Improvement in thermal hydraulic performance by using continuous V and W-Shaped rib turbulators in gas turbine blade cooling application

Abstract

Power output and efficiency of a gas turbine can be improved by employing ribs that have the potential to generate high Thermal Hydraulic Performance (THP). The objective of this experimental work is to achieve high THP in a narrow cooling passage adjoining the leading edge where the operating temperatures are high. To achieve this objective, experiments are conducted in a single-pass cooling channel having aspect ratio (AR) 1:4 and hydraulic diameter (Dh) 0.048 m with V and W-ribs placed on opposite walls facing downstream. Angle-of-attack (α) for the ribs is 45° and the blockage ratio (e/Dh) for V-ribs is 0.0729 and for W-ribs is 0.0833. Pitch-to-height ratio (P/e) for V-ribs is 10 and W-ribs is 8.75. For the Reynolds number range 20000–80000 investigated, V and W-ribs produced high heat transfer enhancements. Maximum Nusselt number ratios for V-ribs and W-ribs are 3.9 and 3.8. Variations in heat transfer along the span and stream are found to be higher for V-ribs and W-ribs respectively. For both the cases, influence of ribs on heat transfer and friction is observed to be highest at Reynolds number 40000. Maximum THP values achieved for V-ribs and W-ribs are 3.3 and 3.