Analysis and Optimisation of Thermo-Mechanical Coupling Load of Cylinder Head Considering Fluid-Structure Interaction for a Marine High-Power Diesel Engine

Abstract

A one-dimensional model of the diesel engine working process was established, and thermal boundary conditions of gases contacting with a cylinder head were determined by comparing them with the results of a routine test. A fluid-structure interaction model between the cooling water and cylinder head passages was established in which boundary conditions of cooling water were obtained by computational fluid dynamics analysis. Simultaneously, considering the pressure mechanical load in the cylinder, temperature and the stress distribution of the cylinder head were analysed by the model with a thermo-mechanical coupling load. The model was validated using the temperature hardness plug method. Four parameters of intake valve opening, exhaust valve opening, fuel supply beginning, and compression ratio were selected as influencing factors, and the thermo-mechanical coupling load of the cylinder head was optimised by the Taguchi and analysis of variance method subsequently. The study indicates that the error of the calculation model for the cylinder head’s thermal-mechanical coupling load is within ±1.5%, and the proportion of the thermal stress in the cylinder head thermal-mechanical coupling stress is above 90%. The fuel supply beginning has the greatest influence on the thermal load of the cylinder head. Based on the optimisation methods within the required power range, the maximum temperature and maximum thermo-structural coupling stress of the cylinder head are decreased by about 10.05 K and 7.13 MPa in the nose bridge area, respectively.

Modernization of the Mechanical Fuel System of a Diesel Locomotive Engine through Physical and Numerical Modeling

“…In particular, it was found that NOx emissions decreased with increasing hole diameters. The same data for another engine can be found in [7,18,41]. The effect of the hole diameter on the smoke of the exhaust gases does not have a pronounced tendency (there is a complex regularity characteristic of this type of engine).…”

“…It was shown in [14,15] that careful tuning of the fuel system can lead to an increase in efficiency up to 19% and a decrease in hydrocarbon emissions up to 60% and carbon monoxide up to 64% when the diesel engine operates at low loads. Moreover, the level of gas-dynamic noise [16,17] and the strength of parts in the combustion chamber depend on perfecting the fuel supply process [18,19]. This once again underlines the importance of a detailed study on mixture formation and combustion in diesel ICEs of various sizes and purposes.…”