Gas turbine combustor

1. A gas turbine combustor comprising:

a combustor liner as an inner duct in which a combustion chamber is formed;

a plurality of burners facing the combustion chamber;

a transition piece, as a tail duct, which is connected to the combustor liner;

a flow sleeve, as an outer duct, in which the combustor liner, the burners, and the transition piece are provided; and

an annular flow passage formed between the transition piece and the flow sleeve, between the combustor liner and the flow sleeve, and between the burners and the flow sleeve, through which compressed air, to be supplied to the burners for generating combustion gas, flows,

wherein a narrowing member is attached to an inner wall of the flow sleeve, the narrowing member protruding in the annular flow passage toward the combustor liner;

the combustor liner includes an annular protruding portion annularly formed on an outer wall of the combustor liner, the annular protruding portion protruding toward the flow sleeve;

the narrowing member includes an internal-diameter changing portion, an internal-diameter reducing portion, and a downstream internal-diameter changing portion;

the internal-diameter changing portion is diagonally connected to the flow sleeve to gradually approach the combustor liner as the internal-diameter changing portion extends in a flow direction of the compressed air;

the internal-diameter reducing portion is disposed at a downstream side of the internal-diameter changing portion in the flow direction of the compressed air, connected to the internal-diameter changing portion, and extending along the flow direction of the compressed air;

the downstream internal-diameter changing portion is disposed at a downstream side of the internal-diameter reducing portion in the flow direction of the compressed air, connected to the internal-diameter reducing portion, and diagonally connected to the flow sleeve to gradually recede away from the combustor liner as the downstream internal-diameter changing portion extends in the flow direction of the compressed air;

the internal-diameter changing portion is a first surface and a cross-section of the first surface taken along a plane crossing through the flow sleeve is a first straight line,

the internal-diameter reducing portion is a second surface and a cross-section of the second surface taken along the plane crossing through the flow sleeve is a second straight line, and

the annular protruding portion is located at a position on the outer wall of the combustor liner, the position facing a connection position between the flow sleeve and the internal-diameter changing portion or being at an upstream side of the position facing the connection position in the flow direction of the compressed air.

2. The gas turbine combustor according to claim 1 ,

wherein the internal-diameter changing portion has a curved connection portion with the flow sleeve and has a curved connection portion with the internal-diameter reducing portion.

3. The gas turbine combustor according to claim 1 ,

wherein the annular protruding portion has a curved surface at an upstream side in the flow direction of the compressed air.

4. The gas turbine combustor according to claim 1 ,

wherein the annular protruding portion has a curved surface at a downstream side in the flow direction of the compressed air.

5. The gas turbine combustor according to claim 1 ,

wherein the transition piece is connected to the combustor liner at an upstream side of the combustor liner in the flow direction of the compressed air,

wherein the annular protruding portion extends to a connection portion between the combustor liner and the transition piece.

6. The gas turbine combustor according to claim 1 ,

wherein the internal-diameter changing portion is connected to the flow sleeve at an angle of 7° or more.

7. The gas turbine combustor according to claim 1 ,

wherein, a position of the combustor liner facing a connection position between the internal-diameter changing portion and the internal-diameter reducing portion is a position D and a position of a top end portion of the annular protruding portion at a downstream side in the flow direction of the compressed air is a position E, the annular protruding portion has a protruding length toward the flow sleeve, the protruding length is a length such that an angle formed between a straight line connecting the position D with the position E and the combustor liner is equal to or smaller than an angle formed between the internal-diameter changing portion and the flow sleeve.

8. The gas turbine combustor according to claim 1 ,

wherein, the annular protruding portion has a protruding length h toward the flow sleeve, a position of a top end portion of the annular protruding portion at a downstream side in the flow direction of the compressed air is a position E, and an angle formed between a straight line connecting the position E with a reattachment point C of a downstream separation vortex generated by the annular protruding portion and the combustor liner is γ, a connection position between the internal-diameter changing portion and the internal-diameter reducing portion is located at a position downstream in the flow direction of the compressed air from a connection position between the annular protruding portion at the downstream side and the combustor liner by a distance of h/tan(γ) or longer.

9. The gas turbine combustor according to claim 1 ,

wherein the combustor liner further includes a plurality of turbulators formed on the outer wall of the combustor liner, the turbulators protruding toward the flow sleeve; and

the turbulators are located at a downstream side of the annular protruding portion in the flow direction of the compressed air, having a protruding length toward the flow sleeve smaller than a protruding length of the annular protruding portion toward the flow sleeve.

10. The gas turbine combustor according to claim 1 ,

wherein the flow sleeve further includes a plurality of longitudinal vortex generators formed on the inner wall of the flow sleeve, each of the longitudinal vortex generators protruding toward the combustor liner and generating a longitudinal vortex having a center axis of rotation in the flow direction of the compressed air; and

the longitudinal vortex generators are disposed at an upstream side of the internal-diameter changing portion and the annular protruding portion in the flow direction of the compressed air.

11. The gas turbine combustor according to claim 1 ,

wherein the downstream internal-diameter changing portion is a third surface and a cross-section of the third surface taken along the plane crossing through the flow sleeve is a third straight line.

12. The gas turbine combustor according to claim 1 ,

wherein the transition piece is connected to the combustor liner at an upstream side of the combustor liner in the flow direction of the compressed air, and

the transition piece is connected to the combustor liner to guide combustion gas away from the combustion chamber.