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Article

Numerical Flow Analysis of a Centrifugal Compressor with Ported and without Ported Shroud

Authors: Kumar, J.K., Semlitsch, B., Mihaescu, M, Fuchs, L.F., Gutmark, E., Gancedo, GM
Document Type: Conference
Pubstate: Published
Journal: SAE 2014 World Congress & Exhibition
Volume: 14PFL-0797   8
Year: 2014

Abstract

Turbochargers are commonly used in automotive Diesel engines to increase the internal combustion engine performance. In use, a most wide operation range for the turbocharger is desired. The operation range of a turbocharger centrifugal compressor is limited by the choke condition and the surge phenomenon. The ported shroud technology is used to improve the operation range of the compressor, which permits flow disturbances that block the blade passage to escape and recirculate to the compressor inlet. The effectively of this technology over a wide range operation conditions is investigated. A numerical study of the flow in a centrifugal compressor of an automotive turbocharger has been performed using the Large Eddy Simulation approach and the wheel rotation is handled by the sliding mesh technique. In this analysis, the full compressor geometry (360 deg) is taken into account. A comparative study has been carried out comparing the obtained numerical solutions with and without ported shroud for the design and near-surge operating conditions. The flow-field of the different cases is analyzed to explain the functionality of the ported shroud. It was found that the ported shroud reduces the flow disturbances in the blade passage for all operating conditions. However, the compressor efficiency for the off-design operation condition was found to be higher without using a ported shroud. The computational results are validated with experimental obtained results for the performance parameters.