Exploitation of Mainstream/Seal Flow Interactions for Reduced Ingestion

In turbines, stators and rotors must be installed with a clearance to prevent
rubbing and allow for smooth rotation. Consequently, a pathway for hot
gases from the mainstream into the cavity between disks is created. The net
movement of mainstream gas into the disk cavity is referred to as hot gas
ingestion. This is prevented using a purge flow, at the detriment of overall
efficiency. Hence it is necessary to design turbine rim seals which reduce
the required purge flow rate. Recent works of literature indicate that the
difference in swirl between the mainstream and seal flows contributes to
ingestion. Understanding this mechanism is crucial for designing improved
seals which require less purge flow to mitigate ingestion.