2D VELOCITY VECTOR PROFILE MEASUREMENT AND PHASE SEPARATION ON SWIRLING BUBBLY FLOW USING ULTRASOUND TECHNIQUE

Two-phase swirling bubbly flow is a complex phenomenon which occurs in several industries such as a nuclear reactor. Its characteristic is indispensably necessary to be investigated especially the multi-dimensional velocity distribution. This present paper describes the development of Ultrasonic Velocity Profiler (UVP) method which is a noninvasive measurement and needless of optical access, to obtain a two dimensional (2D) velocity distribution of the bubble and liquid phase in swirling bubbly flow simultaneously. The measurement result is represented in the form of the 2D velocity vector To achieve the target, the multiple transducers and developed signal processing have been applied to the UVP system to measure a 2D velocity vector affected by bubble and liquid separately. For confirming the ability of Developed-UVP, the experiment was conducted on a vertical pipe co-current flow apparatus. The UVP measurement was demonstrated non-intrusively and without the optical requirement. The measurement applicability of Developed-UVP was evaluated by comparing with Particle Image Velocimetry (PIV) method on liquid flow and bubbly flow. Then, it was applied to obtain the 2D velocity vector in swirling bubbly flow. The velocity vector of the bubble and liquid could be separated clearly. Also, velocity distribution in swirling motion which was interacted of both phases was investigated understandably by using this measurement technique.