Computational fluid dynamics simulation of heat transfer performance of exhaust gas re-circulation coolers for heavy-duty diesel engines

Abstract

In order to estimate the performance of exhaust gas re-circulation coolers two factors were considered: the cooling efficiency and pressure drop. For that, three models of exhaust gas re-circulation coolers intended to heavy-duty Diesel engines were chosen and studied by numerical simulations. The CFD software FLUENT was used to solve the governing equations. Temperature dependant physical properties of the recycled exhaust gas were incorporated via the "User Defined Functions" feature of FLUENT. The inlet temperature of the exhaust gas is set to 523.15 K and the inlet mass-flow rate changes from 0.07 up to 0.2 kg/s. The computed performance results were compared to existing experimental measurements. The comparison of the computed results for the three models allowed to distinguish the exhaust gas re-circulation cooler model consisting of 19 tubes with helical baffles as having the best performance in terms of cooling efficiency and pressure drop.