| 摘要 |
A cast turbine blade (10) comprises an internal cooling passage (12) that zig-zags or meanders through the blade from an inlet (14, 28) in the blade root R to an outlet (16) in the blade tip T. The cooling passage (12) has a zone (18) at a bend that is remote from the inlet (28) of the cooling passage when its distance from the inlet is measured around the passage, but that is closer to the inlet (28) when its distance from the inlet is measured in a straight line. During casting of the blade, the cooling passage (12) is defined by a core or cores comprising a leachable material, the cores being removed after casting by a chemical leaching process. A supplementary passage (22b) is also provided for connecting the remote zone (18) to the inlet (28) during the leaching process. The supplementary passage (22b) may likewise be defined by a leachable core, or it may be machined into the blade after casting. During the service life of the blade (10), a plug (30) obturates the supplementary passage (22b) to prevent leakage of cooling air from the cooling passage (12) through the supplementary passage. During the leaching process, the supplementary passage (22b) facilitates quicker and more thorough removal of core material from the remote zone (18) of the cooling passage (12). |
