Presentation Slides

Abstract:

The noise produced by engine cooling fans is a significant concern for manufacturers. We know that where and how we test these fans can influence the noise they generate. To explore this, we used PowerFLOW software with VLES formulation to examine an industrial engine cooling fan, for which we had experimental data.
When the fan blows freely in a semi-anechoic room, the airflow over the blades separates significantly. As the blade encounters a blockage, like a honeycomb structure, it experiences a distinct increase in load. This creates a highly tonal noise, with a clear peak at the blade passing frequency.
Testing the same fan in a free field environment revealed differences in the noise levels, especially in higher harmonics of the blade passing frequency. This difference is due to flow recirculations in the anechoic room.
When the fan operates at maximum efficiency, the primary noise generation mechanism is a back-flow vortex caused by the pressure difference across the fan interacting with the blades.

About the Speaker:

Francesco Bellelli is a PhD student in Computational Aeroacoustics at Politecnico di Torino. He earned his MSc Degree in Politecnico di Torino in July 2022 and started his PhD in November 2022. Francesco's primary research focus is the numerical assessment of the installation effects on the noise sources of industrial engine cooling fans to design quieter and more efficient fans.

@FB 
PhD Student, Politecnico di Torino

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