Numerical simulations of flow induced noise from a dual rotor cooling fan used in electronic cooling systems

Abstract

Hard Disk Drive (HDD) system enclosures in a data center require effective cooling systems to avoid HDD overheating. These systems often rely on air cooling because of their cost effciency and maintainability. Air cooling systems typically consist of an array of axial fans which push or pull the air through the system. These fans emit high level tonal noise particularly at high tip speed ratios. High-capacity HDDs, on the other hand, are sensitive to high acoustic noise, which consequently increases the risk of read/write error and deteriorates drive performance. Therefore, cooling fan noise adversely affects the function of the HDD enclosure systems which emphasizes the need to understand the noise sources and develop methods to mitigate HDD noise exposure.

Numerical analysis of acoustic noise from an electronic cooling fan at flow disturbed by an external obstacle

“…These rotors and stator are covered with a cylindrical shroud. Previously validated open fan configuration [12] has been used as the reference case. Here, the front rotor rotates at 12960 RPM, and the rear rotor rotates at 13740 RPM.…”

“…The flow field was simulated using LES following the approach described in [12]. The characteristic chord length is about 3 cm.…”

“…The present work is an extension of the work presented at the INTER-NOISE 2021 conference [12]. Previously, authors validated the LES and Ffowcs-Williams and Hawkings (FW-H) based noise prediction model using a fan that is typically used in a large scale data center HDD enclosure system.…”

“…Previously, authors validated the LES and Ffowcs-Williams and Hawkings (FW-H) based noise prediction model using a fan that is typically used in a large scale data center HDD enclosure system. Theoretical background and the methodology of validation can be found in [12]. In this paper, the authors focus on evaluating fan noise effects due to simplified grille structures close to the fan's inlet.…”

On the Fast Prediction of the Aerodynamic Performance of Electronics Cooling Fans Considering the Effect of Tip Clearance

“…Recently, more advanced computational fluid dynamics (CFD) methods have been proposed as alternatives to the LF approach with good results in electronics cooling applications. The large eddy simulation (LES) was combined with the Ffowcs Williams and Hawkings (FW-H) approach to calculate the aerodynamic and aeroacoustic performance of a counterrotating cooling fan, with excellent agreement with experimental results [10], [11]. Steady/unsteady Reynolds-averaged Navier-Stokes (U/RANS) CFD, combined with the moving reference frame (MRF), have also been found to be reliable for electronics cooling applications [12], [13].…”