Effects of an acoustic atomizer upon liquid-fueled detonation initiations in a detonation tube

Abstract

The principle of a Hartmann-type acoustic nozzle is to generate ultrasonics to atomize the liquid fuel. Due to its outstanding performance on the atomization, the acoustic atomizer has been applied to internal combustion engine. Thus it possesses the potential to facilitate the liquid-fueled detonation initiations. In this paper, an acoustic atomizer was designed and established for a pulse detonation engine (PDE). The atomization characteristics and the flow pattern of the nozzle were analysed by a laser diffraction analyser and a high-speed camera. Multi-cycle detonation initiations experiments were conducted with the acoustic atomizer. The experimental results indicate that the performance of the nozzle was influenced by the air supply pressure, air-to-liquid fuel mass ratio and geometric parameters of the nozzle. The minimum Sauter mean diameter (SMD) measured was about 16 μm. The feasibility of the acoustic atomization scheme on cyclic detonation initiations was verified when the maximum operating frequency of the PDE reached 25 Hz. It suggests that the atomizer can effectively work under high-pressure condition in the detonation tube.