The Aero-Thermal Performance of Purge Flow and Discrete Holes Film Cooling of Rotor Blade Platform in Modern High Pressure Gas Turbines: A Review

Abstract

Design of cooling systems for rotor platforms is critical due to the complex flow field and heat transfer phenomena related to the secondary flow structures originating at the blade leading edge. Horseshoe vortex and passage vortex are the fluid-dynamic features that largely influence the aerodynamic behaviour and the thermal protection level of the platform. The driving parameter is the coolant to mainstream momentum flux ratio, but several issues have to be considered in the design process of cooling technologies. As well acknowledged, an in-depth understanding of losses and heat transfer phenomena are deemed necessary to design effective cooling systems. In the present review, measurements and predictions on the behaviour of the HPT rotor cooled platform, obtained during the last two decades by several research groups, are gathered, described and analysed in terms of aerodynamic losses and heat transfer performance, and are compared with one another with respect to the effectiveness level that is ensured.

Rotor Cascade Assessment at Off-Design Condition: An Aerodynamic Investigation on Platform Cooling

“…The sealing flow emerging from the stator to the rotor interface gap interacts with the main flow, influencing both the aerodynamic and thermal performance of the rotor cascade. An exhaustive review of the available literature on this topic can be found in [8]. Loss for the blade row increases with the purge flow rate (see, for example, [9]) due to the strengthening of the horseshoe vortex-pressure side leg, which entraps most of the purge air.…”

Effect of Slot Jet Flow on Non-Axisymmetric Endwall Cooling Performance of High-Load Turbines

“…In recent years, to increase the thermal effectiveness of gas turbines due to the current vast energy needs, the turbine inlet temperature and pressure have become incredibly high [1][2][3]. Additionally, the technology used in diffusion burners has been updated to minimize NO x emissions, and it can cause a steadier turbine inlet temperature distribution and increase the heat load of endwall surfaces in turbines [4].…”