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A computational analysis of convective energy transport of water-based nanosuspension having variable thermal properties has been performed using finite difference method. The considered square cavity includes cold vertical walls and adiabatic horizontal boundaries. The local heater of periodic thermal production is placed on the lower border of the domain. The working fluid is water with copper oxide nanoparticles of low concentration. Control differential equations with initial and boundary conditions have been written using non-dimensional stream function, vorticity and temperature. The resulting nonlinear partial differential equations with associated boundary conditions are solved using the finite difference methodology on a uniform calculation mesh. The analyzed control parameters including volumetric heat generation frequency, initial fraction of nanoparticles, heater location and time have been studied. The physics of the problem is well-explored for the embedded material parameters through tables and graphs. The obtained data have shown that the volumetric thermal production frequency of the source and the initial concentration of nanoparticles have the greatest influence on the heat transfer performance. The energy source temperature can be reduced by up to 20% by varying the characteristics of the source and nanosuspension. [ABSTRACT FROM AUTHOR]

Convective heat transfer is a major phenomenon in different technical and natural systems. This process can be found in enclosures under the different temperature distributions at bounded walls. In this research, the thermogravitation energy transport of a non-constant viscosity medium inside a 3D region under the non-uniform or uniform temperature profile at one of the vertical walls is addressed. The opposite border is at a low constant temperature, and the remaining borders are well insulated. The control equations with the border restrictions are reduced into a non-dimensional form and then integrated by the finite difference procedures. The control characteristics are the Rayleigh number and viscosity changeable magnitude. The impacts of these characteristics on the energy transference and flow structures are studied. [ABSTRACT FROM AUTHOR]

Cooling of heat-generating elements is a challenging problem in engineering. In this article, the transient free convection of a temperature-dependent viscosity liquid inside the porous cavity with copper radiator and the heat-generating element is studied using mathematical modeling techniques. The vertical and top walls of the chamber are kept at low constant temperature, while the bottom wall is kept adiabatic. The working fluid is a heat-conducting liquid with temperature-dependent viscosity. A mathematical model is developed based on dimensionless stream function, vorticity, and temperature variables. The governing properties are the variable viscosity, geometric parameters of the radiator, and size of thermally insulated strip on vertical surfaces of the cavity. The effect of these parameters on the energy transport and circulation patterns are analyzed numerically. Based on the numerical results obtained, recommendations are given on the optimal values of the governing parameters for the effective operation of the cooling system. It is shown that the optimal number of radiator fins for the cooling system configuration under consideration is 3. In addition, the thermal insulation of the vertical walls and the increased thickness of the radiator fins have a negative effect on the operation of the cooling system. [ABSTRACT FROM AUTHOR]