Analyzing the Impact of Cracks on Exhaust Manifold Performance: A Computational Fluid Dynamics Study

Abstract

The exhaust manifold system plays a vital role in the internal combustion engine of a vehicle, functioning in conditions of high temperature and pressure. The objective of this analysis is to assess how the presence of the crack influences the pressure drop across the exhaust manifold. Understanding pressure drop is essential in determining the efficiency of the exhaust system and its effect on engine performance. Furthermore, we investigate how a crack in the exhaust manifold affects the flow patterns of exhaust gases, including changes in velocity, pressure distribution, and turbulence within the manifold; The results of the analysis show that the crack has various implications for both the performance and structural integrity of the manifold. It causes an increase in pressure drop across the manifold, resulting in reduced engine efficiency. Additionally, the crack induces turbulence or vortex formation in the exhaust gases, further impacting the system's performance, and finally, the impact of the presence of a crack typically results in an elevated coefficient of friction.

On the Accuracy of Turbulence Model Simulations of the Exhaust Manifold

“…In Figure 3, mesh inflation is employed around the exhaust gas to ensure a y+ value of less than 1 throughout all simulations. An inflation mode with 5 layers is also used, adding extra layers of mesh cells near the solid boundaries where significant flow gradients are present (e.g., Ouyoussef et al [35]). These layers are gradually refined toward the wall to provide better resolution of the boundary layer and to capture the flow phenomena in that region.…”