Study On Bubble Identification In Gas-Liquid Tow-Phase Flow

Identification of gas-liquid tow-phase flow in gas-liquid mass transfer devices and computation of contact area between gas phase and liquid phase are the demand of gas-liquid mass transfer efficiency modeling. Gas-liquid mass transfer efficiency has the great significance to operation and management of gas-liquid mass transfer devices. As a complex, nonlinear and dynamic system, the measurement of two-phase flow parameters is very difficult. At present, how to identify the flow parameters rapidly by using modern information processing means has become one of the hotspots in the research fields of tow phase flow.This essay is with a view to measurement of gas area fraction, using wavelet transform and mathematical morphology to analysis gas-liquid tow-phase flow image. Some new image processing methods are proposed in this essay. Many experimental results show that those methods are efficient.Firstly, a new adaptive image enhancement approach based on the theory of wavelet is brought forward. In this approach, wavelet coefficients are enhanced by different strategies according to scale correlation. For the algorithm aims at minimizing the image noise while amplifying the image features, it is suitable to the low contrast image with noise obviously.After a survey to image segmentation is given, it is pointed out that two of the difficult problems in image segmentation using wavelet transformation are suppression of noise and selection of threshold value.