In gas turbine, the enhancement of durability and the increase of reliability represent essential requirements. These issues become even more critical for components subjected to high thermal loads, as the combustion chamber, and go in parallel with the desire for higher efficiency, which resulted in a reduced amount of air that the cooling systems designers have available for the combustor liner.
This work presents the results of an experimental campaign aimed to evaluate the performance on a portion of the combustion chamber liner of the latest Ansaldo Energia AE64.3A+ gas turbine. In this configuration ceramic tiles replace the previous metallic heat shields, reducing coolant consumption up to 40%.
The designed test article is made up of two ceramic bricks, held on the shells by means of air cooled metallic tile holders, and is installed in a dedicated plenum chamber where is run over by an air flow from several angles of incidence in order to simulate some realistic turbine conditions.
A preliminary numerical study is conducted to estimate the test article surface pressure distributions in order to evaluate the mainstream flow impact on the tile holder cooling system behaviour. A novel application of Pressure Sensitive Paint (PSP) technique is applied to evaluate the air seal cooling of the brick holder system, essential to prevent hot gas ingestion. Furthermore, infrared (IR) thermography measurements on the liner are performed using an hot mainstream flow and reproducing typical cooling flow conditions. During the tests, several thermocouples, allocated on most critic brick holder components, continuously check the metal temperature.