Experimental Measurements of Ingestion Through Turbine Rim Seals--Part II: Rotationally Induced Ingress.

Autor: Sangan, Carl M., Pountney, Oliver J., Zhou, Kunyuan, Owen, J. Michael, Wilson, Mike, Lock, Gary D.
Předmět:
Zdroj: Journal of Turbomachinery; Mar2013, Vol. 135 Issue 2, p1-9, 9p
Abstrakt: Part I of this two-part paper presented experimental results for externally-induced (EI) ingress, where the ingestion of hot gas through the rim seal into the wheel-space of a gas turbine is controlled by the circumferential variation of pressure in the external annulus. In Part II, experimental results are presented for rotationally-induced (Rl) ingress, where the ingestion is controlled by the pressure generated by the rotating fluid in the wheel-space. Although EI ingress is the common form of ingestion through turbine rim seals, RI ingress or combined ingress (where El and RI ingress are both significant) is particularly important for double seals, where the pressure asymmetries are attenuated in the annular space between the inner and outer seals. In this paper, the sealing effectiveness was determined from concentration measurements, and the variation of effectiveness with sealing flow rate was compared with theoretical curves for Rl ingress obtained from an orifice model. Using a nondimensional sealing parameter f0 the data could be collapsed onto a single curve, and the theoretical variation of effectiveness with f0 was in very good agreement with the data for a wide range of flow rates and rotational speeds. It was shown that the sealing flow required to prevent Rl ingress was much less than that needed for EI ingress, and it was also shown that the effectiveness of a radial-clearance seal is significantly better than that for an axial-clearance sea! for both El and Rl ingress. [ABSTRACT FROM AUTHOR]
Databáze: Supplemental Index