The appropriate choice of an automotive turbocharger compressor for an internal combustion engine is based on the compressor performance, which is commonly specified on a compressor map for different operating conditions. A wide operating range for the compressor covering all possible engine working conditions is desired. However, the application range of the compressor is limited. Different compressor designs are used to fit specific engine requirements. Naturally, these will have rather different characteristic compressor maps. The aim of the present investigation is to explain the differences in the compressor maps by analyzing the compressible flow-fields in two compressor designs from the same manufacturer, intended for a light-duty vehicle (passenger car). The flow-fields are assessed by steady-state Reynolds Averaged Navier-Stokes (RANS) simulations for several operating conditions. Similar flow features are observed near optimal efficiency operating conditions when the flow-field parameters are scaled properly. This study exposes the reason for the different measured operating ranges of the two compressors when ran at the same speed lines.
QC 20150805