Wall slip determination for coarse food suspensions in tube flow at high temperatures

Abstract

An alternative method, developed based on variable particle concentration in conjunction with the wall slip correction method originally established by Mooney, was used to determine wall slip for model coarse food suspensions consisting of 1.5% CMC solution and green peas (15–30% v/v) in tube flow at high temperatures (85–135 °C). Within the wall shear stress range of 19.4–125 Pa, the slip coefficient varied from 3.09 × 10 −3 to 1.01 × 10 −2 m/Pa s and could be described well as a power function of wall shear stress. The rate of change in slip coefficient with wall shear stress decreased with the increase in the consistency coefficient of the carrier fluid. The opposite trend was observed with the increase in flow behavior index of the carrier fluid. It was also found that in general, contribution of the slip effect on the measured flow rate increased with the increase in particle concentration. The modified method presented here offers a simple alternative approach for computation of the wall slip effect of coarse food suspensions in continuous tube flow at high temperature, the scarce information of which is essential for further determination of their rheological properties.