Effect of Mesh Size in Numerical Simulation of Turbine Housing in Turbocharger

Numerical method is popular in analyzing turbine housing in turbocharger with an early and rapid risk assessment. However, complex casting and extreme thermal loading from exhaust gas temperature and flow variation under engine duty cycle lead to big thermal stress and this makes material serviced in the plastic zone. Previous numerical simulations show that a mesh size is insensitive to the elastic finite element analysis (FEA), but might not be proper for elastic-plastic FEA, even that other boundary conditions keep same, which indicating simulation results are changeable with mesh size and a simple numerical mesh size convergence might not be enough to guarantee accurate numerical results as well. Therefore, several different mesh sizes are used in elastic-plastic analysis of turbine housing to investigate the influence on numerical results. Based on the numerical results and their comparison, we conclude that theoretical results exist under smaller finite element size but it is impractical to reach under elastic-plastics analysis in engineering application because industrial resource is not enough to support. The reasonable mesh size is recommended to consider both accuracy of simulation results and industrial resource. The fatigue life model and Goodman diagram should be calibrated as well based on this mesh size to evaluate turbine housing design risk.