Combustor liner cooling thimbles and related method

A method of cooling a combustor liner of a gas turbine combustor, said combustor liner having a substantially circular cross-section, and a first flow sleeve surrounding said liner in substantially concentric relationship therewith creating a first flow annulus therebetween for feeding air to the gas turbine combustor, and wherein a transition piece is connected to said combustor liner, with the transition piece surrounded by a second flow sleeve, thereby creating a second flow first annulus in communication with said first flow first annulus;

• the method comprising:
• a) providing a plurality of axially spaced rows of cooling holes in said flow sleeve, each row extending circumferentially of said flow sleeve, a first of said rows adjacent said transition piece and said second flow sleeve;
• b) locating a plurality of cooling conduits in the cooling holes of at least said first of said rows, said cooling conduits extending radially inwardly towards, but not engaging, said combustor liner;
• c) supplying cooling air to said cooling holes such that said cooling conduits direct said cooling air against said combustor liner;
• and
• d) thereafter, directing said cooling air axially within said first flow annulus.

A gas turbine combustor assembly comprising a combustor liner and a transition piece connected to a downstream end of the combustor liner, the transition piece adapted to carry hot combustion gases in a first flow direction to a first stage of a gas turbine;

• a first flow sleeve surrounding the combustor liner with a first flow annulus radially therebetween;
• a second flow sleeve surrounding the transition piece with a second flow annulus radially therebetween, with said first annulus communicating directly with said second flow annulus;
• a plurality of rows of impingement cooling holes in said first flow sleeve, at least one of said plurality of rows located adjacent said transition piece at said downstream end of the combustor liner with a plurality of cooling conduits located in the impingement cooling holes of at least a first of said plurality of rows in said first flow sleeve and projecting toward said combustor liner;
• wherein, in use, cooling air flows through said cooling conduits to impinge on said combustor liner and mix with cooling air flowing through said first and second flow annuli in a second flow direction counter to said first flow direction.