Investigation On Flow And Heat Transfer Characteristics Of Intenal Cooling Structures Of Turbine Vane

The gas turbine inlet temperature is keeping increasing with the development of aviation industry and performance of aero gas turbine engine, which is a challenge for the long-term and stable operation of gas turbine. Exploring innovative and highly efficient cooling structure, as well as developing new materials and producing technology, is necessary to solve this issue. Cooling structure of inner composition cooling + outer film cooling is applied in gas turbine vane. The flow and heat transfer characteristics is complicated in inner structure with incorporated cooling manners so that the research of reasonable organization and distribution of coolant in the vane becomes the key to develop innovative and highly efficient cooling structures for turbine vane.In this paper, numerical simulation is performed aiming to the four near wall cooling structures in turbine vane in the mid-chord region. The results show that different near wall cooling structures greatly influenced the cooling effect on blade surface. The cooling structure integrating impingement, pin-fins, and outer film cooling appears more predominant comprehensive cooling performance of near wall cooling than the other three structures with more uniform temperature and low pressure drop. Furthermore, the effect of parameters of pin-fin and impingement holes on the influence of flow and heat transfer characteristic is analyzed of the laminate structure with impingement holes, pin-fins and film cooling. Furthermore, full size vane with two different inner cooling structures(vortex chamber and laminate plate) are numerical simulated and its flow and heat transfer discipline are analyzed. Diameter and spacing of impingement holes less affected temperature distribution on the blade surface with constant perforated ratio. Flow resistance of cooling air increases with increasing of diameter and spacing of impingement holes. Cooling performance of laminate structure gets worse with larger diameter and hole-angle with constant opening ratio. Stricture with circular pin-fin has the lowest flow resistance at the constant blockage ratio. Comparing the cooling efficiency of the cooling structure in the full size vane, the structure of laminate is better than the vortex chamber.Finally, experimental study is carried out to analyze the representative parameters of laminate structure with the effect of blowing ratio, pin-fin and impingement hole-size. The experimental results show that laminate plate wall temperature decreases with the increasing of blowing ratio. With the increasing of blowing ratio, comprehensive cooling performance of near wall cooling increases but increasing trend becomes small. Experiment data shows the lowest flow resistance with circular pin-fin of laminates structure and largest flow loss with racetrack shaped pin-fin. It also shows that diamond pin-fin of laminate structure has the largest cooling efficiency. Diameter and spacing of impingement holes have little effect on the comprehensive cooling performance of laminate. Flow loss is biggest with 1mm of impingement hole-diameter and is least with 0.6mm. The greater the number of film cooling holes, the more uniform wall temperature distribution and better comprehensive cooling performance of near wall cooling becomes. Film cooling hole-angle of 30°is best for cooling effectiveness but the flow loss is bigger.