EXPERIMENTAL DETERMINATION OF EFFECTIVENESS OF THERMAL INSULATION OF XPERIMENTAL DETERMINATION OF EFFECTIVENESS OF THERMAL INSULATION OF HEATING NETWORKS INVOLVING APPLICATION OF THIN-FILM COATINGS

Abstract

The purpose of the paper is experimental evaluation of thermal characteristics in a heat insulating structure with a thin fi lm coating applied onto the same, such as conductive heat transmission capacity, radiation and convection, assessment of the extent of infl uence of each component on reducing heat fl ux density. Experimental studies have been held on determination of thermal conductivity factor, integral factor of emissivity and air permeability of the heat insulating structure. Investigation of thermal conductivity of the heat insulating structure with a thin fi lm coating has been carried out using the method of continuous heat fl ux passing through a sample of heat insulating structure under study. Investigation of thermal radiation of the heat insulating structure with a thin film coating consisted in determining the integral emissivity factor by the radiation method. The air permeability of the heat insulating structure with a thin fi lm coating has been determined by a method based on establishing the time of passage of a certain amount of air through the sample at a known air pressure. The results are presented of the infl uence produced by the thin fi lm coating in the design of thermal insulation of pipelines of heat networks on reducing heat losses through reducing heat fl ow density. It is found that the greatest eff ect on reducing heat fl ow density is produced by air permeability of the thermal insulation material after application of the thin fi lm coating to its surface, which generally enhances the effi ciency and reliability of thermal insulation structures of pipelines in heat supply systems.