

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...

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 ...

The mixed convection heat transfer and fluid flow behaviors in a lid– driven square cavity filled with high Prandtl number fluids at low Reynolds number have been studied using Thermal Lattice Boltzmann Method (TLBM). The LBM has built up on the D2Q9 model called the Lattice-BGK (Bhatnagar–Gross–Krook) model. The Lattice Boltzmann momentum and energy equations are considered simultaneously to s...

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...