LIMIT THERMAL FLUXES AND THERMAL STRESSES IN POROUS COATINGS OF A HEAT-ENERGY INSTALLATION
The methods and devices for power plants and the creation of scientific methods have been developed. Investigations of the limiting heat fluxes in metallic and poorly heat-conducting porous structures operating under the combined action of gravitational and capillary forces and cooling various devices of thermal power plants are carried out. Based on the solution of the problem of thermoelasticity and experimental data, the mechanism of destruction of metal steam generating surfaces and poorly heat-conducting coatings of small porosity made of natural mineral media (granite) is described. On the basis of the analogy of the phenomena, the dependences of the heat fluxes on the time of their action and the depth of penetration of temperature disturbances are revealed. Capillary-porous systems have high intensity, high heat transfer ability, reliability, compactness. The results of calculations and experiments showed that the maximum thickness of the particles that break off under the action of compression forces for coatings from granite is (0,25÷0,3)х10<sup>-2 </sup>m. Sections of compression curves that determine the separation of particles with dimensions greater than 0,3х10<sup>-2 </sup>m for large heat fluxes and short delivery times are screened by the melting curve, and in the case of small heat fluxes and significant time intervals, the expansion curve. The research is aimed at the creation of porous cooling systems from well- and poorly-heat-conducting materials.