Abstract
Experimental activity has been performed to study different impingement cooling schemes in static and rotating conditions. Geometry replicates a leading-edge cold bridge system, including a radial supply channel and five rows of film-cooling and showerhead holes. Two impingement geometries have been studied, with different numbers of holes and diameters but with equal overall passage area. Reynolds numbers up to 13,800 and rotation numbers up to 0.002 have been investigated (based on an equivalent slot width). Tests have been performed using a novel implementation of transient heat transfer technique, which allows correct replication of the sign of buoyancy forces by flowing ambient temperature air into a preheated test article. Results show that complex interactions occur between the different features of the system, with a particularly strong effect of jet supply condition. Rotation further interacts with these phenomena, generally leading to a slight decrease in heat transfer.
Highlights
IntroductionCurrent performance levels of gas turbine engines, both in terms of thermal cycle efficiency and specific power output, have been reached thanks to an increase in turbine inlet temperature
Current performance levels of gas turbine engines, both in terms of thermal cycle efficiency and specific power output, have been reached thanks to an increase in turbine inlet temperature.The downside of this trend is the intensification of thermal loads on the engine components, which require the development of more effective cooling systems to be managed
The heat transfer surface is unrolled on a flat plane, where the horizontal coordinate S represents the distance along the surface itself from its extremity close to the pressure side (PS), while the vertical coordinate Z is along the outward radial direction
Summary
Current performance levels of gas turbine engines, both in terms of thermal cycle efficiency and specific power output, have been reached thanks to an increase in turbine inlet temperature The downside of this trend is the intensification of thermal loads on the engine components, which require the development of more effective cooling systems to be managed. Coriolis forces act on the flow inside the radial supply channel, which can lead to an uneven supply condition for the impingement jets [11] All of these studies demonstrate that rotational effects are difficult to predict, since rotation acts on the different and interacting features of the system: the whole cooling device needs to be replicated in order to perform a reliable investigation. The effect of impingement hole number and diameter has been determined by comparing two impingement geometries with a different hole pattern but with the same overall passage area
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
