Investigation of unsteady heat transfer in a porous medium of a discontinuous heater

This paper presents the results of determining the features of heat transfer on the example of a discontinuous heat exchanger with ball filling, used to generate a high-enthalpy flow. In the first part, we developed a one-dimensional mathematical model (an improved model of Schumann) unsteady heat transfer in a porous medium taking into account heat wall heater cooperage. An analytical solution is found in the quadratures of the system of partial differential equations. The second part of the paper is devoted to numerical modeling. The influence of empirical coefficients on heat transfer was revealed. The results of numerical simulation were compared with the results of one-dimensional mathematical model. As a result of the computational study, the correspondence and differences in thermal and hydrodynamic processes using one-dimensional differential models and numerical modeling are established. A significant influence of empirical coefficients on the qualitative and quantitative nature of the temperature distribution of the gas and the solid matrix over time was revealed. The correspondence of results between two approaches is established: the solution of differential equations and numerical modeling. On the basis of the analysis the applicability of mathematical models of different levels for solving a certain class of problems is established.