Investigations On The Dynamic Coefficients Of Impeller Eye Labyrinth Seals.

Abstract

For many application fields of turbocompressors the rotor stability has become the most important part of the rotordynamic analysis. A comprehensive knowledge of these seal forces is mandatory to ensure an adequate overall design of the compressor as early as the quotation phase. While in earlier times the focus was on the balance drum contribution as the major source of excitation, it has in the meantime become evident that the effects from the impeller eye-seals also have to be considered as a further destabilizing contribution. However, up to now the task of measurement of impeller-eye-seal dynamic coefficients has remained a major challenge. This paper presents a new approach for generation of high-quality data on a unique full-scale high-pressure test rig, in which specific attention is paid to impeller-eye seals. The applied strategy combines results from the test rig obtained from different methods with findings from computational fluid dynamic (CFD) investigations. The publication of dimensional data offers further use of these results within the turbomachinery community.