TY - JOUR
T1 - Large eddy simulation of compound angle effects on cooling effectiveness and flow structure of fan-shaped holes
AU - Zamiri, Ali
AU - Chung, Jin Taek
N1 - Funding Information:
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education ( 2020R1I1A1A01060578 ).
Publisher Copyright:
© 2021
PY - 2021/10
Y1 - 2021/10
N2 - Large eddy simulation (LES) was utilized to investigate the influence of applying various compound angle (CA), on film-cooling effectiveness and turbulent flow structures. The baseline cooling hole was a 7-7-7 laidback fan-shaped hole, where this hole is located at a flat plate surface with a pitchwise spacing of 6D, and the hole was inclined at 30-degrees with respect to the mainstream hot-gas flow. Five different cooling hole orientations (CA0, CA15, CA30, CA45 and CA60) were numerically simulated using a constant density ratio of 1.5 and two blowing ratios (M = 1.0 and 3.0). The time-averaged computational results for the thermal and flow fields were validated by comparison with experimental data from previous literature. The simulation results revealed that under a low blowing ratio (M = 1.0), cooling performance was not affected significantly by the compound angle, but at the higher blowing ratio there was a considerable improvement of 40% for the CA60 hole over the CA0 hole, this improvement was especially pronounced in the lateral direction. The vorticity-field investigation showed that as the compound angle increased, the magnitude of the streamwise vorticity also increased while it becoming more asymmetric. In addition, time-space evaluation and spectral analysis of the velocity fluctuations indicates higher unsteadiness and greater turbulent statistics when using holes with larger compound angles.
AB - Large eddy simulation (LES) was utilized to investigate the influence of applying various compound angle (CA), on film-cooling effectiveness and turbulent flow structures. The baseline cooling hole was a 7-7-7 laidback fan-shaped hole, where this hole is located at a flat plate surface with a pitchwise spacing of 6D, and the hole was inclined at 30-degrees with respect to the mainstream hot-gas flow. Five different cooling hole orientations (CA0, CA15, CA30, CA45 and CA60) were numerically simulated using a constant density ratio of 1.5 and two blowing ratios (M = 1.0 and 3.0). The time-averaged computational results for the thermal and flow fields were validated by comparison with experimental data from previous literature. The simulation results revealed that under a low blowing ratio (M = 1.0), cooling performance was not affected significantly by the compound angle, but at the higher blowing ratio there was a considerable improvement of 40% for the CA60 hole over the CA0 hole, this improvement was especially pronounced in the lateral direction. The vorticity-field investigation showed that as the compound angle increased, the magnitude of the streamwise vorticity also increased while it becoming more asymmetric. In addition, time-space evaluation and spectral analysis of the velocity fluctuations indicates higher unsteadiness and greater turbulent statistics when using holes with larger compound angles.
KW - Compound angle
KW - Gas turbine
KW - Laidback fan-shaped hole
KW - Large eddy simulation
UR - http://www.scopus.com/inward/record.url?scp=85109199756&partnerID=8YFLogxK
U2 - 10.1016/j.ijheatmasstransfer.2021.121599
DO - 10.1016/j.ijheatmasstransfer.2021.121599
M3 - Article
AN - SCOPUS:85109199756
SN - 0017-9310
VL - 178
JO - International Journal of Heat and Mass Transfer
JF - International Journal of Heat and Mass Transfer
M1 - 121599
ER -