Computational fluid dynamic and fatigue analysis of turbocharger turbine wheel

Turbochargers are essential for improving engine efficiency by compressing air and delivering it to the engine at higher pressure, thereby increasing power output. The turbine wheel in a turbocharger operates under severe mechanical and thermal stresses, making it highly susceptible to fatigue failure, which can occur even under conditions below the rated operating load. To ensure long-term reliability, detailed analysis of the turbine’s fatigue life is essential. This study combines computational fluid dynamics with fatigue analysis to predict the performance and lifespan of a turbocharger's turbine wheel, with a focus on Inconel alloys known for their durability in extreme conditions. A numerical mesh analysis, employing 1,165,610 nodes, was conducted to achieve convergence for both temperature and stress evaluations, leading to the selection of a 2 mm mesh size. Pressure contours at the turbine-fluid interface revealed a pressure range between 1.09 and 1.05 bar, with most of the turbine maintaining a temperature of 700°C, indicating an isothermal condition. Fatigue life predictions using the Geber model, effective for ductile materials, highlighted localized reductions in life expectancy around the blade tip, while most components maintained a factor of safety between 3 and 4, with a maximum of 15. Considering creep effects at 700°C, the turbine's safe operational life was estimated at 591 days. These findings were used to recommend critical design modifications to enhance the turbine’s durability and performance.