Assessment of a One Dimensional Loss Model For The Compressor of a Turbocharger

Sammanfattning: This report sets out to implement and asses a one-dimensional loss model for centrifugal compressors. The loss model which has been evaluated is the model by Oh et al. (1997) [1]. The implementation was completed using iterative methods implemented in Matlab. It was shown that the performance prediction using the Oh et al method produced usable estimates in the higher rotational speed region used in this work, at design conditions. The pressure ratio estimates had a difference compared to the measured reference data of 5-10% while the isentropic efficiency had slightly higher differences. Furthermore, it was shown that the best estimates of the pressure ratio came from the lowest rotational speeds, and successively flattened out from the expected curvature as the speed increased. The isentropic efficiency did not have the same property, giving the best consistent estimate at a higher rotational speed of 143 kRPM. The conclusion which was drawn from this work was that the model by Oh et al. is a useful model for prediction of performance at design points in the lower RPM region, while requiring complementary calculations at off-design conditions at high RPM. It was also pointed out that there are several areas that require further work within performance prediction to make it more implementation-friendly.