Gas turbine part comprising a near wall cooling arrangement

Abstract

A gas turbine combustor part of a gas turbine includes a wall, containing a plurality of near wall cooling channels extending essentially parallel to each other in a first direction within the wall in close vicinity to the hot side and being arranged in at least one row extending in a second direction. The near wall cooling channels are each provided at one end with an inlet for the supply of cooling air, and on the other end with an outlet for the discharge of cooling air. The inlets open into a common feeding channel for cooling air supply, and the outlets open into a common discharge channel for cooling air discharge. The feeding channel and the discharge channel extend in the second direction.

Claims

1. A combustor part of a gas turbine, comprising: a wall, which is subjected to high temperature gas on a hot side, the wall containing a plurality of near wall cooling channels extending essentially parallel to each other in a first direction within the wall in close vicinity to the hot side and being arranged in at least one row extending in a second direction essentially perpendicular to the first direction, the at least one row having a first end and a second end, and wherein the plurality of near wall cooling channels are each provided at one end with an inlet for a supply of cooling air, and on another end with an outlet for a discharge of cooling air, wherein the inlets of the plurality of near wall cooling channels open into a common feeding channel for cooling air supply, and the outlets of the plurality of the near wall cooling channels open into a common discharge channel for cooling air discharge, the common feeding channel and the common discharge channel extending in the second direction, the common feeding channel being open at the first end and closed at the second end, the first end configured to receive supplied cooling air and guide the supplied cooling air into the inlets of the plurality of near wall cooling channels, and the common discharge channel being closed at the first end and open at the second end, the second end configured to discharge cooling air from the outlets of the plurality of near wall cooling channels, and wherein the common feeding channel and the common discharge channel each have a cross section which is constant in the second direction, and wherein the plurality of near wall cooling channels include a first channel located at the first end and a plurality of second channels located between the first channel and the second end, and wherein each of the plurality of second channels between the first channel and the second end has a smaller cross section than a respective closest upstream neighboring near wall cooling channel, with respect to a flow of the supplied cooling air.

2. The gas turbine part according to claim 1, wherein each of the plurality of near wall cooling channels are arranged within the at least one row with an essentially constant inter-channel distance.

3. The gas turbine part according to claim 1, comprising: a plurality of rows of the plurality of near wall cooling channels, wherein the plurality of rows run parallel to each other in the second direction, each of the plurality of rows has a separate feeding channel and discharge channel with a common separation wall and respective outer channel walls, and wherein neighboring rows share an outer channel wall.

4. The gas turbine part according to claim 1, wherein each of the plurality of near wall cooling channels has a circular inlet and a circular outlet.

5. The gas turbine part according to claim 1, wherein the plurality of near wall cooling channels comprises at least three near wall cooling channels.

6. The gas turbine part according to claim 1, wherein the gas turbine part is a combustion liner.

7. A combustor liner of a gas turbine, comprising: a wall, which is subjected to high temperature gas on a hot side, the wall containing a plurality of near wall cooling channels extending essentially parallel to each other in a first direction within the wall in close vicinity to the hot side and being arranged in at least one row extending in a second direction essentially perpendicular to the first direction, the at least one row having a first end and a second end, and wherein the plurality of near wall cooling channels are each provided at one end with an inlet for a supply of cooling air, and on another end with an outlet for a discharge of cooling air, wherein the inlets of the plurality of near wall cooling channels open into a common feeding channel for cooling air supply, and the outlets of the plurality of the near wall cooling channels open into a common discharge channel for cooling air discharge, the common feeding channel and the common discharge channel extending in the second direction, the common feeding channel being open at the first end and closed at the second end, the first end configured to receive supplied cooling air and guide the supplied cooling air into the inlets of the plurality of near wall cooling channels, and the common discharge channel being closed at the first end and open at the second end, the second end configured to discharge cooling air from the outlets of the plurality of near wall cooling channels, and wherein the common feeding channel and the common discharge channel each have a cross section which is constant in the second direction, and wherein the plurality of near wall cooling channels include a first channel located at the first end and a plurality of second channels located between the first channel and the second end, and wherein each of the plurality of second channels between the first channel and the second end has a smaller cross section than a respective closest upstream neighboring near wall cooling channel, with respect to a flow of the supplied cooling air; and the at least one row comprising a plurality of rows, wherein the plurality of rows run parallel to each other in the second direction, each of the plurality of rows has a separate feeding channel and discharge channel with a common separation wall and respective outer channel walls, and wherein neighboring rows share an outer channel wall.

8. The combustion liner according to claim 7, wherein each of the plurality of near wall cooling channels are arranged within the at least one row with an essentially constant inter-channel distance.

9. The combustion liner according to claim 7, wherein each of the plurality of near wall cooling channels has a circular inlet and a circular outlet.

10. The combustion liner according to claim 7, wherein the plurality of near wall cooling channels comprises at least three near wall cooling channels.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention is now to be explained more closely by means of different embodiments and with reference to the attached drawings.

(2) FIG. 1 shows a conventional convective cooling design (a) and a near wall cooling design (b);

(3) FIG. 2 shows in general the feeding and discharging of near wall cooling channels, e.g. in a combustor liner application in a top view (a) and side view (b);

(4) FIG. 3 shows in a top view feeding and discharge channels with changing cross sections according to one embodiment of the invention (with oblique channel outer walls);

(5) FIG. 4 shows in a top view feeding and discharge channels with changing cross sections according to another embodiment of the invention (with oblique common separation wall);

(6) FIG. 5 shows in a top view a combustor liner application with plural adjacent rows of cooling channels and feeding and discharge channels with changing cross sections according to a further embodiment of the invention;

(7) FIG. 6 shows in a top view near-wall cooling channels with varying inlet and outlet hole diameter according to another embodiment of the invention; and

(8) FIG. 7 shows in a top view near-wall cooling channels with varying spacing in the direction of the row according to just another embodiment of the invention.

DETAILED DESCRIPTION

(9) Within the present invention and its equalizing means several ways to optimize and control the cooling performance are described.

(10) One way is to provide feeding and discharge channels with changing cross sections:

(11) As sketched in FIG. 3, the cross sections of the feeding and discharge channels 12 and 14, respectively, of a gas turbine part 10b can be adjusted along the cooling path. This is done by choosing the separation wall 13 of the two channels 12 and 14 to be strictly parallel to the extending longitudinal direction of the row of cooling channels 15, while the outer channel wall s 13a and 13b have an oblique orientation with respect to this direction such that the feeding channel narrows in this direction, while the discharge channel 14 widens respectively. In the example of FIG. 3, this narrowing and widening is linear with the distance in the longitudinal direction of the row.

(12) In this way, the pressure distribution can be influenced and therefore the mass flow entering the near wall cooling channels 15 can be controlled. Like in the case with constant cross sections (FIG. 2) several of these segments can be situated next to each other in order to cover large cooling surfaces (see FIG. 5).

(13) An equivalent variation in cross section can be achieved by the configuration shown in FIG. 4. Here, in gas turbine part 10c, the common separation wall 13 has an oblique orientation, while the outer channel walls 13a and 13b are oriented strictly parallel to the longitudinal direction of the row. This has the advantage that it allows directly a combustor liner application (combustor part 10d) by simply adding a plurality of such elements in parallel, as shown in FIG. 5.

(14) Another way to control and optimize the coolant mass flow through the individual near-wall cooling channels 15 is according to the combustor part 10e of FIG. 6 to vary the inlet and outlet diameters D of the near-wall cooling channels 15, while the cross sections of the feeding and discharge channels 12 and 14 may kept constant in the longitudinal direction. However, a combination of varying feeding and discharge channel cross section and varying diameter D of the cooling channels 15 is also possible.

(15) Despite controlling the mass flow rate through the individual near-wall cooling channels 15, it is also possible to optimize the spacing of the near-wall cooling channels 15 in longitudinal direction of the row (FIG. 7). At the feeding channel inlet of combustor part 10f, where due to the variation in static pressure, the coolant mass flow is lower, a denser arrangement of near-wall cooling channels 15 is applied to compensate the lower mass flow rates. However, a combination of varying feeding and discharge channel cross section and/or varying diameter D of the cooling channels 15 with a varying distribution density of the cooling channels in longitudinal direction is also possible.

(16) The characteristics and advantages of the invention are the following: Optimization of local cooling performance by adjusting the channel cross sections of the feeding and discharge channels as well as inlet and outlet diameters (D) of the cooling channels and/or their distribution density in longitudinal direction. Reduction of cooling air leads to reduction of necessary flame temperature and reduction of emissions. If less total cooling air is needed, the gas turbine efficiency can be increased.