Experimental Study on the Spray Characteristics of Streamlined Direct-Injection Atomizer

Abstract

This article investigates the atomization characteristics of a streamlined direct-injection atomizer, which finishes the atomization process by coupling the air swirl with the conventional direct injector. First, we used experimental methods to focus on controlling its structural parameters and the liquid-to-gas flow ratio. We used a phase Doppler interferometer to measure the Sauter mean diameter (SMD) of the droplets and used a high-speed camera to capture the atomization field images. The experimental results showed that, under all test conditions, the overall range of the SMD was from 84 to 100 μm. It was found that a higher liquid-to-gas flow ratio resulted in a smaller SMD, a larger distance between the liquid and air outlets led to a larger SMD, and an increase in the axial angle of the liquid jet led to a smaller SMD. We found the influence parameters of the atomization characteristics of the streamlined direct-injection atomizer based on the dimensional analysis, namely, π theorem. In addition, a calculation formula for the SMD was proposed, with multiple linear regression conducted on the sample data from experiment. Based on the findings of this study, the streamlined direct-injection atomizer can be used to dynamically control its spray characteristics according to the requirements of aviation engine combustion chambers.