Full-Annular Numerical Investigation of the Rim Seal Cavity Flows Using GPU’s

In high pressure turbines to prevent the ingestion of the hot gas into the disk cavity cold air is purged from the cavities in-between the blade rows into the main flow. This numerical paper investigates this unsteady interaction between the main flow and the purge flow on a full-annular computational model of the LEC’s in-house axial turbine facility “LISA” at ETH Zurich. The simulations have been conducted on the GPU accelerated in-house solver “MULTI3”. One complete revolution of the 360° model could be completed in 48h using 18 GPU’s.Two injection rates have been considered. For the 0.9% injection rate a separation bubble has been captured at the cavity neck which triggered high frequency pressure fluctuations. The 20° model also predicted the high frequency fluctuations; however their amplitude was underestimated due to the forcing of the flow field to periodicity. On the other hand, at the low injection rate of 0.4% no considerable separation bubble was formed inside the cavity. The unsteady simulations have demonstrated the inherent unsteadiness in the purge flow - main flow interaction.Copyright © 2014 by ASME