Ducting arrangement for cooling a gas turbine structure

A ducting arrangement for a can annular gas turbine engine, comprising:

• a duct wall disposed between a combustor and a first row of turbine blades and comprising:
• an inner surface defining a hot gas path and an outer surface opposite the inner surface, the outer surface of the duct wall comprising raised geometric features;
• and
• a flow sleeve surrounding the outer surface of the duct wall and defining a cooling flow path there between;
• wherein the raised geometric features protrude into the cooling flow path;
• and
• wherein with respect to a hot gas path central axis, a diameter of an inner surface of the flow sleeve undulates in response to a change in a diameter of the outer surface of the duct wall along the hot gas path central axis, and with respect to the outer surface of the duct wall, the undulation is effective to impart an impingement vector to a direction of flow of a cooling fluid in the cooling flow path.

A ducting arrangement for a can annular gas turbine engine, comprising:

• a duct disposed between a combustor and a first row of turbine blades, defining a hot gas path therein, and comprising raised geometric features incorporated into an outer surface;
• and
• a flow sleeve defining a cooling flow path between an inner surface of the flow sleeve and the outer surface of the duct;
• wherein with respect to a central axis of the hot gas path, the inner surface of the flow sleeve deflects inwards when axially adjacent a landing disposed between adjacent raised geometric features, and the inner surface of the flow sleeve deflects outwards when axially adjacent the raised geometric features.