Numerical Simulation Of Characteristics Of Flow And Heat Transfer Of Film-Cooling

Film cooling is mostly used for protecting the blade erosion for hot gas in gas turbine, it is importent for devising the blade while predict cooling effect precisely. Numerical simulation was performed to investigate the flow and heat transfer characteristics of a round hole of film-cooling, using Standard k -ε,RNG k -εand Realizable k -εturbulence models, and the results were compared and analyzed to decade which one is best to compute the jet-to-crossflow; Through comparing and analyzing the temperature fields of converage hole,round hole and cone holes, characteristics of temperature fields of different holes with different blowing ratios were studayed; And Large Eddy Simulation (LES) was performed to investigate the development process of vortices on different sections of a round hole and a cone-shaped holes withγto be 30o.The results suggested that when simulating the cross flow which exist separate flow and back flow, the RNG k -εturbulence model obtained improved prediction than the Standard k -εmodel'. For the round holes, the smaller blowing ratio was, the more jet trajectories close to the wall was, and the greater cooling effectiveness was. At the same blowing ratios, the flow fields of cone hole was more stability than the round especrally the converage hole's, the cooling effectiveness of the cone hole was superior to the two holes's. The cone hole had an optimal jet-to-crossflow blowing ratio, about 0.7 to make the cooling effectiveness highest, for arrangement of single hole, a cone hole withγto be 30o was the optimal jet hole, for arrangement of rows holes, a cone hole withγto be 60o geometries was the optimal. The positive and negative vortices in the centreplane and the two wings of the horseshoe vortices in the vertical profiles were shed off new vortices alternately and periodicly, the time of sheding off of cone hole's was less than the round hole's at the someprofile, the acting of jet and crossflow was more acuity in the near wall, so carried off more energy, then enhanced t he film cooling effectiveness.