Flow visualization of simple pipe and channel flows obtained by MRI time-slip method

摘要

Herein, time-resolved magnetic resonance imaging, a noninvasive medical diagnostic imaging technique, was evaluated as a noncontact measurement tool for intuitively understanding fluid machineries. Simple pipe flows and channel flows are investigated by the 2D time-spatial labeling inversion pulse (2D time-SLIP) method, which can track a labeled water mass and visualize it using two-dimensional images. In this article, moving water masses of steady and pulsating pipe flows in a straight single pipe and a double cylindrical pipe (which are often seen in fluid machines and heat exchangers) are described. Then, abruptly contracting and expanding channels were tested and compared with particle image velocimetry (PIV) measurements or numerical simulations to evaluate their validity. In addition, as a feasibility test, a rotating water wheel and a fluidic diode with a strong swirling flow were tested to estimate this method's applicability to fluid machines. The results suggest that the time-SLIP method of tracking a labeled water mass is sufficiently accurate for use in simple fluid machinery under low Re number conditions.