Injection angle influence of secondary holes on the enhancement of film cooling effectiveness with horn-shaped or cylindrical primary holes

Rui Zhu, Gongnan Xie, Terrence W. Simon

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

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.

Original languageEnglish (US)
Title of host publicationHeat Transfer and Thermal Engineering
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791858431
DOIs
StatePublished - Jan 1 2017
EventASME 2017 International Mechanical Engineering Congress and Exposition, IMECE 2017 - Tampa, United States
Duration: Nov 3 2017Nov 9 2017

Publication series

NameASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE)
Volume8

Other

OtherASME 2017 International Mechanical Engineering Congress and Exposition, IMECE 2017
CountryUnited States
CityTampa
Period11/3/1711/9/17

Keywords

  • Compound Angle
  • Film Cooling
  • Horn-Shaped Holes
  • Interactions Of Vortices
  • Secondary Holes

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