Gas turbine arrangement
A gas turbine arrangement comprising: a passage, annular in cross section, for conveying combustion gases; located in the passage, turbine blading to be driven by the combustion gases; a diffuser, annular in form, for diffusing the combustion gases following their passage through the turbine blading; and a collector for collecting the combustion gases diffused by the diffuser, the collector comprising an annular main part, and, located at a position around the annular main part, a neck exit, in use of the gas turbine arrangement, combustion gases collected by the collector being conveyed around the annular main part of the collector in opposite senses so as to arrive at the neck exit of the collector travelling in opposed directions, wherein the neck exit of the collector includes a partition device whereby the opposed direction flows at the neck exit are kept substantially separate.
This application is the US National Stage of International Application No. PCT/EP2007/057595, filed Jul. 24, 2007 and claims the benefit thereof. The International Application claims the benefits of British application No. 0614687.2 filed Jul. 25, 2006, both of the applications are incorporated by reference herein in their entirety.
FIELD OF INVENTIONThe present invention relates to a gas turbine arrangement.
More particularly the present invention relates to a gas turbine arrangement comprising: a passage, annular in cross section, for conveying combustion gases; located in the passage, turbine blading to be driven by the combustion gases; a diffuser, annular in form, for diffusing the combustion gases following their passage through the turbine blading; and a collector for collecting the combustion gases diffused by the diffuser, the collector comprising an annular main part, and, located at a position around the annular main part, a neck exit, in use of the gas turbine arrangement, combustion gases collected by the collector being conveyed around the annular main part of the collector in opposite senses so as to arrive at the neck exit of the collector travelling in opposed directions.
BACKGROUND OF THE INVENTIONOne known such gas turbine arrangement is shown in
Referring to
In use of the gas turbine arrangement, combustion gases travel along passage 1, drive turbine blading 3, are diffused by diffuser 5, and are collected by collector 7. The combustion gases on leaving the diffuser 5 form within the collector 7 first and second opposite sense vortical flows 13a, 13b, see
The separating of the combustion gas flow off the shroud rim 15, and the meeting of the vortical flows 13a, 13b in the neck exit 11, result in the production of significant entropy in the flow. This is detrimental to the efficiency of the gas turbine arrangement.
SUMMARY OF INVENTIONAccording to the present invention there is provided a gas turbine arrangement comprising: a passage, annular in cross section, for conveying combustion gases; located in the passage, turbine blading to be driven by the combustion gases; a diffuser, annular in form, for diffusing the combustion gases following their passage through the turbine blading; and a collector for collecting the combustion gases diffused by the diffuser, the collector comprising an annular main part, and, located at a position around the annular main part, a neck exit, in use of the gas turbine arrangement, combustion gases collected by the collector being conveyed around the annular main part of the collector in opposite senses so as to arrive at the neck exit of the collector travelling in opposed directions, wherein the neck exit of the collector includes a partition device whereby the opposed direction flows at the neck exit are kept substantially separate.
In an arrangement according to the preceding paragraph, it is preferable that the turbine blading rotates about a centre line of the gas turbine arrangement, and the partition device runs parallel to the centre line, and extends radially from the centre line.
In an arrangement according to the preceding paragraph, it is preferable that the diffuser has a mouth whereby combustion gases leave the diffuser and enter the collector, the partition device comprises a first portion that extends over the mouth and a second portion that extends to one side of the mouth, and the second portion extends radially inward to a position closer to the centre line than the mouth.
In an arrangement according to the preceding paragraph, it is preferable that the side of the first portion that faces radially inwardly increases in distance from the centre line as the distance from the second portion increases.
In an arrangement according to any one of the preceding four paragraphs, it is preferable that the partition device comprises a flat plate.
In an arrangement according to any one of the preceding five paragraphs, it is preferable that the diffuser has a curved shroud rim whereat combustion gases leave the diffuser and enter the collector, the shroud rim has an extension operative to increase pressure recovery in the gas turbine arrangement, and the extension comprises a flat rim extension that is generally planar in form and forms a discontinuity with the curved shroud rim.
In an arrangement according to any one of the preceding five paragraphs but one, it is preferable that the diffuser has a curved shroud rim whereat combustion gases leave the diffuser and enter the collector, the shroud rim has an extension operative to increase pressure recovery in the gas turbine arrangement, and the extension comprises a spiral rim extension that continues or extends the curve of the curved shroud rim so as to form a spiral.
The invention will now be described, by way of example, with reference to the accompanying drawings, in which:
In
Referring to
Preventing meeting of the vortical flows 13a, 13b, reduces entropy production in the flow of combustion gases through the gas turbine arrangement, consequently improving the efficiency of the arrangement. The splitter plate 19 has the advantage that it is simple in design, and can be retrofitted to current gas turbine arrangement collectors.
In the above description, the partition device in the neck exit 11 of the collector 7 takes the form of a flat plate. It is to be realised that the partition device could take other forms that achieve the required separation of the opposed direction vortical flows 13a, 13b in the neck exit 11.
Claims
1-7. (canceled)
8. A gas turbine arrangement, comprising:
- an annular passage, configured to convey combustion gases;
- a plurality of turbine blading operatively rotatable about a centre line of the gas turbine and arranged in the passage and further operatively driven by the combustion gases;
- an annular diffuser configured and arranged to diffuse the combustion gases downstream of the turbine blading, the diffuser comprising a mouth where combustion gases leave the diffuser; and
- a collector comprising an annular main part, and a neck exit arranged at a position around the annular main part, the collector configured to collect the combustion gases diffused by the diffuser at the diffuser mouth such that the combustion gases collected by the collector are operatively conveyed around the annular main part of the collector in opposite senses so as to arrive at the neck exit of the collector travelling in opposed directions, wherein the neck exit of the collector comprises a partition device that runs parallel to the centre line and extends radially from the centre line and is configured to keep the opposed direction flows substantially separate at the neck exit, the partition device comprising a first portion that extends over the collector mouth, and a second portion that extends to one side of the mouth and radially inward to a position closer to the centre line than the mouth.
9. The arrangement according to claim 8, wherein a side of the first portion that faces radially inwardly increases in distance from the centre line as the distance from the second portion increases.
10. The arrangement according to claim 9, wherein the partition device comprises a flat plate.
11. The arrangement according to claim 10, wherein the diffuser comprises a curved shroud rim where combustion gases leave the diffuser and enter the collector, the shroud rim comprising an extension configured to operatively increase pressure recovery in the gas turbine arrangement and the extension comprises a flat rim extension that is essentially planar in form and forms a discontinuity with the curved shroud rim.
12. The arrangement according to claim 10, wherein the diffuser comprises a curved shroud rim where combustion gases leave the diffuser and enter the collector, the shroud rim comprising an extension configured to operatively increase pressure recovery in the gas turbine arrangement and the extension comprises a spiral rim extension that continues or extends the curve of the curved shroud rim so as to form a spiral.
Type: Application
Filed: Jul 24, 2007
Publication Date: Oct 1, 2009
Inventor: Paul Roach (Lincoln)
Application Number: 12/309,150
International Classification: F01D 25/24 (20060101);