Estimation of the Just Suspension Speed in Solid-Liquid Agitated Vessels With Various Impellers

Abstract

The current study proposes a new model equation that takes into account the effects of impeller Reynolds number, particle Reynolds number, and particle concentration on the just suspension state. This model equation can explain the exponent of correlation equation of Zwietering, which was difficult with previous model equations. Additionally, the validity of correlation equation of Zwietering was experimentally demonstrated. Aida and Shono proposed a correlation equation for the geometrical constant S of Zwietering for four general-purpose impellers: the flat paddle, the disk turbine, the pitched paddle, and the marine propeller. Using this correlation equation, the calculated S values for the A310, HE-3, Maxflo W impeller, retreat curve impeller, concave disk turbine, HS604, and Twinstir were compared to the literature values and found to be in good agreement with them. Thus, it is evident that the correlation equation of Aida and Shono can be used to estimate the values of S not only for the four general-purpose impellers but also for various other impellers.

Keywords

• Agitated Vessel
• Solid-Liquid Mixing
• Just Suspension Speed
• Zwietering’s Geometrical Constant
• Impeller Geometry