Planar liquid volume fraction measurements in air-blast sprays using SLIPI technique with numerical corrections

摘要

A methodology to improve the accuracy of liquid volume fraction measurement in a dense spray is presented. A combination of experimental technique, structured laser illumination and planar imaging (SLIPI) and numerical corrections is used to overcome losses in conventional planar laser-induced fluorescence (PLIF) imaging. A quantitative distribution of liquid volume fraction in a plane is obtained using corrected SLIPI-PLIF signal and PDIA (particle/droplet imaging analysis) technique. The methodology is applied to air-blast sprays for GLRs (gas to liquid mass ratio) 1, 2.5 and 4. The effect of multiple scattering is significantly high in the conventional PLIF signal imaging. A hollow cone spray geometry is observed at a GLR of 1 using the improved imaging technique. An increase in GLR from 1 to 4 leads to uniform distribution of liquid in a spray plane. A significant contribution of multiple scattering (similar to 62%) is observed in the conventional PLIF signal at GLR 4 along the axis of the spray. The symmetry in the SLIPI-PLIF signal is restored using the numerical corrections. The liquid volume fraction measurements from SLIPI-PLIF technique are further improved with the numerical corrections.