NOISE EMISSION FROM OPEN TURBULENT PREMIXED FLAME

Abstract

Combustion noise is one of the main problems encountered in most of practical combustion systems. An experimental investigation has been carried out to study flame noise and the effect of mainstream air velocity and the equivalence ratio on it. Tests were carried out using an open turbulent premixed flame stabilized behind a conical bluff body (with 60° included angle and 0.42 blockage ratio). The fuel used was natural gas. Flame noise was measured by a condenser microphone coupled with audio frequency spectrometer. labcard, FFT analyzer and PC computer. Data analyses were carried out using a special software. The results showed that the flame noise spectrum, for any upstream velocity, is dependent on the equivalence ratio, and this dependence is as clear in rich limit as the lean one. It was found also that the sO'lnd pressure level is dependent not only on the equivalence ratio but also on the upstream mixture velocity.