Numerical Investigation of Flow and Heat Transfer in Vane Impingement/Effusion Cooling with Various Rib/Dimple Structure

By investigating heat transfer and flow structures of dimples, orthogonal ribs, and V-shaped ribs in the impingement/effusion cooling, the article is dedicated to selecting a best-performing internal cooling structure for a turbine vane. The overall cooling effectiveness and coolant consumption are adopted to evaluate the cooling performance. To analyze the influence of structural modification, the flow field is investigated on chordwise/spanwise sections and the target surface. The blockage effect on crossflow can protect jet flow, resulting in higher heat transfer performance of the target surface. Ribs own a stronger blockage effect than dimples. Compared with the blockage effect, the influence of the rib shape is negligible. By installing dimples between ribs, heat transfer is augmented further. The introduction of ribs/dimples leads to higher discharge coefficients of jet nozzles but lower discharge coefficients of film holes. Thus, the film cooling deteriorates. Meanwhile, the installation of the ribs and dimples decreases total coolant consumption. The effect of ribs/dimples on heat transfer and effusion condition of internal and external cooling is analyzed. The best-performing cooling structure is the target surface with dimples and orthogonal ribs, which decreases the wall temperature and coolant consumption by 14.57-28.03 K and 1.19%-1.81% respectively. This article concludes the flow mechanism for dimples and influence factors on the cooling performance, which may serve as guidance for the turbine vane design.