COMPARISON OF MIXING POWER CHARACTERISTICS FOR CURVEDBLADE (NS-60), FLAT-BLADE AND HOLLOW-BLADE IMPELLERS

摘要

The paper presents the mixing power characteristics of a new type of a curved-blade impeller with 60 deg. angle blade, the Narcissus NS-60 based on the impeller version reported by KRAITSCHEV et al. Experiments in a conventional mixing tank geometry with ID 0.4 m are described. Both Newtonian and non-Newtonian cases are considered. Water, a 0.5% pseudoplastic xanthan gum solution and viscoelastic 2% carboxymethylcellulose and 1% polyacrylamide solutions were used. The impeller rotational speed varied between 1 and 15 rps at intervals of 1 rps, and gas flow rate varied between 0 and 2 vvm at intervals of 0.16 vvm. In parallel, Rushton flat-blade turbine (FB) and hollow-blade (HB) turbine were tested at similar conditions. The functions Po = f(Re) and Pg/Pu = f(Fl) corresponding to the three types of impellers were determined and compared. The data obtained for the FB and HB impellers are shown to be close to the figures reported in the literature.