The Effect of Rotor Leakage Flows on Hot Gas Ingestion

This is the authors' abstract. We don't add key points for this paper.

The geometry of a turbine rotor disc has spaces through which parasitic leakage flows can leave the upstream disk cavity, affecting the purge flow required to maintain acceptable cavity temperatures. This paper presents a study of the effects of leakage flows through gas turbine rotors on hot gas ingestion into rotor-stator cavities. By modulating the area of rotor leakage paths, it is shown experimentally and numerically that, as expected, rotor leakage increases the purge flow required to maintain acceptable average cavity temperatures. However, the study also shows that through disc leakage exacerbates the effects of non-uniform ingestion, increasing the magnitude of local peaks in surface temperature for a given cavity average value. An empirical low-order model is proposed for the flow in the rotorstator cavity which captures the sensitivity of seal effectiveness to purge flow when leakage is present.