| 摘要 |
A gas turbine blade for a combined cycle, capable of being cooled effectively by a suitable quantity of steam, wherein cooling steam flow passages (a) are provided therein, into which cooling steam is supplied so as to cool the gas turbine blade from the inner side thereof, characterized in that a ratio (t/c) of a thickness (t) of the gas turbine blade to a chord length (c) is 0.15 or below. The velocity of flow of the cooling steam increases as the above ratio (t/c) decreases by assuming that the flow rate of the cooling steam flowing in the interior of the cooling steam flow passages (a) is constant. A heat transfer coefficient of an inner surface of the turbine blade also increases in the same manner in this case. Therefore, when the ratio (t/c) is 0.15 or below, which corresponds to a minimum heat transfer coefficient ( alpha 1) required of turbine blade cooling performance, the turbine blade is effectively cooled and a low flow rate of the steam suitable for a combined cycle can be maintained. Especially, the ratio (t/c) is preferably within the range of 0.10-0.15, and the recovered steam can be effectively reused. |
