Theoretical and experimental investigations regarding the flow in reversing channels of turbomachines

A suitable approach for the enhancement of the performance and efficiency of a turbomachine is based on the improvement of the design of the individual components of the machine. A multistage radial-flow compressor is considered, taking into account the impeller, the diffuser, and a curved channel producing a change in the direction of the flow of 180 deg. A knowledge of the processes occurring during the change of the flow direction is of great importance for the evaluation of the operational characteristics of the entire machine. A computational procedure which describes this flow in detail is, therefore, very useful. For these reasons, the present investigation is concerned with a mathematical model of the flow through a curved channel. This model makes it possible to calculate with the aid of a computer the characteristics of the considered flow. Attention is given to the theoretical derivation of the computational procedure, the implementation of the procedure, a comparison of the obtained results with the exact solutions of the Navier-Stokes equations, experimental studies related to the reversal of the flow direction, and a comparison of computational and experimental results.