Infrared radiation suppressor for gas turbine engine

An apparatus for suppressing infrared radiation emitted from hot metal parts at the aft end of a gas turbine engine and from the exhaust plume thereof during engine operation comprising;

• an ejector vane assembly for introducing cooling ambient air into the hot engine exhaust gases;
• means attaching said vane assembly to said engine to receive engine exhaust gases therethrough;
• and means receiving said engine exhaust gases and cooling air from said ejector vane assembly;
• said assembly comprising, a central tubular support having a central axis and a plurality of roughly V-shaped vanes arranged in equally angularly spaced relation about said tubular support with their apexes extending radially outwardly from said support and arranged substantially perpendicular to said central axis and the outside surfaces of said apexes facing toward said engine, said V-shaped vanes being adapted to receive engine exhaust gases thereagainst and separate said exhaust gases into a plurality of streams arranged in angularly spaced relation about said central axis, each of said V-shaped vanes having a pair of sides adjoining its apex, the outer end portions of said vanes being adapted to receive cooling ambient air therethrough by ejector action produced by said engine exhaust and said sides of said vanes having inner end portions which introduce cooling air into said tubular support, said vanes introducing cooling ambient air into the central portion of said engine exhaust gases as well as between said plurality of streams of exhaust gases to provide optimum mixing action within an axial length defined by the dimension of said assembly along said central axis.

An apparatus for suppressing infrared radiation emitted from hot metal parts at the aft end of a gas turbine engine and from the exhaust plume thereof during engine operation comprising:

• an ejector vane assembly for introducing cooling ambient air into the hot engine exhaust gases;
• means attaching said vane assembly to said engine to receive engine exhaust gases therethrough;
• and a dogleg duct receiving said engine exhaust gases and cooling air from said ejector vane assembly;
• said vane assembly and dogleg duct cooperating to provide visual blockage of said hot metal parts;
• said assembly comprising a central tubular support having a central axis and a plurality of roughly V-shaped vanes arranged in equally angularly spaced relation about said tubular support with their apexes arranged substantially perpendicular to said central axis and the outside surfaces of said apexes facing toward said engine, said V-shaped vanes being adapted to receive engine exhaust gases thereagainst and separate said exhaust gases into a plurality of streams arranged in angularly spaced relation about said central axis, said V-shaped vanes having outer end portions adapted to receive cooling ambient air therethrough by ejector action produced by said engine exhaust and said vanes having inner end portions which introduce cooling air into said tubular support, said vanes introducing cooling ambient air into the central portion of said engine exhaust gases as well as between said plurality of streams of exhaust gases to provide optimum mixing action within an axial length defined by the dimension of said assembly along said central axis;
• said dogleg duct comprising an inlet mixing section having a circular inlet arranged concentrically around said ejector vane assembly with an annular space therebetween and having a substantially rectangular outlet, said annular space being adapted to receive cooling ambient air therethrough also by ejector action during engine operation, said circular inlet and rectangular outlet having a smooth transition portion therebetween which provides efficient mixing of said ambient air with said exhaust gases, a curved acceleration section adjoining said inlet section, said acceleration section curving about an axis and having a substantially rectangular cross-sectional outline and a gradually decreasing cross-sectional area at each position therealong assuring acceleration and turning of fluid flowing therethrough in a nonturbulent manner, and a diffuser section adjoining said acceleration section and having a substantially rectangular outline at each position therealong, each of said rectangular outlines at each of said positions along said acceleration and diffuser sections having its longer dimension side arranged substantially parallel to said axis to thereby assure said visual blockage of said hot metal parts.