Enhanced thermal hydraulic performance by V-shaped protrusion for gas turbine blade trailing edge cooling

Abstract

Modern high-pressure stage gas turbine blades are equipped with several high-performance cooling concepts, which vary based on the external heat load and the blade-topology. Blade trailing edge cooling is challenging due to the space constraints, where channel aspect ratio (AR: channel width-to-height ratio) is ~ 4:1. With an aim to enhance the thermal hydraulic performance of such narrow channels, a novel V-shaped protrusion configuration is proposed in the present study. The V-shaped protrusion derives its profile from a known concept V-shaped concavity. Numerical investigation of inline configurations of V-shaped concavities and protrusions has been carried out for a 4:1 AR channel for Reynolds number ranging from 10,000 to 60,000. The configurational parameters of both concavity and protrusion were identical. Concavity/protrusion depth-height-to-diameter (δ/D) ratio was 0.3. The streamwise (Sx) and spanwise (Sy) pitch values were 3.2D in both the configurations. The fluid flow and heat transport in the two cooling configurations are discussed in detail. Globally averaged Nusselt number, friction factor and thermal-hydraulic performance have been reported for the investigated Re range. Results show that V-shaped protrusion had the highest thermal-hydraulic performance ~ 2.23, which was about 40.4% higher than the V-shaped concavity configuration for a representative Reynolds number of 10,000.