RT Journal Article ID 306984743c2a784c A1 Khamane, Hamza A1 Azzi, Abbes A1 Mansouri, Zakaria T1 NUMERICAL INVESTIGATION OF FILM-COOLING EFFECTIVENESS DOWNSTREAM OF A MICRO RAMP JF Computational Thermal Sciences: An International Journal JO CTS YR 2018 FD 2018-03-14 VO 10 IS 2 SP 151 OP 165 K1 film-cooling effectiveness K1 blowing ratio K1 micro ramp K1 RANS K1 turbine blades AB Gas turbine blades operate under high temperatures and thermal stresses caused by hot combustion gases issuing from the combustion chamber. A film-cooling technique is usually used to protect the surfaces of the blades and to avoid turbine damage. This paper investigates numerically the effect of a micro ramp (MR) on film-cooling performance in a jet-crossflow configuration. The configuration comprises an inclined coolant jet at 35° interacting with a hot crossflow. The micro ramp is placed downstream of the jet, where different heights of MR are investigated. The numerical simulations are carried out using Reynolds-averaged Navier-Stokes (RANS) technique with realizable k-ε as a turbulence closure model. Validations of the computational model with the experimental data are performed, and good agreement is found. The flow field and vortices downstream of the jet are analyzed for baseline and MR configurations. Results reported that the counter-rotating vortex pair (CRVP) is present for the baseline configuration and is not found inMR configurations. In addition, the flow field shows significant changes at each height of MR. Furthermore, the film-cooling effectiveness is analyzed and discussed according to the thickness, width, and inclination angle of the thermal layer (coolant jet) on the flat plate. It is found that the highest MR used is the most reliable and it enhances significantly the film-cooling effectiveness compared with the other MR configurations. Finally, the effect of two blowing ratios (M = 1 and M = 1.5) on film-cooling effectiveness is investigated. Results indicated that the maximum effectiveness is found at M = 1.5 with the highest MR (Ramp C). PB Begell House LK https://www.dl.begellhouse.com/journals/648192910890cd0e,00121d6d7622a434,306984743c2a784c.html