Improvement of combustion efficiency and reduction of NOx emission by external oscillation of reactants in an oil burner

The important requirement for the development of burners is the achievement of low emissions, particularly NOx, while maintaining high combustion efficiency. In this works an externally oscillated oil burner was developed which provides both high-efficiency combustion and low NOx emission simultaneously. To investigate combustion characteristics and NOx emission, parametric studies were carried out about oscillation frequency, forcing amplitude, and air velocity. Optimum combustion was achieved at frequency of 1,900 Hz, amplitude of 3 V-pp, and air velocity of 6.8 m/s. The NOx and CO emissions were reduced by 47% and 22%, respectively. In particular, the mechanism responsible for the inherently low NOx emission levels from an externally oscillated oil burner has been shown to be a short residence time at high temperature caused by rapid mixing with cooler residual gases.