Application of Hough transform for the identification of secondary flow patterns

This paper reports the application of Hough transform image processing technique to identify the existence of secondary flow patterns in a curved channel. When a fluid is forced through a passage with curvature, secondary flow appearing in spiral motion will superimpose on the main flow. Such phenomena are commonly found in many heat exchange equipment. While secondary flow promotes mixing of the fluids, thereby improving the heat exchange efficiency, limited attempts were made to improve the heat exchange process through the control of the secondary flow. In addition to the highly complex nature of the secondary heat transfer process, it is difficult to quantify or measure the extent of the secondary flow. Hence, much research and investigations have concentrated on the study of the exact mechanism and characteristics of the secondary flow. A novel approach using an image processing technique based on the Hough transform is used to locate and extent of the secondary vortices. The Hough transform, is used to capture the secondary flow system pattern and then it is used to reconstruct the boundary of the secondary flow patterns.