Radiator inlet grille modeling for motorsport applications
F. Cerbino (TU Delft - Aerospace Engineering)
A.H. van Zuijlen – Mentor (TU Delft - Aerodynamics)
A. Bongiovanni – Mentor
A. Sciacchitano – Graduation committee member (TU Delft - Aerodynamics)
S.J. Hulshoff – Graduation committee member (TU Delft - Aerodynamics)
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Abstract
In high-performance motorsport, thermal management systems are critical for maintaining optimal vehicle operating conditions. Protective grilles installed ahead of radiators and heat exchangers shield these components from track debris but introduce static pressure losses due to aerodynamic blockage. Accurate and cost-effective modeling of grille effects is essential to ensure adequate cooling while maximizing aerodynamic performance.
This research project aimed to identify the main pressure drop drivers and develop an accurate, cost-effective numerical model for simulating arbitrary grille geometries. The impact of grille location and geometrical construction on radiator performance was analyzed to optimize cooling efficiency and aerodynamic performance. The investigation employed Computational Fluid Dynamics (CFD) RANS simulations using Ansys Fluent. Although multiple validation attempts were conducted using a radiator test bench, the experimental results showed unsatisfactory reproducibility and coherence.
The investigation identified the hexagonal mesh pattern with circular wire as the optimal grille configuration, delivering the lowest static pressure losses while maintaining equivalent debris protection. Pressure loss proved slightly more sensitive to wire thickness changes than to opening size variations. In both cases, the optimal configuration exists at the structural and functional limits: wire should be as thin as structurally viable, and openings as large as possible while maintaining protective capability.
Although pressure loss across the grille and radiator was independent of their separation distance, the radiator demonstrated increased aerodynamic efficiency when distance was minimized, making this the preferable setup. The research also explored using protective grilles to deflect and align airflow with the radiator inlet face. However, the complexity of achieving optimized grille design, combined with additional custom manufacturing costs, rendered this concept impractical.
Data from numerical tests on various grille configurations formed the foundation for developing a mathematical model capable of predicting pressure losses for arbitrary grilles at incoming flow speeds ranging from 6 to 22 m/s. This formulation was subsequently used to represent the grille as a porous medium. Numerical validation demonstrated that the modeled grille in series with a radiator exhibited total pressure loss only 0.5% higher than the geometrically modeled configuration, confirming the approach's robustness and accuracy.
This research advanced understanding of the aerodynamic impact of motorsport protective grilles, clarifying how key geometrical parameters and positioning relative to the radiator affect pressure losses. The developed grille modeling provides a robust and accurate method for simulating aerodynamic impact, enabling reduced safety margins in cooling system design. This work paves the way for further iterations and validation tests, ultimately supporting implementation in full-scale car simulations and contributing to more efficient thermal management solutions in high-performance motorsport applications.