In a turbine blade in which a tabular rib partitioning the blade into a pressure side and a suction side is provided in substantially the midsection of the blade along a center line connecting a leading edge and a trailing edge, and at least two cavities of which a cavity at the suction side and a cavity at the pressure side do not communicate with each other are provided, a pressure adjustment member for cooling air flowing into and out of the cavity at the suction side reduces the amount of cooling air flowing into the suction side, relative to the pressure side.
1. A turbine blade, comprising:
a tabular rib that partitions the turbine blade into a pressure side and a suction side, the tabular rib being provided along a center line connecting a leading edge and a trailing edge of the turbine blade and between the leading edge and the trailing edge;
at least two cavities of which a cavity at the suction side and a cavity at the pressure side do not communicate with each other;
a passage for cooling air supplied to the cavity at the pressure side and flowing out of a film-cooling hole at the pressure side of an air foil; and
a passage for cooling air supplied to the cavity at the suction side and flowing out of a film-cooling hole at the suction side of the air foil,
wherein the passage for cooling air supplied to the cavity at the pressure side and the passage for cooling air supplied to the cavity at the suction side are provided with pressure adjustment members, and the number of pressure adjustment members provided in the passage for cooling air at the pressure side is smaller than the number of pressure adjustment members provided in the passage for cooling air at the suction side.
2. The turbine blade according to claim 1 , wherein the pressure adjustment member provided in the passage for the cooling air supplied to the cavity at the pressure side and flowing out of the film-cooling hole at the pressure side of the air foil comprises an impingement plate provided downstream of cooling air flowing out of the cavity at the pressure side, and
wherein the pressure adjustment member provided in the passage for the cooling air flowing out of the film-cooling hole at the suction side of the air foil comprises an impingement plate provided upstream of cooling air flowing into the cavity at the suction side and an impingement plate provided downstream of cooling air flowing out of the cavity at the suction side.
3. A gas turbine comprising the turbine blade according to claim 1 .
4. The gas turbine according to claim 3 , wherein the diameter of impingement holes varies between stages.