TY - GEN
T1 - Injection angle influence of secondary holes on the enhancement of film cooling effectiveness with horn-shaped or cylindrical primary holes
AU - Zhu, Rui
AU - Xie, Gongnan
AU - Simon, Terrence W.
N1 - Publisher Copyright:
© 2017 ASME.
PY - 2017
Y1 - 2017
N2 - Secondary holes to a main film cooling hole are used to improve film cooling performance by creating anti-kidney vortices. The effects of injection angle of the secondary holes on both film cooling effectiveness and surrounding thermal and flow fields are investigated in this numerical study. Two kinds of primary hole shapes are adopted. One is a cylindrical hole, the other is a horn-shaped hole which is designed from a cylindrical hole by expanding the hole in the transverse direction to double the hole size at the exit. Two smaller cylindrical holes, the secondary holes, are located symmetrically about the centerline and downstream of the primary hole. Three compound injection angles (á=30o, 45o and 60o, â=30o) of the secondary holes are analyzed while the injection angle of the primary hole is kept at 45o. Cases with various blowing ratios are computed. It is shown from the simulation that cooling effectiveness of secondary holes with a horn-shaped primary hole is better than that with a cylindrical primary hole, especially at high blowing ratios. With a cylindrical primary hole, increasing inclination angle of the secondary holes provides better cooling effectiveness because the anti-kidney vortices created by shallow secondary holes cannot counteract the kidney vortex pairs adequately, enhancing mixing of main flow and coolant. For secondary holes with a horn-shaped primary hole, large secondary hole inclination angles provide better cooling performance at low blowing ratios; but, at high blowing ratios, secondary holes with small inclination angles are more effective, as the film coverage becomes wider in the downstream area.
AB - Secondary holes to a main film cooling hole are used to improve film cooling performance by creating anti-kidney vortices. The effects of injection angle of the secondary holes on both film cooling effectiveness and surrounding thermal and flow fields are investigated in this numerical study. Two kinds of primary hole shapes are adopted. One is a cylindrical hole, the other is a horn-shaped hole which is designed from a cylindrical hole by expanding the hole in the transverse direction to double the hole size at the exit. Two smaller cylindrical holes, the secondary holes, are located symmetrically about the centerline and downstream of the primary hole. Three compound injection angles (á=30o, 45o and 60o, â=30o) of the secondary holes are analyzed while the injection angle of the primary hole is kept at 45o. Cases with various blowing ratios are computed. It is shown from the simulation that cooling effectiveness of secondary holes with a horn-shaped primary hole is better than that with a cylindrical primary hole, especially at high blowing ratios. With a cylindrical primary hole, increasing inclination angle of the secondary holes provides better cooling effectiveness because the anti-kidney vortices created by shallow secondary holes cannot counteract the kidney vortex pairs adequately, enhancing mixing of main flow and coolant. For secondary holes with a horn-shaped primary hole, large secondary hole inclination angles provide better cooling performance at low blowing ratios; but, at high blowing ratios, secondary holes with small inclination angles are more effective, as the film coverage becomes wider in the downstream area.
KW - Compound Angle
KW - Film Cooling
KW - Horn-Shaped Holes
KW - Interactions Of Vortices
KW - Secondary Holes
UR - http://www.scopus.com/inward/record.url?scp=85041005846&partnerID=8YFLogxK
U2 - 10.1115/IMECE2017-70734
DO - 10.1115/IMECE2017-70734
M3 - 会议稿件
AN - SCOPUS:85041005846
T3 - ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE)
BT - Heat Transfer and Thermal Engineering
PB - American Society of Mechanical Engineers (ASME)
T2 - ASME 2017 International Mechanical Engineering Congress and Exposition, IMECE 2017
Y2 - 3 November 2017 through 9 November 2017
ER -