SOUND ABSORBER OF DOUBLE-FLOW TURBOJET ENGINE Russian patent published in 2006 - IPC F02C7/24 F01N1/04 

FIELD: aircraft engines.

SUBSTANCE: proposed sound absorber of double-flow turbojet engine has ring duct walls with spaces outside the duct and sound-absorbing structures in spaces outside the duct in engine outer loop. Each sound-absorbing structure in space outside the duct is made in form of resonating chambers, mainly, Helmholtz chambers. Perforated wall arranged coaxially relative to outer and inner duct walls of channel is placed in spaces outside the duct of outer and inner duct walls of channel of engine outer loop. Ratio of areas of lining with noise-absorbing structures in spaces outside the duct of outer duct walls of channel of engine outer loop to areas of lining with noise-absorbing structures in spaces outside the duct of inner of said channel is where is acoustic parameter of channel of engine outer loop corresponding to logarithmic scale of 5 dB. Even number of perforated walls is arranged in spaces outside the duct of outer and/or inner duct walls of channel of engine outer loop. Each pair of perforated walls in space outside the duct forms slot resonating chamber arranged coaxially relative to outer and/or inner perforated duct walls of said channel. Area of each slot resonating chamber in spaces outside the duct of outer and/or inner walls of channel of engine outer loop is equal to area of linings with noise-absorbing structures in spaces outside the duct of said walls in said channel.

EFFECT: increased efficiency of noise absorption at minimization of losses of pressure and thrust owing to use of acoustically tuned slot resonating Helmholtz chambers.

5 cl, 5 dwg