The droplet size, size distribution, refractive index, and temperature can be measured simultaneously by the rainbow technique. In the present work, the rainbow scattering diagram for a spherical droplet in the second...The droplet size, size distribution, refractive index, and temperature can be measured simultaneously by the rainbow technique. In the present work, the rainbow scattering diagram for a spherical droplet in the secondary rainbow region is simulated by the use of the generalized Lorenz-Mie theory. For achieving high spatial resolution in denser droplet sprays, a focused Gaussian beam is used. For droplet characterization, different inversion algorithms are investigated, which includes trough-trough (<em>θ</em><sub>min1</sub> and <em>θ</em><sub>min2</sub>) method and inflection-inflection (<em>θ</em><sub>inf1</sub> and <em>θ</em><sub>inf2</sub>) method. For the trough-trough algorithm, the absolute error of the refractive index is between −6.4 × 10<sup>−4</sup> and 1.7 × 10<sup>−4</sup>, and the error of the droplet radius is only between −0.55% and 1.77%. For the inflection-inflection algorithm, the maximum absolute error of the inverted refractive index is less than −1.1 × 10<sup>−3</sup>. The error of the droplet radius is between −0.75% and 5.67%.展开更多
文摘The droplet size, size distribution, refractive index, and temperature can be measured simultaneously by the rainbow technique. In the present work, the rainbow scattering diagram for a spherical droplet in the secondary rainbow region is simulated by the use of the generalized Lorenz-Mie theory. For achieving high spatial resolution in denser droplet sprays, a focused Gaussian beam is used. For droplet characterization, different inversion algorithms are investigated, which includes trough-trough (<em>θ</em><sub>min1</sub> and <em>θ</em><sub>min2</sub>) method and inflection-inflection (<em>θ</em><sub>inf1</sub> and <em>θ</em><sub>inf2</sub>) method. For the trough-trough algorithm, the absolute error of the refractive index is between −6.4 × 10<sup>−4</sup> and 1.7 × 10<sup>−4</sup>, and the error of the droplet radius is only between −0.55% and 1.77%. For the inflection-inflection algorithm, the maximum absolute error of the inverted refractive index is less than −1.1 × 10<sup>−3</sup>. The error of the droplet radius is between −0.75% and 5.67%.
