Effect of rotation direction of helical-ribbon agitator on circulation of high viscous batch

Abstract

The article deals with the investigation of the homogenization process of high viscous liquid in a mixing tank. High viscous liquids are characterized by a high value of dynamics viscosity above value 10 Pa.s usually caused by Non- Newtonian behavior. There are lot of aspects that have a positive or negative effect on the homogenization efficiency, e.g. type of impellers, shape of vessel or spatial arrangement of the inserts in the vessel. The direction of the rotation of the proper impellers also affects the efficiency of the homogenization process. Correct high viscous liquid flow in mixing tank must be ensured by several specific types of impellers. The vertical direction of the liquid loop is recommended for homogenization process in cylindrical vessels. The simulations of the homogenization process of high viscous liquid in the cylindrical vessel have been performed. Two types of impellers were used. The axial pumping impellers were placed near the axis of vessel. The double-helical ribbon impeller ensured the liquid vertical movement near the wall. It has been found that the direction of the impeller rotation has a crucial effect on the homogenization effect, as expected. Simulations have been performed in ANSYS Fluent software. The liquid flow fields generated by clockwise (CW) and counter-clockwise (CCW) direction of the impeller’s rotation were investigated and compared.The article deals with the investigation of the homogenization process of high viscous liquid in a mixing tank. High viscous liquids are characterized by a high value of dynamics viscosity above value 10 Pa.s usually caused by Non- Newtonian behavior. There are lot of aspects that have a positive or negative effect on the homogenization efficiency, e.g. type of impellers, shape of vessel or spatial arrangement of the inserts in the vessel. The direction of the rotation of the proper impellers also affects the efficiency of the homogenization process. Correct high viscous liquid flow in mixing tank must be ensured by several specific types of impellers. The vertical direction of the liquid loop is recommended for homogenization process in cylindrical vessels. The simulations of the homogenization process of high viscous liquid in the cylindrical vessel have been performed. Two types of impellers were used. The axial pumping impellers were placed near the axis of vessel. The double-helical ribbon impeller e...