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

Recent studies reveal that an internal coolant crossflow plays an important role in the flow field and film 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 crossflow 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 crossflow 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 crossflow reduces the cooling performance, and the benefits result from the crescent-shaped block downstream.
  Автор:  Zhang C. ,  Zhang P. F. ,  Ju P. F.
Ключевые слова:  film cooling, crescent-shaped block, cooling effectiveness, internal crossflow, numerical simulation
Стр:  614