Multilayered Semitransparent and Opaque Heat-Insulating Coatings for Diesel Combustion Chamber

Heat-insulating coatings (HIC) being used in automotive industry for thermal insulation of thermally highly loaded components of combustion chamber (CC) are usually semitransparent (SHIC) for radiation of red-hot soot particles. The paper presents physical and mathematical models of radiation and conductive heat transfer and solution methods for multilayered scattering and absorbing coating. Calculations of radiation field are carried out by means of the method of moments and defined by the solution of differential equation system for moments of radiant intensity. The analysis is assumed to be without any soot layer on semitransparent one for this preliminary investigation. It allows to simulate temperature distributions for SHIC with internal radiant source above substrate with different reflection for operating conditions in CC of high-speed diesel engines (cyclic heating). The improved distributions of temperature due to absorption of volumetric radiant heat inside the top layer of semitransparent heat-insulating coatings are compared with traditional opaque HIC. The practical importance of the given research is discussed.