Heat Transfer Characteristics of Pin-Fin Arrays with Ribs to Cool Combustor Liners

Abstract

Enhancement of heat transfer by pin-fin channels with turbulence promoters has been investigated with an aim to improve the cooling efficiency of combustor liners in gas turbines. Time-mean local Nusselt number profiles were obtained by naphthalene sublimation technique based on the heat/mass transfer analogy for Reynolds numbers ranging from 1000-10000. Two oblique rib-type turbulence promoters were tested and compared with no-rib cases. In addition, steady three-dimensional numerical simulations using a RANS model were performed. Installation of turbulence promoters is found to be effective in increasing the endwall heat transfer rate widely and uniformly. In addition, the ribs enhance heat transfer, especially in developing regions at the first and second pin-fin rows. Local high heat transfer regions were obtained in front of the ribs due to horseshoe vortices and downstream of the pins due to a longitudinal vortex.

Keywords

• pin-fins
• combustor
• jet engine
• heat and mass transfer
• naphthalene sublimation method