JPH09196378A - Tail pipe of gas turbine combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a secondary flow from being produced from a side wall of a tail pipe to a casing side and hence eliminate distorsion of gas temperature distribution at tail pipe outlet by disposing a rotor side of an axial position of a curvature center of a part of a turbine just before an inlet of the same having a specific shape with respect to the axial direction than a casing side on the upstream side. SOLUTION: High temperature combustion gas from a combustor flows into from a tail pipe inlet 101 and flows into a turbine from a tail pipe outlet 104. A rotor side curvature center 103 of a tail cylinder part having a shape just before the outlet 104 where it changes its direction from a direction toward backward inclined with respect to the axial direction to a direction directed substantially axially backwardly is located upstream by a distance (d) from a casing side curvature center 102. Accordingly, the part forms a suction duct to prevent a negative pressure region from being produced on the casing side of the tail pipe. Hereby, a secondary air flow from a side wall 106 of the tail cylinder to the casing side is prevented from being produced, and hence distorsion of gas temperature distribution at the tail pipe outlet 104 is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transition piece of a gas turbine combustor that allows combustion gas to flow from a combustor to a turbine.

[0002]

2. Description of the Related Art An example of a transition piece of a conventional gas turbine combustor is shown in FIG. The high temperature combustion gas from the combustor (not shown) flows in from the tail pipe inlet 101 and flows into the turbine from the tail pipe outlet 104, as shown by the white arrow. The portion immediately before the transition piece outlet 104 which is the turbine inlet of the transition piece has a shape that is inclined with respect to the axial direction and changes its direction from a rearward direction to a substantially axial rearward direction. Then, the center of curvature 202 of the casing side wall surface and the center of curvature 203 of the rotor side wall surface coincide with each other, and the center of curvature 20
2 and 203 are located closer to the casing than the side wall surface of the casing, and are formed with curved ducts. The cross section of the transition piece upstream of the curved duct is shown in FIG.
As shown in FIG. 2 (b), the cross section of the tail cylinder, which is circular and is located downstream of the curved duct, is fan-shaped as shown in FIG. 2 (c).

On the downstream side of the curved duct just before the turbine inlet of the transition piece of such a gas turbine combustor, a load region shown by parallel hatching in FIG. 2 occurs on the casing side, and a comparison is made near the side wall 106 of the transition piece. A secondary flow 205 occurs in which the extremely low temperature gas goes around to the casing side of the transition piece.

[0004]

In the conventional transition pipe of the gas turbine combustor described above, a secondary flow is generated downstream of the bent portion near the outlet portion and the relatively low temperature gas near the side wall is retained in the transition pipe. Since it goes around to the casing side, the low temperature region on the transition piece casing side expands, and the high temperature region comes near the side wall. As a result, the gas temperature distribution at the outlet of the gas turbine combustor is distorted and the wall temperature of the transition piece is also non-uniform.

The present invention is intended to provide a transition piece of a gas turbine combustor which can solve the above problems.

[0006]

The transition piece of the gas turbine combustor according to the present invention has a shape that is inclined with respect to the axial direction and changes from a rearward direction to a substantially axial rearward direction immediately before the turbine inlet. The axial position of the center of curvature of the portion is located on the upstream side on the rotor side rather than on the casing side.

Since the present invention has the above constitution,
The portion of the gas turbine combustor immediately before the turbine inlet has a shape that serves as a suction duct instead of a curved duct, and a negative pressure region does not occur on the casing side at the outlet of the transition piece. By this, 2 from the side wall of the transition piece to the casing side
The generation of the secondary flow is prevented, the gas temperature distribution at the outlet of the gas turbine combustor is not distorted, and the temperature of the transition piece wall is not uneven.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIG. Since the present embodiment is the same as the transition piece of the gas turbine combustor shown in FIG. 2 except for the points described below, the same parts in FIG. 1 as those in FIG. The description is omitted.

In other words, in the present embodiment, the transition piece is located immediately before the transition piece outlet 104 through which the combustion gas flows into the gas turbine and is inclined with respect to the axial direction, and extends rearward in the axial direction from the rearward direction. The curvature center 103 on the rotor side of the portion having the shape that changes the direction is arranged upstream of the curvature center 102 on the casing side by a distance d.

In the present embodiment, the high temperature combustion gas from the combustor (not shown) flows into the turbine from the tail pipe inlet 101 and flows into the turbine from the tail pipe outlet 104. Then, the rotor-side curvature center 103 of the portion of the transition piece that has a shape that is inclined immediately with respect to the axial direction and that is inclined rearward from the axial direction and changes its direction substantially axially rearward is set to the casing-side curvature center 103. Since it is positioned upstream of the distance 102 by a distance d, this portion serves as a suction duct, and a negative pressure region does not occur on the casing side of the transition piece. This prevents a negative pressure region from being generated on the casing side in the vicinity of the transition piece outlet 104, and a secondary flow from the side wall 106 of the transition piece to the casing side does not occur. Therefore, the gas temperature distribution at the tail tube outlet 104 is not distorted, and the tail tube wall temperature is not uneven.

[0011]

According to the present invention, the center of curvature of the portion immediately in front of the turbine having a shape that is inclined with respect to the axial direction of the gas turbine combustor transition piece and changes its direction from the rearward direction to the substantially axial rearward direction. Since the axial position of the rotor is arranged on the upstream side of the rotor side rather than the casing side, it is difficult for secondary flow to occur at the transition piece outlet portion, and distortion in the transition tube outlet gas temperature distribution is prevented. In addition, the wall temperature of the tail tube outlet can be made uniform.

[Brief description of drawings]

1 shows an embodiment of the present invention, FIG. 1 (a) is a longitudinal sectional view thereof, FIG. 1 (b) is a sectional view of a transition piece inlet, FIG.
(C) is a cross-sectional view of the transition piece outlet.

2 shows a transition piece of a conventional gas turbine combustor, and FIG.
2A is a vertical sectional view thereof, FIG. 2B is a sectional view of a transition piece inlet, and FIG. 2C is a sectional view of a transition piece outlet.

[Explanation of symbols]

 101 tail tube inlet 102 casing side curvature center 103 rotor side curvature center 104 tail tube outlet 106 side wall 202 casing side curvature center 203 rotor side curvature center 205 secondary flow

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyasu Sato 2-1-1 Niihama, Arai Town, Takasago City, Hyogo Prefecture Mitsubishi Heavy Industries, Ltd. Takasago Plant

Claims (1)

[Claims] 1. An axial position of a center of curvature of a portion immediately before a turbine inlet having a shape that is inclined with respect to the axial direction and changes its direction from a rearward direction to a substantially axial rearward direction from a casing side. A transition piece of a gas turbine combustor characterized in that the side is arranged on the upstream side.