A study of bubble dynamics in subcooled flow boiling using image processing technique

An experimental study of bubble dynamics in subcooled flow boiling was conducted using flow visualization and image processing methods. The flow pattern was recorded using a high speed cine camera and the resulting now images at any axial position were digitized in image analyzing system. A technique was developed to measure fundamental geometric parameters characterizing tile internal structure of bubble two-phase flow pattern such as: bubble size and shape, interfacial area, bubble growth or collapse position and velocity of the bubbles using image enhancement and segmentation techniques. The image was cleaned of noise using a set of image processing algorithms. These algorithms included background noise subtraction, contrast enhancement, median and smoothing filters and gray level thresholding and to be applied in that order for accurate evaluation and measurement of the fundamental parameters in two-phase, gas-liquid flows. (Original)