Coupled CFD–FE analysis for the exhaust manifold to reduce stress of a direct injection-diesel engine

Abstract

ABSTRACTThe present work deals with the investigation of the exhaust manifold of a four-cylinder diesel engine. Geometry creation and finite element method of the exhaust manifold was done using Computer Aided Design and CAE software. To simulate the thermal boundary coefficients of the exhaust manifold wall under steady-state loading conditions, the internal flow field structure was obtained using Computational Fluid Dynamics (CFD) software. The thermal boundary conditions were mapped to structural element surfaces of the exhaust manifold based on commercial finite element code ABAQUS. Thermal analysis was conducted to find out the high thermal stress areas. Design modifications were done on the high stress area and the process was repeated and stresses were reduced to meet the target. Numerical results and contour plots were reported on. The analysis of such a system is critical due to the complexity of meeting the structural and flow requirements. The use of coupled CFD and FEA simulation gives a better prediction of thermal stresses and flow behaviour in the exhaust manifold. The simulation captures the stress pattern and stress concentration at the failure location. The modification has reduced the stress level by 13% and eliminated the stress concentration.