OPTIMIZATION OF THE THERMAL STATE OF THE CYLINDER SLEEVE OF THE MEDIUM-ROTATION MARINE DIESEL ENGINE

Abstract

The calculation study is based on the results of long-term experimental studies of the thermal state of a cylindrical sleeve of the middle-speed marine diesel 6CHN26 / 34, which were carried out at the Department of DVS NTU "KhPI" in the 80s under the guidance of prof. Ye. I. Tretyak. The problem of marine diesel engines of this design was a significant supercooling of the liner, which, in turn, worsened the lubrication conditions in the liner-piston coupling, due to the increased viscosity of the engine oil. Optimization of the thermal state provided for the achievement of a certain temperature profile along the working surface of the liner, such that it is possible to minimize friction costs while maintaining the viscosity of the oil within certain limits. The carried out experimental studies confirmed the possibility of practical solution of this problem.In order to improve the technical and economic parameters of the ship's diesel engine, this design study sets the task of developing a mathematical model for the heat-stressed state of a cylindrical sleeve, its refinement on the basis of these experimental studies, and the development of practical recommendations for optimizing the temperature condition of the sleeve.The analysis of publications on the research subjects, in particular, the works of prof. E.I. Tretyak, the features of specifying the boundary conditions of the heat conduction problem for design options are analyzed in detail. In particular, it has been proposed to limit the cooling of the liner only by local cooling of its upper belt. To equalize the temperatures along the height of the sleeve, it is also proposed to apply a heat-insulating enamel layer on the lower part of the sleeve. The heat-stressed state of the sleeve is analyzed using the finite element method.