Semiempirical prediction of Sauter mean diameter for pressure swirl atomizer based on instability theory
Based on the liquid atomization instability theory,a semiempirical model was established to predict the Sauter mean diameter(SMD)of pressure swirl atomizers,considering the Kelvin-Helmholtz(K-H)instability and Rayleigh-Taylor(R-T)instability generated by the interactions between air and liquid film.The experiments were also conducted using phase Doppler particle analyzer(PDPA)technique and digital off-axis holography with liquid temperature ranging from 240-300 K and liquid pressure ranging from 0.5-3 MPa.The results showed that:there were circumferential waves and axial waves on the surface of liquid sheet.With the decrease of liquid pressure and liquid temperature,the instability of liquid film was inhibited,which led to the increase of the SMD.Compared with the K-H instability,the effect of the liquid pressure on R-T instability was more significant;the effects of liquid physical properties,geometrical structures and operating conditions were included in the semiempirical correlation.The predictions showed good agreement with the experimental results,and the maximum uncertainty of the semiempirical correlation to predict the SMD was about±15％for the available experimental data,making it valuable for the prediction of atomization performance and the optimization of the structure of pressure swirl atomizers.
pressure swirl atomizerconical liquid sheetinstability theorySauter mean diameterprediction model
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