Search

In this paper, we investigate how the solutions vary when the relaxation parameter, the conductivity rate parameter, or the thermal conductivity parameter change in the case of the Moore-Gibson-Thompson heat equation. In fact, we prove that they can be controlled by a term depending upon the square of the variation of the parameter. These results concern the structural stability of the problem. We also compare the solutions of the MGT equation with the Maxwell-Cattaneo heat conduction equation and the type III heat equation (limit cases for the first two previous parameters) and we show how the difference between the solutions can be controlled by a term depending on the square of the limit parameter. This result gives a measure of the convergence between the solutions for the different theories. [ABSTRACT FROM AUTHOR]

One of the most critical tasks of modern energy is accumulating thermal energy due to the inefficient use of thermal energy during the underloading of power systems in which heat-accumulating materials are used. Therefore the paper studies the effect of alternating electric current on the heat-accumulating properties in a mixture based on Na2SO4·10H2O. It is established that the AC effect leads to an increase in the melt crystallization temperature of Na2SO4·10H2O and Na2S2O3·5H2O and also contributes to the return of heat. The selection of the treatment mode of the Na2SO4·10H2O–Na2S2O3·5H2O (50: 1 wt.) mixture by the AC was carried out. It was shown that the latent heat of melting of 329 kJ/kg is achieved at 500000 Hz frequency. [ABSTRACT FROM AUTHOR]