Optimization of Front End Cooling Module for Commercial Vehicle Using CFD Approach 2013-26-0044

Assessment of cooling performance in the design stage of vehicle allows a reduction in the number of needed prototypes and reduces the overall design cycle time. Frontend cooling and thermal management play an essential role in the early stages of commercial vehicle design. Sufficient airflow needs to be available for adequate cooling of the under-hood components. The amount of air mass flow depends on the under-hood geometry details, positioning and size of the grilles, fan operation and the positioning of the other components. Thermal performance depends on the selection of heat exchanger.

This paper describes the effects of several design actions on engine cooling performance of a commercial vehicle with the help of Computational Fluid Dynamics (CFD) simulation tool Fluent™. Front of vehicle design is captured in detailed FE model, considering front bumper, grille, cabin, cargo and surrounding under-hood and underbody components. Heat exchangers are model as porous medium and performance data are generated in 1-D Kuli™ software. This data was used as input for heat exchangers performance calculation in analysis. Temperature drop at intercooler and radiator outlets are predicted with amount of heat rejection. This analysis helps to predict the air flow pattern in under-hood and underbody regions. The CFD front-end cooling simulations are done for two vehicle conditions, maximum torque and maximum power. Hot and cold air recirculation zones are identified in under-hood compartment. Elimination of hot air recirculation over intercooler and radiator showed good improvement in cooling performance. The design actions involve the modifications of the front end geometry and implementation of different heat exchangers and fans.

The developed methodology is validated by correlation study with cooling test results in both the vehicle conditions of an existing vehicle. Overall CFD predictions agree well with the test results.