Numerical determination of the velocity fields of the working medium in the combustion chamber of a marine high-speed diesel engine
Modern trends in the development of marine diesel engines are associated primarily with the improvement of their energy and environmental characteristics. This gives rise to a number of problems, the most important of which is an increase in the combustion intensity. High local heat fluxes on the surfaces of the cylinder head, piston and liner are one of the main reasons that reduce the operational reliability of boosted marine diesel engines. The reliability of the calculated estimate of the thermal and stress-strain state of parts that form the combustion chamber is mainly determined by the correctness of setting the local boundary conditions from the part of the working medium. Taking into account that the share of convective heat flux in the total heat exchange reaches, on average, 60 - 70% for a working cycle, it becomes obvious the urgency of developing reliable computational and theoretical methods for determining the velocity fields of the working medium in the combustion chamber of marine diesel engines. The purpose of this article is to further improve the mathematical model of local convective heat transfer in the combustion chamber of a high-speed marine diesel engine. It is shown that the external flow of the working medium in the combustion chamber can be described by the Euler equations. The velocity fields of the working medium as a function of the angle of rotation of the crankshaft obtained by the numerical method are shown. Isotherms and isobars of the working medium are given, which allow a more in-depth analysis of the physics of the convective heat transfer process in the combustion chamber of a high-speed marine diesel engine.