Reduction of Aero-Acoustics Tonal Noise for a Tractor Cooling Fan

Currently, noise pollution has become one of the major environmental concerns. To address this, new noise standards and regulations are being introduced and mandate the tractor OEM’s (Original Equipment Manufacturer) to meet the defined noise levels. Fan noise from the cooling fan is one of the key contributors to the overall vehicle noise. Hence, the reduction of fan noise at the source is a very important and critical task. Even though fan noise is broadband in nature its aerodynamic noise sources are most dominant at the higher harmonics of the blade pass frequency (BPF). The aerodynamic noise of a fan can be varied by changing the fan geometry viz., blade profile, fan width and diameter, number of blades, and ring on its periphery. A cooling fan is an important component of the cooling system which ensures adequate airflow for radiator cooling and avoids engine overheating with uniform heat dissipation. The important parameters that need to be considered while designing a cooling fan are noise level, airflow, and power consumption. A good fan design should provide a lower noise level while maintaining adequate airflow for the engine. The various fan designs are numerically simulated using experimentally validated CFD (Computational Fluid Dynamics) and CAA (Computational Aero Acoustics) techniques with appropriate boundary conditions to predict the airflow and noise level, respectively. With the aid of simulation, an improved 7-blade fan was developed with new blade profile and a ring on its periphery. The optimum blade profile ensured increased airflow for engine cooling and the ring on its periphery avoids turbulence resulting in lower noise. This project will also be considered for further validation plans on real-time vehicle applications to realize the objective of design as future scope of work.