Thermal Analysis of a Diesel Piston and Cylinder Liner using the Inverse Heat Conduction Method

Martin Gonera, Olle Sandin (Chalmers University)

CHALLENGE - This Master’s thesis developed a thermal analysis model of a diesel piston that is used in Volvo Cars engines. A thermal analysis model of the piston enhances the possibilities to determine the complete thermal loads of the car engine and can be used as a boundary condition when performing combustion CFD-simulation. It may also serve as an aid in piston design.

SOLUTION - The thermal analysis is solely conducted through FE-analysis and the results of the FE-analysis are validated through previous measured thermal test data by the piston manufacturer Mahle. The softwares used for the thermal analysis are MATLAB, Abaqus, ANSA and modeFRONTIER. The solution strategy consists of four steps: first, the calculation of initial piston boundary heat transfer coefficients (HTC)s according to analytical methods, empirical correlations or assumed from experience. Second step consists in performing an HTC parameter calibration with the in-house developed MATLAB program on a 2D axisymmetrical piston FE-model while the third step involves the HTC parameter calibration on a 3D diesel piston FE-model with modeFRONTIER. The fourth step linearly interpolates the HTCs between the calibrated load cases to construct a complete thermal analysis piston model.



BENEFITS - The results from the validations was that, for the intended engine load case span, the piston thermal analysis gave accurate results in terms of the piston structure temperature field and its surface heat flux. Results indicate excellent resemblance to the original analysis results, therefore, the element heat flux per unit area mapping methodology was considered to be feasible.