Fatigue analysis of stainless steel exhaust manifold using fluid-solid coupling method

The fluid-solid coupling method simulates and analyzes the dynamic effects of fluid flow on solid structure by establishing the interaction relationship between fluid domain and solid domain. In the fatigue analysis of stainless steel exhaust manifold, this method can capture the thermal stress effect of high-temperature and high-pressure gas flow in the exhaust manifold on the manifold structure, as well as the fatigue damage caused by it.
Application steps of fluid-solid coupling method
Model establishment: According to the actual structure of the stainless steel exhaust manifold, its three-dimensional geometric model is established. At the same time, the fluid domain and solid domain are defined and the grid is divided. The fluid domain usually includes the gas flow area inside the exhaust manifold, while the solid domain includes the manifold itself and its connecting parts.
Fluid dynamics analysis: The gas flow in the exhaust manifold is simulated and analyzed using fluid dynamics software (such as CFD software). The convection heat transfer coefficient and temperature distribution of the inner wall of the exhaust manifold are obtained by calculation as the input conditions for subsequent solid mechanics analysis.
Solid mechanics analysis: The thermal boundary conditions obtained from the fluid dynamics analysis are applied to the solid structure analysis model, and the exhaust manifold is subjected to thermal stress analysis using solid mechanics software (such as Abaqus, ANSYS, etc.). The temperature field, stress field and strain field of the exhaust manifold are calculated to evaluate its fatigue performance.
Fatigue life evaluation: Based on the results obtained from solid mechanics analysis and combined with the fatigue properties of the material (such as S-N curve, fatigue limit, etc.), the fatigue life of the stainless steel exhaust manifold is evaluated. The fatigue life and fatigue damage degree of the manifold are calculated to provide a basis for a good design.