CFD Analysis of Flow Behavior and Thermal Performance in Single and Multi-Inlet EGR Coolers

Abstract

In heavy-duty vehicles, Exhaust Gas Recirculation (EGR) coolers have been used since 2002 to reduce NOx emissions by recirculating exhaust gases. EGR systems increase fuel efficiency and achieve more thorough combustion, while the EGR cooler, which cools the exhaust gases, is crucial to protect the engine by lowering the combustion temperature. This research evaluates the flow behavior and thermal characteristics of EGR coolers using the k-omega turbulence model. The study compares the effectiveness of two designs of EGR coolers: the single coolant inlet type and the four-inlet type configuration. The CAD design of the EGR cooler is developed in Creo design software, and CFD simulations are conducted using the ANSYS CFX simulation package. The results show that the incorporation of additional coolant inlet tubes improves the EGR cooler's performance. The four-inlet design exhibits higher effectiveness compared to the single-inlet design at every operating temperature. The effectiveness is maximum at an operating temperature of 691K, and the four-inlet design shows 0.02 higher effectiveness than the single-inlet design at an operating temperature of 1058K. The conventional design of the EGR cooler with a single coolant inlet can be substituted with the new proposed design of the EGR cooler with four coolant inlets. The new proposed design of the EGR cooler has higher effectiveness and would enable the reduction of NOx emissions and improve engine efficiency.