DEVELOPMENT OF TRANSONIC CENTRIFUGAL COMPRESSOR WITH AN INDUCER CASING BLEED SYSTEM

Abstract

A transonic centrifugal compressor (MU2>1.5) is developed with an inducer bleed system. The configuration is comprised of an axial intake, an impeller and a vaned diffuser that are suited for high efficiency applications. Rig test data is based on performance rakes, wall static pressure taps distributed along static parts, dynamic pressure measurements at critical locations, etc. acquired at various rotational speeds. Impeller and diffuser performance are deduced and the inlet recirculation is observed upstream of the impeller from the test. Numerical method is validated against test data and different turbulence models are also tried. Inducer bleed system widens the flow range and improves stall margin, efficiency (by more than 5%) at low rotational speeds by correcting the incidence at the impeller inlet. On the other hand at design speed operations, choke margin is enhanced by the drawing air from the inducer port into the impeller. The benefit of the inducer bleed system is clearly shown in the results from the stall margin, efficiency and flow range standpoints. Impeller stall is entirely averted and vaned diffuser stall is observed in all occasions, in terms of choking, vaned diffuser is responsible for the entire range of operation. © 2024 Elsevier B.V., All rights reserved.