Transient compressible simulation of a high-speed radial compressor using the CATHARE system code

Abstract

The French Alternative Energies and Atomic Energy Commission (CEA) works on Brayton cycles modeling and design for energy conversion systems of gas cooled reactors. To provide a solution for the pre-design of turbomachinery and the simulation of transient compressible flows, the thermal-hydraulic simulation section has worked on a onedimensional rotodynamic pump model. This is a predictive transient two-phase flow model which considers a mean streamline adopted by the fluid on each element of the machine (fixed and rotating parts). Originally dedicated to pumps, the method is applied here to the prediction of the performance of the Low-Speed Centrifugal Compressor from NASA. Direct application of the 1-D pump model on the compressor leads to a relative error to the experimental data of 2,2% on the pressure ratio and 7,0% on the isentropic efficiency at the nominal point, with correct overall trends. A development of an improved mean flow path is carried out, providing a base to qualify the model on other compressors.