Reversion scheme for droplet parameters with rainbow refractometry based on Debye theory

Abstract

Rainbow refractometry is a non-intrusive technology for determining the refractive index and diameter of droplet simultaneously. Most of the present schemes for the refractive index and diameter of droplet are based on empirical formulas with Airy theory. However, the anti-noise capability and the generality of the empirical method are weak. In the paper, an objective function was designed to quantify the deviation between the low frequency component of the captured rainbow and the simulated rainbow with Debye (p=2) theory. Further, a novel inversion scheme for single droplet based on Debye (p=2) theory and the objective function was proposed. Experiments were carried out to evaluate the performance of the scheme. Results indicate that the relative error of the radius is less than 8%, the absolute error of the refractive index is better than 5×10-4.