Radiative Heat Transfer in the Combustion Chamber of a Diesel Engine

Abstract

Radiation is considered to be an important mode of heat transfer in diesel engines. It is mainly caused by a presence of soot particles in combustion gases. Spatial distribution of radiative heat flux on walls of the combustion chamber can be an important factor of thermal load of some parts of the engine. The paper presents a numerical method used for solution of integral equations resulting from mathematical description of variation of radiative heat flux on the walls of the combustion chamber. The charge in the chamber has been divided into the burned and the unburned zones. Shape and volume of the burned zone as well of the combustion chamber are varying according to variation in a crank angle during the whole combustion process. Comparison between numerical results obtained for opaque and semi-transparent burned zone is made. Influence of a degree of the burned zone transparency, the crank angle value and wall emissivity variation on the radiative heat flux distribution on different parts of the chamber surface has been presented.