Session: 12-01 Experimental studies on film cooling

Paper Number: 122413

122413 - Enhanced Adiabatic Film Cooling Effectiveness by Varying Compound Angle 

Effusion cooling is the state-of-the-art cooling technology for gas turbines. However, the compound angle of effusion cooling holes is commonly defined as a fixed value in prior studies. In particular, the compound angle is mostly set to zero in practice by assuming that highly directional miniature effusion cooling jets are aligned with the main flow direction. A recent study from our group has examined the directional effects of effusion cooling on adiabatic film cooling effectiveness (AFE) subjecting to a swirling main flow. It was found that a large compound angle initially facilitates a quick build-up of cooling film and the optimal compound angle reduced to smaller values downstream where the cooling film is fully developed. The current study exploits the new findings in the directional effects of effusion cooling by proposing novel effusion cooling designs with varying compound angles of cooling holes which are optimized for improving AFE along the main flow direction. In the present study, AFE was experimentally determined using Pressure Sensitive Paint (PSP) through invoking the heat/mass transfer analogy. The performances of two new effusion cooling designs were evaluated: 1) effusion cooling holes with three discrete compound angles, 90, 60, and 30 degrees, at three successive regions along the direction of the main flow, and 2) effusion cooling holes of gradually varying compound angles ranging from 90 to 30 degrees. 2D AFE maps resulting from the proposed designs were compared with those of conventional effusion cooling designs with various fixed compound angles under identical conditions. It was found that the new effusion cooling designs featuring varying compound angles produce a more uniform cooling film coverage and an enhanced AFE compared to the conventional effusion cooling designs at a relatively low blowing ratio (BR).

Presenting Author: Yeongmin Pyo University of Ottawa

Presenting Author Biography: Yeongmin Pyo is currently a visiting researcher and a graduate student at the National Research Council Canada (NRC-CNRC) and the University of Ottawa in Ottawa, Canada, respectively. He worked as a visiting researcher at NRC-CNRC in Ottawa, Canada since 2019. He worked as a research staff for Gangneung Wonju National University. He received his B.S. and M.S. degrees from Gangneung Wonju National University in Wonju, South Korea in 2013 and 2017, respectively. His main research interest is the development of advanced cooling technology in the field of the gas turbine.

Authors:

Yeongmin Pyo University of Ottawa
Mohsen Broumand National Research Council of Canada
Juchan Son University of Ottawa
Patrick Richer University of Ottawa
Bertrand Jodoin University of Ottawa
Zekai Hong National Research Council of Canada