Heat transfer characteristics of a dimpled/protrusioned pin fin wedge duct with different converging angles for turbine blades

A numerical method is utilized to investigate the converging angle effects on the flow structure and heat transfer of a pin fin wedge duct with dimples/protrusions. The studied converging angles are (Formula presented.) (Formula presented.) and (Formula presented.) The results show that a pin fin-dimple wedge duct with larger converging angle produces higher heat transfer enhancement due to flow acceleration, increase of the impingement region, and shrinkage of the flow recirculation region, but it is also accompanied with a much larger friction factor. A pin fin-protrusion wedge duct with larger converging angle yields higher heat transfer augmentation due to flow acceleration and more intense impingement on the protrusion but it is also associated with larger pressure penalty.