Enhancement of film cooling effectiveness using backward injection holes

Sehjin Park, Eui Yeop Jung, Seon Ho Kim, Ho Seong Sohn, Hyung Hee Cho

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

5 Citations (Scopus)


Film cooling is a cooling method used to protect the hot components of a gas turbine from high temperature conditions. For this purpose, high and uniform film cooling effectiveness is required to protect the vanes/blades from excessive thermal stress. Backward injection is proposed as one of the methods for the improvement of film cooling effectiveness. In this study, experiments were performed to investigate the effect of backward injection on film cooling effectiveness, using pressure sensitive paint (PSP) method. Four experimental configurations were composed of forward and backward injection cylindrical holes. The cylindrical holes were aligned in two staggered rows with pitch (p) of 6d and row spacing (s) of 3d. The injection angles (?) of the cylindrical holes were 35° and 145° for forward and backward injection, respectively. The blowing ratios (M) ranged from 0.5 to 2.0 and the density ratio (DR) was about 1. The results indicate that backward injection enhanced not only film cooling effectiveness but also the lateral cooling uniformity. At a high blowing ratio, all configurations demonstrated higher film cooling effectiveness with backward injection than with only forward injection; thus, the dispersion of the backward injection jets enhanced the lateral coverage over wide areas. Configuration, in particular, arranged with forward injection in the first row and backward injection in the second row, obtained the highest film cooling effectiveness among the four cases studied, due to the dispersion of the backward injection jets and the coolant supply from the forward injection jets at a high blowing ratio.

Original languageEnglish
Title of host publicationHeat Transfer
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791856727, 9780791856727
Publication statusPublished - 2015
EventASME Turbo Expo 2015: Turbine Technical Conference and Exposition, GT 2015 - Montreal, Canada
Duration: 2015 Jun 152015 Jun 19

Publication series

NameProceedings of the ASME Turbo Expo


OtherASME Turbo Expo 2015: Turbine Technical Conference and Exposition, GT 2015

Bibliographical note

Publisher Copyright:
© 2015 by ASME.

All Science Journal Classification (ASJC) codes

  • Engineering(all)


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