Numerical and Experimental Studies of a Turbocharger Centrifugal Compressor for Combustion Engine Boost

Abstract

Increasing efficiency and extending the stable operating range of a turbocharger centrifugal compressor for combustion engine boost is one way to improve engines economical operation indices. In order to increase the centrifugal compressor’s efficiency, this work involves the numerical studies of the flow structure in the most widespread types of vaned diffusers: one-row, two-row, three-row, splitter and wedge diffuser. To confirm the adequacy of the numerical modeling results, the authors verified the design model and formulated recommendations on its settings to ensure the best correspondence between calculation results and experimental data. To extend the stable operating range of the centrifugal compressor, the authors performed numerical and experimental studies of casing treatments - ported shrouds and ring grooves in the shroud. The research findings demonstrated the high efficiency of the ported shroud, which allows the extension of the stable operating range by 4.5%. The authors carried out experimental studies of the influence of the centrifugal compressor diffuser type – vaned and vaneless – on the ported shroud efficiency. The displacement of the surge line is achieved in the configuration with the vaneless diffuser due to the implementation of the ported shroud is 10-12% greater than in the configuration with the vaned diffuser. The article is also of interest for designers of centrifugal compressors of turboshaft and small-sized turbojet engines, for which the problem of increasing the efficiency and extending the stable operating range of the compressor is also actual.