Chapter 46 - Local dynamic effect of mechanically agitated liquid on a radial baffle

Abstract

This chapter focuses on the measurement and analysis the distribution of the dynamic peripheral pressure affecting the radial baffle of standard pilot plant mixing equipment with four baffles at the cylindrical vessel wall with an axially located pitched blade impeller under turbulent regime of flow of agitated liquid. A radial baffle in a mechanically agitated tank prevents rotation of a liquid resulting in the origin of central vortex and also increases the efficiency of the mixing. An axially located pitched blade impeller in a cylindrical vessel with radial baffles exhibits the main force effects—axial and peripheral. The distribution of the peripheral (tangential) component of dynamic pressure affecting a radial baffle at the wall of a cylindrical pilot plant reactor with axially located rotary impeller under turbulent regime of flow of agitated liquid was determined experimentally The measurements are obtained under a turbulent regime of flow using the trailing target with balancing springs at seven axial distances above the flat bottom. The experiments are carried out for both investigated impellers at five levels of impeller speed and at three levels of agitated liquid viscosity. The results of the measurement are interpreted in dimensionless form. The dimensionless mean dynamic pressure affecting the baffle exhibits maximum value at the bottom and very low values in the upper half of the baffle for all three investigated impeller off-bottom clearances h/T = 0.2, 0.35, 0.5.