Thermo-mechanical high-cycle fatigue analysis of exhaust manifold of turbocharged engine with two-way coupling FSI

NNowadays, car manufactures in order to increasing torque and power with consider to fuel consumption, have swept to production of turbocharged engines. With consider to exhaust gas-temperature rises in boosted engines, recognition of critical locations of exhaust manifold in the worse condition of engine (full load and maximum speed), to prevent fracture of exhaust manifold is very important. In this research thermomechanical analysis, fatigue and life-span estimation in the most critical case of engine performance with using two-way coupling of fluid and solid has been carried out. In two-way coupling in every time step first, flow analysis of manifold is carried out in FLUENT software, then, temperature, convective heat transfer coefficient and pressure of fluid are mapped to inner shell of exhaust manifold. In solid preload of bolts, elastic foundation based for effect of cylinder head and turbocharger were considered and thermomechanical analysis was carried out with ANSYS software. Then with computing strain and changing geometry, new mesh for analysis in next time step was entered into FLUENT software and this cycle with consider to time step until end of cycle was carried out. Results of thermal simulation in fluid and solid was validated with experimental data. Finally, temperature, heat transfer coefficient, solid temperature, strain, normal stresses, Von Misses stress and dynamic stress plot and life-span of exhaust manifold have been estimated.