Fuel injector and gas turbine

1. A fuel injector comprising: a fuel supply tube which has a tubular shape centered on an axis and into which a fuel gas is introduced from an upstream side in an axial direction in which the axis extends, a plurality of premix tubes which have a tubular shape extending in the axial direction and into which air is introduced from the upstream side; a support plate which supports a downstream side in the axial direction of the fuel supply tube and upstream end portions of the plurality of premix tubes, and oriented perpendicularly to said axis; a substrate which supports downstream end portions of the plurality of premix tubes, and oriented perpendicularly to said axis; an outer wall which is cylindrical, which connects the support plate to the substrate and forms a plenum inside together with the support plate and the substrate, a partition plate which partitions the plenum into a fuel plenum and a cooling air plenum disposed downstream of the fuel plenum, and oriented perpendicularly to said axis; a baffle, disposed downstream of the partition plate and upstream of the substrate, with at least a partially inclined portion radially outward on the downstream side with respect to said axis, and having holes through which premix tubes pass therein, and cooling holes are not formed in the al least partially inclined therein, and cooling holes are not formed in the at least partially inclined portion and a cooling air supply tube which is configured to supply cooling aft to the upstream cooling air plenum, wherein an end portion on the downstream side of the fuel supply tube opens in the fuel plenum; and at least one fuel introduction hole which penetrates each of the premix tubes inward and outward is formed at a portion positioned in the fuel plenum of the premix tube, wherein the baffle includes: a baffle body in which the cooling holes are formed and which is provided radially inside and attached to said outer wall with the axis as a center.

2. The fuel injector according to claim 1 , wherein at least some of the plurality of cooling holes are impingement holes.

3. The fuel injector according to claim 1 , further comprising a plurality of cooling air discharge holes which is formed in the substrate and configured to discharge the cooling air from the downstream cooling air plenum to the downstream side of the substrate.

4. The fuel injector according to claim 1 , wherein a cooling air introduction hole penetrating the premix tube inward and outward is formed at a portion positioned in the downstream cooling air plenum of the premix tube.

5. The fuel injector according to claim 1 , wherein the cooling air supply tube is disposed coaxially with the fuel supply tube on a radial inner side of the fuel supply tube.

6. A gas turbine comprising:

a compressor which is configured to generate compressed air in which air is compressed;

a combustor which includes the fuel injector according to claim 1 and mixes fuel with the compressed air to generate a combustion gas;

an air extraction part which is configured to extract the compressed air generated by the compressor;

a forced air-cooling compressor which is configured to further compress the extracted compressed air; and

a cooling air introduction part which introduces the cooling air generated by the forced air-cooling compressor into the fuel injector.

7. The gas turbine according to claim 6 , further comprising a cooler which is configured to cool the compressed air extracted by the air extraction part.

8. A gas turbine comprising:

a compressor which is configured to generate compressed air in which air is compressed;

a combustor which includes the fuel injector according to claim 2 and mixes fuel with the compressed air to generate a combustion gas;

an air extraction part which is configured to extract the compressed air generated by the compressor;

a forced air-cooling compressor which is configured to further compress the extracted compressed air; and

a cooling air introduction part which introduces the cooling air generated by the forced air-cooling compressor into the fuel injector.

9. A gas turbine comprising:

a compressor which is configured to generate compressed air in which air is compressed;

a combustor which includes the fuel injector according to claim 3 and mixes fuel with the compressed air to generate a combustion gas;

an air extraction part which is configured to extract the compressed air generated by the compressor;

a forced air-cooling compressor which is configured to further compress the extracted compressed air; and

a cooling air introduction part which introduces the cooling air generated by the forced air-cooling compressor into the fuel injector.

10. A gas turbine comprising:

a compressor which is configured to generate compressed air in which air is compressed;

a combustor which includes the fuel injector according to claim 4 and mixes fuel with the compressed air to generate a combustion gas;

an air extraction part which is configured to extract the compressed air generated by the compressor;

a forced air-cooling compressor which is configured to further compress the extracted compressed air; and

a cooling air introduction part which introduces the cooling air generated by the forced air-cooling compressor into the fuel injector.

11. A gas turbine comprising:

a compressor which is configured to generate compressed air in which air is compressed;

a combustor which includes the fuel injector according to claim 5 and mixes fuel with the compressed air to generate a combustion gas;

an air extraction part which is configured to extract the compressed air generated by the compressor;

a forced air-cooling compressor which is configured to further compress the extracted compressed air; and

a cooling air introduction part which introduces the cooling air generated by the forced air-cooling compressor into the fuel injector.