Finite Element Analysis Of Piston Crown For B&W6S50ME-B Diesel Engine

The low speed two stroke marine diesel engine is developing continuously to long stroke, high pressure, low consumption, low emission, high adaptability, high automation and intelligent. MAN Company designs new ME-B type diesel engine to meet this development. Piston crown is one of the most important components of diesel engine, withstanding high thermal load, mechanical load and coupled load in procession of motion, which may bring piston breakage, scuffing of cylinder bore and piston ring sticking. The piston crown work reliability and durability is directly related to meet the design requirement. Based on the purpose, author uses large commercial finite element analysis software ANSYS to analyze the new ME-B piston crown under the thermal load, mechanical load and coupled load.In this thesis, author uses UG to establish the three-dimensional model of MAN B&W6S50ME-B9.2 piston crown and imported into ANSYS to mess. In imposing the boundary conditions, carried out the simulation. Firstly, using diesel engine indicator diagram and empirical formula to calculate the boundary temperature and heat transfer coefficient, which are the boundary conditions for getting the piston crown temperature field. Based on the temperature field, thermal stress is executed under steady operation condition. Secondly, calculate the mechanical stress. Finally, calculate the stress and strain distribution when thermal and mechanical load are coupled.Through the finite element analysis of piston crown, this thesis calculates the stress and strain distribution, finds the maximum stress and strain of piston crown and determines the risky parts which may provide help in diesel engine optimization and manufacturing.