Abstract
A theoretical model was developed which can be used to describe the radiant heat transfer through semitransparent heat-insulating coatings (SHIC) — as selectively absorbing and scattering media in combustion chamber (CC) diesel engines. The main objective of this study is to analyze the transient temperature distributions in the semitransparent coating layers of walls of the CC by assuming transmittance and reflection of the heat-insulating coatings. The authors investigate the physical and mathematical models of radiative and conductive heat transfer. The paper presents a mathematical simulation of improved optical properties (reflectance, emittance); subsurface volumetric heating, temperature distributions for semitransparent heat-insulating layer with various thickness (changing transmittance) protecting metal substrate with different reflection and thermal physical properties. It has been shown decreasing of SHIC surface temperature in comparison with temperature of opaque heat-insulating coatings (OHIC).
Keywords: semitransparent heat-insulating coatings (SHIC), combustion chamber, lowheat- rejection diesel engine, scattering, absorption, transmittance, radiant heat exchange