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As the state of the art internal cooling configuration the serpentine passage with angled ribs has been developed for many decades and is now widely used in almost all the blade internal cooling applications. To further increase the thermal efficiency of gas turbine, the development of new internal cooling configurations is necessary. In the present study, a new internal cooling configuration, which is characterized by placing modified wedge-shaped detached ribs above the grooves, has been obtained and investigated. Under this new cooling configuration, the main effect for enhancement of heat transfer in standard ribbed channel, the separation and reattachment of the main flow, has been retained. Additional improvements can be found in several areas as follows: (1) flow near rib corner is not stagnant anymore and both corner vortexes near the rib have been eliminated, (2) the increased velocity in groove leads to locally high heat flux. With the same channel dimension, ribs pitch-height ratio, boundary conditions and the Reynolds number based on hydraulic diameter the new cooling configuration shows higher Nusselt number ratio at the ribbed wall by approximately 25–32%. The globally-averaged thermal performance parameter shows a 19–25% better heat performance by this kind of cooling configuration.Copyright © 2014 by ASME |
