Tomographic Techniques for Measuring Fluid Flow Properties

摘要

Experimental fluid velocity profiles can be readily obtained by using tomographic techniques. Combining measurements of a fluid velocity profile with a simultaneous pressure drop permits the evaluation of rheological properties. In order to control a process and to assure product quality, it is useful to monitor the Theological properties in-line or on-line. Two tomographic techniques, magnetic resonance imaging (MRI) and ultrasonic Doppler velocimetry (UDV), were used to obtain velocity profiles for a 65.7° Brix corn syrup solution and a 4.3° brix tomato juice. The UDV technique provided velocity profiles that compared well with the MRI method. For the corn syrup, the shear viscosity of 1.37 Pa·s (UDV) and 1.51 Pa·s (MRI) agreed well with the offline measurement of 1.57 Pa·s. The tomato juice was best characterized as a Bingham plastic fluid. The yield stress ranged from 4.44 Pa to 4.70 Pa, which matched well with the off-line value of 4.50 Pa. The strengths and limitations of both techniques are presented.