CFD INVESTIGATION OF IMPELLER DIFFUSER INTERACTION EFFECTS ON RADIAL COMPRESSOR STAGE
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
The effects of impeller-diffuser interaction are investigated through numerically simulating the modified wedge vane profiles. Steady and time-accurate, 3D- viscous RANSsolver is used to perform flow field computations.
The original design is modified to obtain better aerodynamic performance. Five morechanges are made to the leading edge profile of the new design, in order to assess different degrees of unsteadiness. These changes show that their contribution on stageefficiency is rather minor, while they have a huge reduction on blade loadings. Moreover, it is shown that the shorter radial distance of vaneless space does not necessarilymean an increased loading thanks to the eliminating in-phase fluctuations on pressureand suction sides.
It is found that the impeller reacts to the upstream static pressure disturbance, whichis caused by the applied geometry change and its resultant flow field in the wedge diffuser, but not to the radial location of a certain profile. In addition, the results indicatethat the wedge diffuser aerodynamic performance is driven by time-averaged flow fieldbehaviour.
Place, publisher, year, edition, pages
2014. , 83 p.
CFD, impeller-diffuser interaction, radial compressor, centrifugal compressor, vaneless space
Mechanical Engineering Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-157534OAI: oai:DiVA.org:kth-157534DiVA: diva2:770579
Master of Science - Turbomachinery Aeromechanic University Training
2014-09-23, Royal Institute of Technology, KTH, Brinellvägen 68, Stockholm, 15:00 (English)