End frame of a gas turbine transition duct and method of cooling thereof

摘要

A transition duct assembly (26, 28) for a gas turbine includes a transition duct (28) having opposite ends, one of the ends adapted to communicate with an inlet (14) to a first turbine stage; an impingement cooling sleeve surrounding the transition duct (28) with an annulus (44) therebetween, the impingement cooling sleeve (30) having a plurality of cooling apertures (46) formed therein; a transition duct end frame (26) connected to the one end of the transition duct, a forward edge of the impingement cooling sleeve (30) received in the end frame (26); the end frame (26) having a first plurality of cooling holes (36) axially beyond the forward edge of the impingement cooling sleeve (30), each cooling hole (36) communicating at the one end with space external of the impingement cooling sleeve; and a second plurality of cooling holes (42) in the end frame, each communicating at one end with the annulus (44), and at an opposite end with the first plurality of cooling holes (36). A method of cooling a transition duct end frame in a gas turbine includes the steps of a) directing cooling air into the end frame (26) from a region external of the transition duct (28) and the impingement cooling sleeve (30); and b) redirecting the cooling air from the end frame (26) into the annulus (44) between the transition duct (28) and the impingement cooling sleeve (30).