Thermal and Structural Analysis of Functionally Graded NiCrAlY/YSZ/Al ₂ O ₃ Coated Piston

Functionally Graded Thermal Barrier Coatings (FG-TBC) increases the performance of high temperature components in gasoline engines by decreasing the thermal conductivity and increasing the unburned charge oxidation in the flame quenching area with the increase in temperature near the entrance of the crevice volume between the piston and the liner during the compression and the early part of the expansion strokes.

In this study, a 3-D finite element steady state thermal and structural analysis are carried out on both uncoated and functionally graded NiCrAlY/YSZ/Al₂O₃ coated gasoline engine piston using a commercial code, namely ANSYS. The effects of coating on the thermo mechanical behaviours of the piston are investigated. It has been shown that the maximum surface temperature of the ceramic coated piston is improved approximately by 7% for the Al-Si alloy. The application of TBC enhances the Von Mises stress withstanding capacity approximately by 15% than the uncoated piston due to maximum temperature difference and difference in thermal expansion coefficients within the ceramic layers.