This paper investigates the effects of compressibility and unsteadiness due to the relative blade row motion and their importance in the interaction between hub leakage (purge) and mainstream flows. First, the challenges associated with the blade redesign for low-speed testing are described. The effects of Mach number are then addressed by analyzing the experiments in the low-speed linear cascade equipped with the secondary airflow system and computations performed on the low- and high-speed blade profiles. These results indicate that the compressibility does not significantly affect the interaction between the leakage and mainstream flows despite a number of compromises made during the design of the low-speed blade. This was due to the fact that the leakage–mainstream interaction takes place upstream of the blade throat where the local Mach numbers are still relatively low. The analysis is then extended to the equivalent full-stage unsteady computations. The periodic unsteadiness resulting from the relative motion of the upstream vanes appreciably affected the way in which the leakage flow is injected and the rotor flow field in general. However, the time-average flow field was still found to be dominated by the rotor blade's potential field. For the present test arrangement, the unsteady effects were not very detrimental and caused less than a 10% increase in the losses due to the leakage injection relative to the steady calculations.
The Effects of Unsteadiness and Compressibility on the Interaction Between Hub Leakage and Mainstream Flows in High-Pressure Turbines
Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the JOURNAL OF TURBOMACHINERY. Manuscript received April 29, 2012; final manuscript received January 28, 2013; published online September 13, 2013. Editor: David Wisler.
- Views Icon Views
- Share Icon Share
- Cite Icon Cite
- Search Site
Popović, I., Hodson, H. P., Janke, E., and Wolf, T. (September 13, 2013). "The Effects of Unsteadiness and Compressibility on the Interaction Between Hub Leakage and Mainstream Flows in High-Pressure Turbines." ASME. J. Turbomach. November 2013; 135(6): 061015. https://doi.org/10.1115/1.4024636
Download citation file:
- Ris (Zotero)
- Reference Manager