FILM COOLING FOR A CYLINDRICAL HOLE WITH DOWNSTREAM CRESCENT-SHAPED BLOCK WITH PERPENDICULAR CROSSFLOW

Recent studies reveal that an internal coolant crossfl ow plays an important role in the fl ow fi eld and fi lm cooling
performance in the near-hole region. In the present paper a single array of cylindrical holes with crescent-shaped
blocks downstream is considered. The cooling performance under the quiescent coolant plenum conditions with a
perpendicular coolant crossfl ow are studied numerically at the blowing ratios 0.5–2.5. The height-to-diameter ratio
of the crescent-shaped block varies from 0.25 to 1.0 with an interval of 0.25. Based on the numerical results, it may
be deduced that a perpendicular crossfl ow induces an asymmetric pair of in-hole vortices and a biased coolant
coverage on the surface downstream of the hole exit. However, the bias direction depends on the value of the blowing
ratio. Compared with the quiescent plenum case, the perpendicular crossfl ow reduces the cooling performance, and
the benefi ts result from the crescent-shaped block downstream.
   
Author:  C. Zhang ,  P. F. Zhang ,  P. F. Ju
Keywords:  fi lm cooling, crescent-shaped block, cooling eff ectiveness, internal crossfl ow, numerical simulation
Page:  599