The effect of second order refraction on optical bubble sizing in multiphase flows

In multiphase flow research and many industrial applications it is importan t to determine the bubble size and velocity. To achieve this, one of approa ches is to utilize laser phase-Doppler anemometry. However, it was found th at the second order refraction has great impact on PDA sizing method when t he relative refractive index of media is less than one. In this paper, the problem of second order refraction is investigated and a model of phase-siz e correlation to eliminate the measurement errors is introduced for bubble sizing. As a result, the model relaxes the assumption of single scattering mechanism in conventional phase-Doppler anemometry. The results of simulati ons based on this new model by using Generalized Lorenz Mie Theory (GLMT) a re compared with those based on the conventional method. An optimization me thod for accurately sizing air-bubble in water has been suggested.