Assessment of the 3D Flow in a Centrifugal compressor using Steady-State and Unsteady Flow Solvers

2014-01-2856

10/13/2014

Event
SAE 2014 International Powertrain, Fuels & Lubricants Meeting
Authors Abstract
Content
Numerical analysis methods are used to investigate the flow in a ported-shroud centrifugal compressor under different operating conditions, i.e. several mass flow rates at two different speed lines. A production turbocharger compressor is considered, which is widely used in the heavy automotive sector. Flow solutions obtained under steady-state and transient flow assumptions are compared with available experimental data.
The steady-state Reynolds Averaged Navier-Stokes method is used to assess the overall time averaged flow and the global performance parameters. Additionally, the Large Eddy Simulation (LES) approach is employed to capture the transient flow features and the developed flow instabilities at low mass flow rates near the surge line.
The aim of this study is to provide new insights on the flow instability phenomena in the compressor flow near surge. Comparison of flow solutions obtained for near-optimal efficiency and near-surge conditions are carried out. The unsteady features of the flow field are quantified by means of Fourier transformation analysis, Proper Orthogonal Decomposition and Dynamic Mode Decomposition. For a near optimal efficiency set-up the frequency spectra are broad-banded with no distinct instabilities. Close to the surge line, the spectra show a distinct surge cycle frequency, which is due to flow pulsation in the compressor.
The modal flow decomposition elucidates a mode occurring at the surge frequency. The mode explains the oscillating pumping effect occurring during surge. The surface spectra contours reveal the shape of the pressure pulsation during surge and support that a pressure gradient occurs with the oscillating modes found with the modal decomposition.
Meta TagsDetails
DOI
https://doi.org/10.4271/2014-01-2856
Pages
13
Citation
Sundström, E., Semlitsch, B., and Mihaescu, M., "Assessment of the 3D Flow in a Centrifugal compressor using Steady-State and Unsteady Flow Solvers," SAE Technical Paper 2014-01-2856, 2014, https://doi.org/10.4271/2014-01-2856.
Additional Details
Publisher
Published
Oct 13, 2014
Product Code
2014-01-2856
Content Type
Technical Paper
Language
English