Fan and fan-shroud design is critical for underhood air flow management. The objective of this work is to demonstrate a method to optimize fan-shroud shape in order to maximize cooling air mass flow rates through the heat exchangers using the Adjoint Solver in STAR-CCM+®. Such techniques using Computational Fluid Dynamics (CFD) analysis enable the automotive/transport industry to reduce the number of costly experiments that they perform. This work presents the use of CFD as a simulation tool to investigate and assess the various factors that can affect the vehicle thermal performance.
In heavy-duty trucks, the cooling package includes heat exchangers, fan-shroud, and fan. In this work, the STAR-CCM+® solver was selected and a java macro built to run the primal flow and the Adjoint solutions sequentially in an automated fashion. In this analysis, the primal flow provides flow information (e.g. velocity, temperature and pressure) and the Adjoint solver provides surface morphing details w.r.t. max or min of the specified objective function. In the present work, the fan-shroud surface morphing was performed based on the maximum air mass flow rate through the heat exchanger outlet w.r.t. the spatial positions of the fan-shroud surface. An overall 1.4% increase in cooling air mass flow was observed in the heat exchanger with the optimized/morphed fan-shroud surface. The identified main optimized locations were mainly at the sharp edges of the original manufactured fan-shroud. Further evaluation is underway to maximize the cooling air mass flow benefit.