Tepe, Ahmet Umit2025-03-232025-03-2320221300-18841304-4915https://doi.org/10.17341/gazimmfd.831511https://search.trdizin.gov.tr/tr/yayin/detay/508630https://hdl.handle.net/11486/4971In this study, the effect of triangular concave ramp (UIBR) on film cooling efficiency (FSE) and flow characteristics in film cooling was numerically investigated. In order to protect the jet stream from the effect of the main stream, the UIBR is placed on the surface where the jet hole meets the surface and the main stream comes from. In order to determine the most suitable design parameters of the UIBR, three different inclination angles (ar) of 10 degrees, 25 degrees and 45 degrees, three different dimensionless ramp heights (h/d) as 0.15, 0.30 and 0.50 examined. However, calculations were performed at blowing ratios (M) of 0.30, 0.60, 0.85 and 1.25. In order to accurately determine the physical properties of the film cooling in accordance with the real operating conditions, air was used for the main flow and CO2 was used for the fluid injected to the surface in the calculations. Accordingly, the jet stream to main stream density ratio (YO) is 1.50. CO2 was injected into the surface through a circular jet hole with an angle of aj=35 degrees with the surface and a diameter of d=4 mm. Numerical studies were carried out using Ansys FLUENT developed for Computational Fluid Dynamics (CFD) and the Transition k-kl-omega turbulence model. The results are compared to a conventional flat surface without ramp. According to the numerical results, increasing the ramp height and decreasing the ramp angle significantly increased the FSE. As a result, the highest increase in area-averaged FSE compared to conventional film cooling was obtained as 305.44% in the ramp design with h/d=0.50 and ar=10 degrees.trinfo:eu-repo/semantics/openAccessFilm coolingFilm cooling effectivenessHeat transferGas turbine blade computational fluid dynamicsArticle3731263127510.17341/gazimmfd.8315112-s2.0-85128736776Q2508630WOS:000834843300011Q3