When fan and pump impellers rotate at high speeds, vortices and cavitation are generated, resulting in noise and vibration. To address this issue, it is essential to accurately understand the flow conditions in the wake of the impeller. However, measuring flow conditions such as vortices in a swirling flow through visualization experiments has proven to be extremely challenging. Additionally, the general method requires converting the flow inside the impeller to relative coordinates by subtracting the circumferential velocity from the filmed image when examining the flow as a relative flow. Therefore, we aim to develop a 3D swirling flow relative velocity distribution measurement system using two rotating object relative still recording devices for the purpose of three-dimensional measurement of vortices in the swirling flow downstream of an axial flow fan impeller. This report describes the method for correcting the distortion of stereo images and the results of PIV analysis based on the corrected stereo images.
Tahara et al. (Wed,) studied this question.