3D Numerical Study of Piston Head Design and Cooling Gallery Position Effects on the Thermal Analysis of a Marine Diesel Engine Piston

摘要

The main objective of this study is to investigate the effect of design variables on numerical thermal analysis of a marine diesel engine piston. Two different design variables are considered in this work. The first design variable to be investigated is piston head geometry and the effects of its modification on temperature distribution of a marine diesel engine piston are studied. Three different cases are investigated and the first case is taken for a bowl piston head which is considered the reference case. For second and third cases, a flat piston head and a domed piston head are studied. The numerical thermal analysis is performed for these three cases and the results show that flat top piston is less affected by the combustion with maximum temperature range of 714.86 K-679 K. On the other hand, the results show that domed top piston is exposed to the highest level of temperature ranging from 727.89 K to 690.57 K. The second design variable studied is cooling gallery position and the effect of its axial movement on temperature distribution. Two positions in the axial direction are taken which are obtained by moving the cooling gallery in increment of 3 mm axially towards the piston head in each case. Results of numerical thermal analysis show that the nearer the cooling gallery to the piston head surface, the lesser is the piston surface temperature. It is also observed that temperature range of referenced bowl top piston is decreased from 713.91 K -678.55 K to 708.4 K-673.38 K when oil cooling gallery is moved by increment of 6 mm axially towards piston head