NUMERICAL MODELING OF RADIATION-CONVECTION HEAT TRANSFER FROM A HEATED OBJECT TO THE SURROUNDING ENVIRONMENT UNDER CONDITIONS OF FREE CONVECTION

Abstract

A known method of protecting heated objects from being recognized by optoelectronic devices that detect infrared radiation is to use screens over the heated objects that reduce the intensity of this radiation. Low-emissivity coatings with low emissivity coefficients are applied to the surface of such screens. Such a coating can be copper foil. To determine the effectiveness of this method of temperature masking of heated objects, numerical simulation of radiation-convection heat transfer of a heated horizontal plate with the environment, above which a textolite screen with copper foil on the surface is located, is performed. Numerical modeling is performed by the method of numerical solution of the system of equations of hydrodynamics and heat transfer. This system is supplemented by boundary conditions of the fourth kind, which take into account the presence of radiation heat flux on the surfaces of the plate and the screen. It is determined that the radiation heat flux on the outer surface of the screen under the conditions considered can be reduced by 6.7...7.48 times due to the copper foil coating. In this case, increasing the distance between the screen and the heated object contributes to the reduction of the radiation heat flux from the screen.