SILENCER Russian patent published in 2001 - IPC

FIELD: mechanical engineering; aircraft manufacture; designing devices for reducing noise level of gas flow having subsonic exhaust velocity, noise of exhaust gases of shaft-turbine engine of helicopter, for example. SUBSTANCE: silencer includes ejector and diffuser with perforations and sound-absorbing coat. Ejector is widening and is provided with flow divider in form of blades mounted on its walls opposite each other at angle relative to gas flow; diffuser is curvilinear at curvature angle of α = 10-15^o deg. and curvature radii for convex wall R₁ = (3-4)d and for concave wall R₂ = (4-5)d, where d is diameter of nozzle exit section of engine; nozzle exit section has form of ellipse whose larger axis is located in plane of diffuser curvature; it is equal to 5 to 10 % of area of silencer walls. Sound-absorbing coat may be made in form of z- corrugations at varying height H₁ = (0,05-0,1)d over section L₁ = (2,5-3)d,, H₂ = (0,2-0,3)d over section L₂ = (3-4)d, and H₂ = (0,2-0,3)d over section L₃ = (4-5,5)d.. EFFECT: reduction of noise level by 2 to 9 dB. 2 cl, 5 dwg