V-Spline Design for Enhanced Performance in Turbine Blade Internal Cooling

Abstract

Past experiments have consistently shown that V-shaped rib turbulators are among the best in heat transfer performance. While there is literature on the V rib design in various experimental studies, there is no literature that shows the V rib design applied on any current turbine blades. Instead, the straight and angled rib design are used. The V rib only offers a marginally better heat transfer performance over the angled rib, but it has a severe stress concentration at the rib tip. In this research, multiple design augmentations were analyzed, with the addition of a spline at the center of the V exhibiting alleviation of the tip stress concentration. The results show that the presence of the spline not only resolves the fatigue issues but also increases the heat transfer performance by 4.3% and 8.2% against the V rib and angled rib design, respectively. With a better heat transfer performance, the creep analysis shows that the turbine blade with a V-spline rib design can operate at temperatures 203 °C hotter than an angled rib at the same fluid power. Given the dependence of engine thermal efficiency on turbine inlet temperature, this simple design shows good potential for heat transfer augmentation.