GAS-TURBINE ENGINE AFTERBURNER Russian patent published in 1998 - IPC

FIELD: aircraft engine manufacture; afterburners. SUBSTANCE: two sections of fairing arc provided with perforations over definite protected length. As soon as vibratory combustion mode is attained, periodic fluctuations of pressure and gas velocity take place in afterburner. Acoustic vibrations of gas give rise to vibration of gas in perforations 5 and 6 of fairing 4. Perforated fairing 4 acts on gas vibrations in afterburner as resonance absorber (Helmholt resonator). Since acoustic field fairing 4 is similar to field in quarter-wave-length resonator; pressure fluctuations through perforation 5 of outlet section of fairing 4 occur at delay relative to pressure fluctuations of gas in combustion chamber at perforation 5. Perforation 6 is located at distance from end of fairing equal to 60-70 percent of its length, which makes it possible to tune fairing 4 as Helmholtz resonator, thus providing for effective dampening of acoustic vibrations within wide range of operation of afterburner. EFFECT: enhanced efficiency of dampening acoustic vibrations in wide range of operation of afterburner. 3 cl, 3 dwg