Mechanical in-tank mixing involving viscous media is an essential operation in industrial sectors such as pharmaceuticals, chemicals and petroleum, among others. In such processes, the quality of the final product depends on the homogenization obtained, which is a consequence of the operating conditions. This topic has been studied using numerical and experimental methods.[1-3]In practice, mixing of viscous liquids in stirred tanks is often accomplished using reduced clearance impellers such as helical ribbons ( HR). Although open impellers are sometimes used for fluids of moderate viscosity (less than a few tens of Pa•s), macromixing with HR-type impellers has been well accepted even if the lower part of the mixing vessel is subject to parasitic flow phenomena such as segregation phenomena. and compartmentalized regions which lead to long mixing times due to low pumping capacity. Reports available in the literature studying HR mixing performance discuss the geometry of HR mixers as very diverse variables: single ribbon, double ribbon, impellers with or without internal screw fixed along the central shaft, even used in tanks cylindrical tanks with a flat bottom or in tanks with a rounded bottom.[4,5]. Beckner and Smith[6] and Brito et al.[7] reported the power consumed by HR stirring both Newtonian and non-Newtonian liquids. Delaplace et al.[8] provided a detailed description of the application of HR in industrial processes with emphasis on the effects of geometric parameters such as number of ribbons, pitch size (p), blade width (w) or the effects of clearance on the bottom wall on circulation and mixing times. The study of macroscopic parameters parameters for small mixing volumes (<75 L) have been the main subject of published reports, even for Newtonian or non-N flows...... middle of article... ...e on the mixing of Newtonian viscous flows for industrial purposes. Hence the aim of the present work is to develop a numerical investigation to describe the hydrodynamics generated by a standard helical ribbon wheel in a stirred tank in comparison with two redesigned HRs at the bottom. The analysis focuses on improving axial pumping in the lower part of the reservoir and discusses flow patterns, power consumption and several distributive mixing criteria such as pumping capacity, shear rate and l stretching efficiency. An originality of the present work lies in the Poincaré maps prepared to compare the mixing performances based on the monitoring of a single massless tracer during one hour of mixing. Such a long period represents a challenge for computer science studies. To our knowledge, this has never been done before for the characterization of HR wheels. .