Measured Film Cooling Effectiveness of Three Multihole Patterns

Abstract

As an advanced cooling scheme to meet increasingly stringent combustor cooling requirements, multihole film cooling has received considerable attention. Experimental data of this cooling scheme are limited in the open literature in terms of different hole patterns and blowing ratios. The heat-mass transfer analogy method was employed to measure adiabatic film cooling effectiveness of three multihole patterns. Three hole patterns differed in streamwise row spacing (S), spanwise hole pitch (P), and hole inclination angle (α), with the first pattern S∕P=2 and α=30°, the second S∕P=1 and α=30°, and the third S∕P=2 and α=150°. Measurements were performed at different blow ratios (M=1-4). Streamwise coolant injection offers high cooling protection for downstream rows. Reverse coolant injection provides superior cooling protection for initial rows. The effect of blowing ratio on cooling effectiveness is small for streamwise injection but significant for reversion injection.

Experimental study of full coverage film cooling optimization

“…It is possible to obtain the heat transfer coefficient h conv and the adiabatic wall temperature T aw from a linear extrapolation according to (4). When plotting T w versus ϕ conv , 1/h conv and T aw will respectively be the slope and the Y intercept.…”

“…A significant number (more than 2700 since 1970 according to [1]) of papers on film cooling are available. Most previous researches were carried out with an injection wall equipped with only one hole [2] or one or two rows of holes [3], and furthermore, with multi-rows of holes [4]. Generally, these studies focused on the effects of geometric factors and aerothermic factors on the performance of film cooling.…”

Multi-objective optimization of three rows of film cooling holes by genetic algorithm

“…The Yuzhen et al [16] results showed that the row spacing ratio affects the film cooling performance. They found that, better adiabatic cooling performance is achieved by using a smaller pitch, especially for the multi-hole patterns.…”

Experimental Analysis of a Tubular type of Evaporative Heat Exchanger

“…Ganic et al [4] formation over a horizontal tube and conducted experiments with sub cooled water film over an electrically heated horizontal cylinder. Adiabatic film cooling effectiveness of different patterns measured using heat-mass transfer analogy method determined by Lin et al [5], as an advanced cooling scheme to meet increasingly stringent combustor cooling requirements. Turbulent forced convective heat and mass transfer downstream of blockages with round and elongated holes in a rectangular channel was studied by Ahn et al [6].…”