an investigation on the thermal performance of the soil as geothermal heat energy storage medium has been conducted. the thermal characteristics of the soil storage and the heat transfer from a heat exchanger in the soil, surrounding and bottom surface will be discussed. this investigation forms a contribution to a project to realize such storage to be charged from a solar heating system. this ...

In the Theory of Heat Radiation, Max Plank [1959] states that “so far as their physical properties are concerned, heat rays are identical with light rays of the same wavelength”. His book, which contains much of the basis upon which modern radiation heat transfer is based, does not consider the phenomenon of diffraction “on account of its complicated nature”. Plank goes on to say “[i]t will be ...

An optimal control problem for a nonlinear steady-state heat transfer model accounting for heat radiation effects is considered. The problem consists in minimization of a given cost functional by controlling the sources in the heat equation. The solvability of this control problem is proved, optimality conditions are derived, and an iterative algorithm for solving the optimal control problem is...

Two-dimensional numerical study of flow and temperature fields for laminar natural convection and radiation in the inclined cavity is performed in the present work. The walls of the square cavity are assumed kept at constant temperatures. An absorbing, emitting, and scattering gray medium is enclosed by the opaque and diffusely emitting walls. The set of governing equations, including conservat...

In order to improve the efficiency and rate of heat transfer in heat exchangers, various techniques such as increasing the heat transfer coefficient are proposed. This study is devoted to the investigation of heat transfer coefficient variations due to the addition of CuO, TiO2 and CuO/TiO2 nanoparticles into a shell and tube heat exchanger. CuO/TiO2 nanocomposite was synthesized using mechanic...

Abstract The paper considers the particular case of intensive radiation heat transfer in system consisting a human body and cryocabin walls cryosauna. Calculations for three models have been made, namely, human-vertical wall, which is arranged parallel to human, positioned at certain angle, human-cryosauna. Analytical calculations are compared with Ansys-bassed numerical calculations. impact th...

We have analyzed the effects of variable heat flux and internal heat generation on the flow and heat transfer in a thin film on a horizontal sheet in the presence of thermal radiation. Similarity transformations are used to transform the governing equations to a set of coupled nonlinear ordinary differential equations. The obtained differential equations are solved approximately by the homotopy...

The current article has investigated unsteady convective flow for MHD non-Newtonian Powell-Eyring fluid embedded porous medium over inclined permeable stretching sheet. We have pondered the thermophoresis parameter, chemical reaction, variable thermal conductivity, Brownian motion, variable heat source and variable thermal radiation in temperature and concentration profiles. Using similar trans...

in order to examine the laminar convective heat transfer of nanofluid, experiments carried out using silver-oil nanofluid in a concentric annulus with outer constant heat flux as boundary condition. silver-oil nanofluid prepared by electrical explosion of wire technique and observed no nanoparticles agglomeration during nanofluid preparation process and carried out experiments. the average size...