Dynamics of the inlet recirculation region in a turbocharger compressor

• A numerical study is presented where Large Eddy Simulation (LES) calculations are used in an effort to characterise flow-acoustic interaction in a turbocharger compressor operating at near surge conditions. Under such off-design operation, an inlet recirculation zone develops upstream of the compressor following the compressor inlet duct. Previous studies have shown that the development of reversed flow can impact the sound power level of the blade passing frequency (BPF) tones and broadban whoosh noise. In this study local mesh independence studies are performed to capture the vortical structures in the recirculation region, which are often not properly resolved. Computational grid refinements in the fluid domain are applied based on extimated of the local Taylor microscale in the flow. Moreover, the grid resolution is enhanced in the region where domainant acoustic sources are to be expected according to Proadman noise source model. The temperature field and the velocity components with correponding standard deviations are quantified and validated against avaliable experimental data. The analysis of the LES data allows quantifying the dynamics of the developed recirculation zone in space and time and enables a detailed assessment on the impact it has on the incoming flow, explaining its contribution to the flow-induced noise mechanisms in a centrifugal compressor.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Strömningsmekanik och akustik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Fluid Mechanics and Acoustics (hsv//eng)

Nyckelord

Teknisk mekanik

Engineering Mechanics

Publikations- och innehållstyp

vet (ämneskategori)

ovr (ämneskategori)