Thermal Stress Analysis for D5S Cast Iron Exhaust Manifold of a Turbo-Charged Gasoline Engine Based on FSI Method and Temperature-Detection

This research work is directed toward determining the thermal stresses in a Ni-Resist cast iron commercial exhaust manifold of a turbo-charged gasoline engine. At first, based on a fluid-structure interaction (FSI) method, the steady state temperature distributions in the exhaust gas as well as in the exhaust manifold set are determined, using a CFD model. The thermal B.C.’s previously estimated by conducting a motor temperature detection test. Next, to conduct a thermal stress analysis, a full FEM model for the manifold set has been generated in the Abaqus software, and the mechanical B.C.’s are imposed in that. Also, the temperature distribution resulted from the thermal analysis imputed to the nonlinear FEM model as a predefined temperature field. Also, the range of temperature variations in the manifold is defined for the software material property module, so that Abaqus computes the material properties and stresses in each point according to the local temperature. Finally, executing the FEM model, the thermal stress distributions are computed. The numerical results show that the thermal stresses have the most critical values at the confluence region of the manifold, and maximum shear stresses occur around the bolted joints.