Research for double wall cooling configuration with flower shaped ribs

Abstract

Excellent turbine cooling configuration protects turbine blade from the erosion of gas. Double wall cooling is a new cooling method which contains film cooling and impingement cooling. This paper proposes a double wall cooling configuration with flower shaped ribs which are different from traditional cylindrical ribs. A unit of flower shaped ribs contains single convex half ball rib and 4–7 bar shaped ribs, as a supplement, a double wall cooling configuration without rib is also researched for contrast. All of the configurations have original size and half size. Computational Fluid Dynamics is applied for research. The boundary condition of main flow refers the experiment of NASA, and coolant pressure is 1.01, 1.02, 1.05, 1.10, 1.15 and 1.20 times that of main flow pressure, and there is a quadric correlation between Blowing ratio(BR) and Coolant Pressure Ratio(CPR). Flow resistance and cooling effectiveness of configurations with/without ribs are compared firstly, then the performances of 4 kinds of flower shaped ribs(case 1∼case 4) are discussed. Results show that flow shaped ribs have little effects on flow resistance but increase cooling effectiveness by 10.9%–21%. The cooling performance of half sized configurations is more excellent than that of original sized configurations. The cooling effectiveness of case 2 and case 4 is higher by 6% than that of case 1 and case 3 averagely, because in case 2 and case 4, the vortex pair sizes are smaller and the negative effect of coolant meeting between two groups of flower shaped ribs is weaker. The results of the research provide the references to the design of turbine cooling configurations.