Convegni ATI - Accesso riservato soci CTI

Autore: E. Canepa, M. Caruggi, A. Cattanei, M. Ubaldi, P. Zunino

Collana: CA - 59 - Genova 2004

Note:
The flow within the impeller of a centrifugal turbomachine model operating at very low flow rate has been experimentally investigated by means of a two components laser Doppler anemometer. The radial and circumferential velocity components have been measured on five cross-sectional cylindrical surfaces within the impeller and on the midspan blade-to-blade plane. The periodic flow component has been separated from turbulent fluctuations by means of the ensemble-average technique. The results show the impeller flow structure and the main features of the flow entering the diffuser. A comparison is done with a similar study previously carried out on the same machine at design and moderately reduced flow rate. At these two working points the flow on the blade suction side and by the recirculating flow caused by the counter rotating vortex which forms at the shroud and pushes the flow towards the hub. Comparing to less severe working conditions, the flow shows a strong disuniformity in the axial direction rather than in the tangential one.