In this study, a comparison of aerodynamic loss of gas turbine vane with various trailing edge configurations was experimentally performed. For the trailing edge, three cooling schemes (the cutback slot, the central injection slot, and the pressure side hole) and three levels of trailing edge diameter (7.5, 10.0, and 12.5% of the throat width, respectively) were considered. The total pressure loss was measured in a five-vane linear cascade at the low-speed mainstream condition (20 m/s) using a Kiel probe and a two-axis traversing device. The measurement region was constrained to the near mid-span region, and the measurement step size was 1 mm. The results showed that the distribution of the total pressure loss was strongly affected by cooling schemes. The vane with the pressure side hole showed a similar distribution to that of the baseline in which a cooling scheme was not applied. It was also shown that the total pressure loss increased as the trailing edge diameter increased regardless of the cooling schemes. Except for the cutback slot cases, there was an inflection point at which the tendency of the area-averaged total pressure loss to the blowing ratio was changed. Through the present study, correlation equations for each cooling scheme were derived against the trailing edge diameter and the blowing ratio.

This study experimentally investigated the effects of geometric parameters of an inclined slot on film cooling effectiveness (FCE) and proposed an optimal slot configuration using a Kriging model. The experiment was designed using the Box–Behnken design, incorporating three geometric parameters—the injection angle (α), inlet edge fillet radius (RL,in), and outlet edge fillet radius (RL,out)—at four blowing ratio conditions (M = 0.25, 0.5, 1.0, and 2.0). The FCE distributions were measured on a flat plate test section using the pressure sensitive paint technique, with a mainstream velocity of 30 m/s and a turbulence intensity of 12% conditions. The results showed that the injection angle was the dominant factor governing cooling performance, as 30° inclined slots consistently exhibited higher FCE than those of 60° inclined slots, regardless of edge geometry. The inlet edge fillet radius had little influence at low blowing ratios but became significant at higher ratios when combined with a large outlet fillet radius. The outlet edge fillet radius demonstrated a dual effect—moderate shaping improved near-exit coverage, whereas excessive shaping enlarged the exit area, reduced jet momentum, and lowered FCE downstream. The Kriging optimization predicted the optimal slot configurations for each blowing ratio, all featuring an injection angle of 30°. Results of validation tests showed that FCE was enhanced by ∼28% over the baseline.