Time filter

Source Type

Schneider C.M.,Institute of Aircraft Propulsion Systems ILA | Schrack D.,Institute of Aircraft Propulsion Systems ILA | Kuerner M.,Institute of Aircraft Propulsion Systems ILA | Rose M.G.,Institute of Aircraft Propulsion Systems ILA | And 3 more authors.
Proceedings of the ASME Turbo Expo | Year: 2013

This paper addresses the unsteady formation of secondary flow structures inside a turbine rotor passage. The first stage of a two-stage low pressure turbine is investigated at a Reynolds Number of 75 000. The design represents the third and the fourth stages of an engine representative low pressure turbine. The flow field inside the rotor passage is discussed in the relative frame of reference using the streamwise vorticity. A multi-stage URANS prediction provides the time-resolved data set required. It is supported by steady and unsteady area traverse data acquired with five-hole probes and dual-film probes at rotor inlet and exit. The unsteady analysis reveals a non-classical secondary flow field inside the rotor passage of this turbine. The secondary flow field is dominated by flow structures related to the upstream nozzle guide vane. The interaction processes at hub and casing appear to be mirror images and have characteristic forms in time and space. Distinct loss zones are identified which are associated with vane-rotor interaction processes. The distribution of the measured isentropic stage efficiency at rotor exit is shown which is reduced significantly by the secondary flow structures discussed. Their impacts on the steady as well as on the unsteady angle characteristics at rotor exit are presented to address the influences on the inlet conditions of the downstream nozzle guide vane. Copyright © 2013 by ASME.


Schneider C.M.,Institute of Aircraft Propulsion Systems ILA | Schrack D.,Institute of Aircraft Propulsion Systems ILA | Kuerner M.,Institute of Aircraft Propulsion Systems ILA | Rose M.G.,Institute of Aircraft Propulsion Systems ILA | And 3 more authors.
Journal of Turbomachinery | Year: 2014

This paper addresses the unsteady formation of secondary flow structures inside a turbine rotor passage. The first stage of a two-stage, low-pressure turbine is investigated at a Reynolds Number of 75,000. The design represents the third and the fourth stages of an engine-representative, low-pressure turbine. The flow field inside the rotor passage is discussed in the relative frame of reference using the streamwise vorticity. A multistage unsteady Reynolds-averaged Navier-Stokes (URANS) prediction provides the timeresolved data set required. It is supported by steady and unsteady area traverse data acquired with five-hole probes and dual-film probes at rotor inlet and exit. The unsteady analysis reveals a nonclassical secondary flow field inside the rotor passage of this turbine. The secondary flow field is dominated by flow structures related to the upstream nozzle guide vane. The interaction processes at hub and casing appear to be mirror images and have characteristic forms in time and space. Distinct loss zones are identified, which are associated with vane-rotor interaction processes. The distribution of the measured isentropic stage efficiency at rotor exit is shown, which is reduced significantly by the secondary flow structures discussed. Their impacts on the steady as well as on the unsteady angle characteristics at rotor exit are presented to address the influences on the inlet conditions of the downstream nozzle guide vane. It is concluded that URANS should improve the optimization of rotor geometry and rotor loss can be controlled, to a degree, by nozzle guide vane (NGV) design. © 2014 by ASME.

Loading Institute of Aircraft Propulsion Systems ILA collaborators
Loading Institute of Aircraft Propulsion Systems ILA collaborators