Thermal control of gas turbine engine rings for active clearance control

A gas turbine engine thermal control apparatus includes at least one annular spray tube (60) having spray holes (1) oriented to impinge thermal control air (36) onto a fillet (104) between an outer casing (66) and a forward thermal control ring (84) and, in a more particular embodiment, into a center (106) of the fillet (104). The apparatus may include an annular segmented stator shroud (72) attached to the outer casing (66) and circumscribing radial outer blade tips (82) of turbine blades (34) of a turbine rotor (30). A thermal air distribution manifold (50) encircling a portion of the outer casing (66) includes an annular supply tube (54) connected in fluid supply relationship to plenums (56) of header assemblies (57). The annular spray tube (60) is connected to at least one of the plenums (56) and may be elongated radially inwardly and axially. Baffles (130) attached to radially outwardly facing surfaces (132) of the panels (58) may be contoured to form exhaust passages (126) having exhaust passage inlets and outlets (134, 138) between the baffles (130) and the panels (58).