Pitched Blade Turbine Efficiency at Particle Suspension

Mixing suspensions is a very important hydraulic operation. The pitched six-blade turbine is a widely-used axial-flow impeller. This paper deals with effect relative impeller size and particle content on theefficiency of a pitched six-blade turbine at particle suspension. Two pitched six-blade turbines were used in model measurements of just suspension impeller speed. The ratios of the vessel to agitator diameter <em>D/d</em> were 3 and 4.5. The measurements were carried out in a dish-bottomed vessel 300 mm in diameter. The just suspension impeller speeds were measured using an electrochemical method, and were checked visually. A 2.5 % NaCl water solution was used as the liquid phase, and glass particles with four equivalent diameters between 0.18 and 0.89 mmand volumetric concentration from 2.5 % to 40% were usedasthesolid phase. The criterion values <em>π_s=P_o√Fr'³(d/D)⁷</em> were calculated from the particle suspension and power consumption measurements. The dependencies of <em>π_s</em> on particle content <em>c_v</em> show that larger agitators are more efficient for higher particle content