Impinging cooling of film hole surface using transient liquid crystal thermograph

Effects of film hole arrangement and geometry on impingement heat transfer along a film hole surface are experimentally investigated in detail. A transient liquid crystal thermograph technology has been used in the experiment for present investigation. The film hole size with four different values, 1.5, 2.0, 2.5, 3.0 mm, jet Reynolds number ranging from 2000 to 4000, and jet-to-target spacing ranging from 1.5 to 4.5 are considered to study the impingement heat transfer performance. In addition, three arrangements of film hole on the target plates, named side-, middle- and staggered-types, are tested, respectively. The experimental results show that the Nusselt number increases with the increase of jet Reynolds number as well as the decrease in jet-to-plate spacing. Better heat transfer can be achieved with larger film hole size. As for the effect of the arrangement of film holes on the target surface, the heat transfer on side-type plate is more significant than the other two for smaller jet-to-plate spacing.