Experimental investigation of sequential narrow impingement channels for turbine cooling

Michele Gaffuri; Peter Ott; Shailendra Naik; Marc Henze

doi:10.29008/ETC2021-523

14^th European Conference on Turbomachinery Fluid dynamics & Thermodynamics

Paper ID:

ETC2021-523

Main Topic:

Heat Transfer & Cooling

https://doi.org/10.29008/ETC2021-523

Authors

Michele Gaffuri - Thermal Turbomachinery GroupEPFL - Swiss Federal Institute of Technology
Peter Ott - Thermal Turbomachinery GroupEPFL - Swiss Federal Institute of Technology
Shailendra Naik - Ansaldo Energia Switzerland, Haselstrasse 18, CH-5400 Baden
Marc Henze - Ansaldo Energia Switzerland, Haselstrasse 18, CH-5400 Baden

Abstract

Sequentially stacked impingement channels allow for a more effective use of the cooling fluid and can limit the heat transfer reduction due to the crossflow when the number of jets increases. In this paper, sequential impingement channels are experimentally investigated using the transient liquid crystal technique. Twelve configurations are tested: the baseline consists in a double rectangular channel with 5 jets per channel; other configurations feature different number of jets, variations of the jet-to-jet spacing and of the transition zone length, reduction of the cross-section in the transition zone and addition of a bypass between the channels. Results show that heat transfer coefficients (HTC) in the2nd channel are similar to the 1st, and that the cross-section reduction in the transition zone allows for an increase of the HTC in this critical zone with a moderate increase of pressure losses.