Velocity Distribution of Helical Ribbon Impeller in Mixing of Polymeric Liquids in the Transition Region

Velocity profiles are helpful for the confident design of mixing tanks in the transition region. In this article, velocity profiles for helical ribbon impeller have been studied using laser Doppler anemometry for viscoelastic liquids with rheological properties typical of those found in polymer processes. Local tangential and radial velocities were measured at radial positions on a horizontal plane passing through the middle of the helical ribbon impeller. New correlation is suggested for dimensionless local tangential velocity profiles in the transition region, i.e. 70 I\lRe 6700. Experimental results show that the magnitudes of dimensionless radial velocities are much less than dimensionless mean tangential velocities such that no considerable radial flow could be detected.