Abstract: A transition duct (40) for a gas turbine engine (10) incorporating a combination of cooling structures that provide active cooling in selected regions of the duct while avoiding cooling of highly stressed regions of the duct. In one embodiment, a panel (74) formed as part of the transition duct includes some subsurface cooling holes (92) that extend under a central portion of a stiffening rib (90) attached to the panel and some subsurface cooling holes (94) that have a truncated length so as to avoid extending under a rib end (45). Effusion cooling holes (88) used to cool a side subpanel (48) of the panel may have a distribution that reduces to zero approaching a double bend region (48) of the panel. An upstream subpanel (76) of the panel may be actively cooled only when the panel is located on an extrados of the transition duct.

Abstract: A transition duct (40) for a gas turbine engine (10) incorporating a combination of cooling structures that provide active cooling in selected regions of the duct while avoiding cooling of highly stressed regions of the duct. In one embodiment, a panel (74) formed as part of the transition duct includes some subsurface cooling holes (92) that extend under a central portion of a stiffening rib (90) attached to the panel and some subsurface cooling holes (94) that have a truncated length so as to avoid extending under a rib end (45). Effusion cooling holes (88) used to cool a side subpanel (48) of the panel may have a distribution that reduces to zero approaching a double bend region (48) of the panel. An upstream subpanel (76) of the panel may be actively cooled only when the panel is located on an extrados of the transition duct.