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 ...

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...

    Given the need to increase the efficiency of heat transfer in thermal systems, especially systems using nanofluids in microscale and nanoscale heat transfer equipment ideas to improve their performance is very good.In present study, the flow and heat transfer of Water-Cu nanofluid in micro-tube with slip regime with constant wall heat flux numerically simulated with low Reynolds numbers. Sl...

A numerical simulation on confined impinging circular jet working with a mixture of water and Al2O3 nanoparticles is investigated. The flow is turbulent and a constant heat flux is applied on the heated plate. A two-phase mixture model approach has been adopted. Different nozzle-to-plate distance, nanoparticle volume concentrations and Reynolds number have been considered to study the thermal p...

Heat transfer and laminar air flow over a double backward-facing step numerically studied in this paper. The simulations was performed by using ANSYS ICEM for meshing process and using ANSYS fluent 14 (CFD) for solving. The k-ɛ standard model adopted with Reynolds number varied between 98.5 to 512 and three step height at constant heat flux (q=2000 W/m2). The top of wall and bottom of upstream ...