关键词: 气液两相流, 气泡, 上升管, 相分布, 梯度提升决策树

Abstract:

The double-wavelength transmission method is a high precision method to detect the phase distribution parameters of multiphase flow. In order to improve the accuracy of phase distribution measurement, the gradient bosting decision tree (GBDT) algorithm was proposed in this paper. Optical simulation was used to simulate the propagation process of bubble light with wavelength of 445nm and 635nm in gas-liquid two-phase flow under different phase distribution. The light intensity distribution of detection plane was collected and the influence of bubble center location and bubble radius on the light intensity distribution curve under different phase distribution was analyzed. The measurement model was developed with GBDT, and the corresponding database between the characteristic parameters and the bubble phase distribution was established with the missing width and missing offset of light intensity as the characteristic parameters. A trained model was used to predict the phase distribution of bubbles. The mean square error of the measurement model was less than 0.0008mm, and the mean square error was reduced by 33.33%, which proved that the measurement model was more suitable for the measurement of the phase distribution. An experimental platform was built to predict the flow phase distribution parameters of vertically rising bubbles, and the movement trajectory of the central position of bubbles was tracked.

Key words: gas-liquid flow, bubble, riser, phase distribution, gradient bosting decision tree (GBDT)