Analysis of the hot gas ingress into the wheel space of an axial turbine stage

Abstract

The thermal efficiency of gas turbines strongly depends on the turbine inlet temperature. Increasing the inlet gas temperature improves the engine performance, but results in new challenges for the cooling of the turbine material. To avoid hot gas ingress from the main annulus flow into the wheel space between the stator and the rotor disks, which can lead to machine failure, cooling air from the turbine’s secondary air system is used to seal the rim seal gap and to cool the wheel space. To increase the thermodynamic efficiency of the turbine, it is necessary to minimize the cooling mass flow rate.