Energy Exchange and Secondary Losses Prediction in High Speed Axial and Radial Compressors

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In this paper an extension of our secondary flow calculation method is presented in order to estimate the energy exchange and the secondary losses in axial and radial compressors. Although it is well known today that end-wall shear layers play a major role in the performance of the compressors, there are only few secondary flow methods able to predict realistically the behaviour of real machines. For this purpose a new theory was developed which extends Mellor’s basic principles and uses our previous work, including the complete form of meridional vorticity transport equation. A coherent model for the real work exchange between the fluid and the machine has been developed, as well as for the distribution of secondary losses, not only at the compressor’s exit but also at every station through the machine. An expression for the added work due to the secondary field is also given. Finally the influence of secondary losses in the overall efficiency is well estimated. This work has been successfully applied to a highly loaded compressor cascade, as well as to a transonic axial compressor and to a radial one-stage one. Comparison between theoretical and experimental results is also presented.