Large eddy simulation of film cooling flow from a fanshaped hole

• Published in: Applied thermal engineering 2018-01, Vol.129, p.855-870
• Main Authors: Wang, Chunhua, Zhang, Jingzhou, Feng, Hongke, Huang, Ying
• Format: Article
• Language: English
• Subjects: Analysis; Coherent structures; Cooling; Fanshaped hole; Film cooling; Flat plates; Fluid dynamics; Fluid flow; Horseshoe vortices; Large eddy simulation; Periodic variations; Plates (structural members); Reynolds number; Simulation; Time-frequency analysis; Velocity
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2017.10.088

•LES method is used for simulating film cooling of a fanshaped hole.•Coherent structures for film cooling of fanshaped hole is analyzed in detail.•Time frequency analysis of fluctuation signals for film cooling of fanshaped hole is performed. Large eddy simulation was applied for studying interaction between hot crossflow and coolant jet from a fanshaped hole. Simulations were performed at two blowing ratios, M=0.5 and 1.5, and the Reynolds number, Re=45674, based on the crossflow velocity and hole diameter. Downstream of shaped hole, plenty of hairpin vortexes distribute disorderly on the flat plate, and form ‘forests of hairpin vortexes’. Roller vortexes and horseshoe vortexes are the important structures in the near filed region. Because of low jet velocity, fanshaped holes show weaker roller vortexes and horseshoe vortexes compared with round holes. In the far filed region, small-scale vortexes originating from break up of large-scale coherent structures take the dominant role. The projections of vortexes on vertical, spanwise and streamwise directions for fanshaped hole were discussed in detail. By time–frequency analysis of velocity fluctuation signals, the dominant frequency for fanshape holes is indistinct, and periodicity of film cooling of shaped holes is weaker than that of round hole.