Loss Analysis Of Centrifugal Compressor Volutes Based On A Second-Law Analysis Method

Authors

Daniel Wolbert  - University of Applied Sciences Trier, Germany
Sven Koenig - University of Applied Sciences Trier, Germany
Michael Wannek - Siemens Energy, Germany
Joerg Hartmann - Siemens Energy, Germany

Abstract

Loss modeling of centrifugal compressor volutes is generally based on the use of physical approaches in combination with empirical data, providing an abstract description of the loss development of the highly complex, three-dimensional volute flow. Another evaluation technique for the losses is provided by the so-called second-law analysis (SLA), in which entropy productions are used to analyze the loss mechanisms as well as to quantify the local loss distribution within the volute. The present work is based on the application of that method, in which numerical simulations are used to obtain further knowledge in the field of volutes of centrifugal compressors. Steady-state flow simulations of different volute types have been carried out using the industry-standard SST turbulence model, whose numerical methodology has been validated against experimental data for the standard case of an outward-wound volute with a circular cross-section. Based on the numerical results, a physical relation between the entropy production and the total pressure losses inside the volute is presented, allowing the attribution of the loss characteristics to the local entropy productions in specific flow regions of the volute.