| 摘要 |
PROBLEM TO BE SOLVED: To improve the heat transfer coefficient of cooling medium and provide an excellent cooling performance with a limited cooling medium in a turbine cooling blade having a blade passage in a blade by forming a clearance on at least one side of both side walls of heat transfer promoting rib provided in the crossing direction of a cooling medium carried in the blade passage. SOLUTION: A turbine cooling blade 21 has a blade passage 23 formed into a box. A heat transfer promoting rib 24 is provided in the crossing direction of a cooling medium CF carried from the inner diameter side to the outer diameter side of the blade passage 23, and the heat transfer promoting rib 24 has a clearance on one side between its edge 25a, 25b and side walls 22a, 22b. The clearance 26 is set to a range of t=(0.05-0.2)×L when its width is (t) and the width of the blade passage 23 is L. Thus, the heat transfer coefficient of the cooling medium CF is significantly improved by a flow line F1 jumping over the heat transfer promoting rib 24, a flow line F2 passing the clearance 26, and a part of the outlet side circulating flow mixed with the flow line F1 as an ascending flow line F3 by the flow line F2 .
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