Mixing

A.  Mild agitation results from superficial fluid velocities of 0.10-0.20 ft/s (0.03-0.06 m/s).  Intense agitation results from velocities of 0.70-1.0 ft/s (0.21-0.30 m/s).
B.  For baffled tanks, agitation intensity is measured by power input and impeller tip speeds:
		Power Requirements						Tip Velocity
		HP/1000 gal			kW/m3			ft/s			m/s
Blending		0,2	-	0,5	0,033	-	0,082	--------------------			--------------------
Homogeneous Reaction		0,5	-	1,5	0,082	-	0,247	7,5	-	10,0	2,3	-	3,1
Reaction w/ Heat Transfer		1,5	-	5,0	0,247	-	0,824	10,0	-	15,0	3,1	-	4,6
Liquid-Liquid Mixture		5,0			0,824			15,0	-	20,0	4,6	-	6,1
Liquid-Gas Mixture		5,0	-	10,0	0,824	-	1,647	15,0	-	20,0	4,6	-	6,1
Slurries		10,0			1,647			--------------------			--------------------
C.  Various geometries of an agitated tank relative to diameter (D) of the vessel include: Liquid Level = D Turbine Impeller Diameter = D/3 Impeller Level Above Bottom = D/3 Impeller Blade Width = D/15 Four Vertical Baffle Width = D/10
D.  For settling velocities around 0.03 ft/s, solids suspension can be accomplished with turbine or propeller impellers.  For settling velocities above 0.15 ft/s, intense propeller agitation is needed.
E.  Power to mix a fluid of gas and liquid can be 25-50% less than the power to mix the liquid alone.