Investigation and Recommendation of Exhaust Manifold Damage through Conjugate Heat Transfer Anaylsis

The rapid advances in computer and simulation technology make it possible to model complex geometrical shapes, material behaviour and thermal stresses, and to analyze the associated deformations and stresses under simulated operational conditions close to the real situation. The efficiency of the interdisciplinary metaphysics-analyses and the quality of their results are however highly dependent on the possibility to access the knowledge and expertise of company specialists in finite volume applications, materials sciences and fluid dynamics. A typical example of the numerical investigation of the thermo mechanical stresses in the exhaust manifold of an IC engine. In a first phase, CFD analyses for flange and manifold pipe assembly with test conditions with guesses operating boundaries were performed for this exhaust manifold aiming to determine sensible specific temperature and pressure distributions. The fluid flow and the heat transfer through the exhaust manifold were computed correspondingly by CFD analyses including the conjugate heat transfer. The temperature distributions of the solid part of the CFD mesh were neglected. Second phase of the modelling compares the existing model with the proposed model for test bed conditions for the same design model with similar approach. They were analyzed subsequently using the CFX V12 model of this component, consisting of 190000 elements, to quantify related temperature distribution and thermally induced stresses, in a two-way-coupling approach and considering nonlinear material behavior. The interpolation of the temperature data was done automatically in CFX solver. Selected details and results of the overall investigation are presented and discussed within the framework of this paper.