Thermal Examination of a Simplified Exhaust Tube-Heatshield Model

Abstract

Exhaust system and its surrounding is a thermally highly critical part of a vehicle: during forced operation, hottest elements can reach 600 °C. The thermal conditions turn to even more critical if the forced flow leaves off – e.g. when the car stops at a highway parking place. In such a case not only the cooling effect of cross-flow disappears, but the natural convection starts to bring heat toward nearby elements – resulting potential overheating of concerned parts. A measurement setup for modelling such case was built, and different parameters were examined, which have influence on the heating of aluminium heatshield above the exhaust tube. Measurements were complemented by CFD simulations and flow visualization technique aiming the better understanding of evolving thermal and flow conditions.