3D droplet sizing and 2D optical depth measurements in sprays using SLIPI based techniques

Abstract:
While imaging optically dense media such as atomizing sprays, the multiple light scattering induces image artifacts and blurring effects which limit visibility.
Therefore, extracting quantitative spray information such as droplet size and concentration from qualitative images becomes very challenging. However, multiple scattering effects can be efficiently addressed by means of the SLIPI (Structured Laser Illumination Planar Imaging) technique. Recently, using SLIPI in combination with LIF/Mie droplet sizing (ratio of the liquid Laser Induced Fluorescence (LIF) and Mie scattering signals), a mapping of absolute Sauter Mean Diameter (SMD or D32) could be extracted. It was observed that without SLIPI, reliable measurements of SMD could not be achieved. In another work, a 3D map of the droplet extinction-coefficient (µe) in an aerated spray was extracted using the SLIPI-scan technique. In this article, SLIPI-LIF/Mie droplet sizing is performed in combination with SLIPI-scan in order to construct a 3D representation of droplet SMD in the developed spray region and the corresponding optical depth in 2D.