heat and mass transfer
nonlinear two-phase space
highly nonlinear problem
A new complex approach is proposed for mathematical modeling of multidimensional non-steady heat and mass transfer in composite materials under high-temperature heating, when all transfer properties are nonlinear. These problems are actual for aero- and spatial industry during last forty years.
In the composite materials loaded by high temperatures a small domain of pyrolysis of binding agents is observed, where binding agent is transformed to porous residue and pyrolysis gas filtering throw the porous media to the outer boundary under the pyrolytic pressure. The pyrolysis zone is moved by heat flows from outer media into composite structure with unknown velocity that can be defied by heat state of material. Thus, the complex model of heat and mass transfer in composite structure is combined from the next nonlinear particular models: binding agents’ physical and chemical pyrolyse, non-isothermal pyrolysis gases filtration, heat conduction considering filtration processes, non-steady pyrolysis zone’s boundaries motion and mass loss form the outer boundary.
Using the identified by author nonlinear principles of both binding agent destruction and pyrolysis gases filtration a new model of heat and mass transfer in two-phase anisotropic media is proposed and new economic and absolutely stable method of the complex problem’s numerical solution is proposed. Using the developed software many new results are obtained, for example, two-dimensional temperature fields in porous and non-destructed phases, two-dimensional non-steady moving boundaries of pyrolysis zone, pressure and velocity fields for pyrolysis gases. Some guidelines to use these methods are formulated