Newbie question: Regarding mixing
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The company has recently added a new mixing tank that requires stirring. The tank dimensions are φ1920X2200, and the medium is entirely a solution with low viscosity. I would like to ask whether it is necessary to have a double-layer structure for this mixer, and why? Do any sailors have any good suggestions regarding the length, width, and thickness of the blades? Thank you all.
You can refer to chemical process design manuals. If the purpose of stirring is dissolution, a three-blade propeller type can be considered, with the blade width being 1/3 of the diameter. If the task involves liquid-liquid dispersion, an open-turbine type stirrer with slightly higher shear capacity may be suitable; again, the blade width is approximately 1/3 of the diameter. In cases where the viscosity is low, a single-layer stirrer will suffice. The maximum loading height is H = D, and your height-to-diameter ratio is quite appropriate.
Based on the owner’s description, this should be a simple homogeneous liquid mixing process, and a single-layer impeller will suffice.
If the speed is not high, consider a frame-type or anchor-type one
The same task can be accomplished in different ways: a large-diameter impeller combined with an appropriate rotational speed can be used, and one layer is sufficient if the number of liquid circulation cycles meets the requirements. If the size of the manhole in the tank is too small, a double-layer impeller with a reduced diameter can be considered to facilitate installation. It entirely depends on the actual operating conditions on site; please be informed, OP.
Reply to 2# ymlin1983: Thank you. In the end, a single layer was used, with the blades made slightly wider.
Reply to 2# ymlin1983: Hello, is there a mixer that can also separate suitable ingredients? It is to separate solids by particle size in water, thank you!
Height 2200. It should be designed as a two-layer mixer. Formally, three-blade propeller-type mixing or axial-flow mixing can be considered
If solid particles are present, the design must be based on suspension, and in that case double-layer impellers should be used. If there are no solid particles, a single-layer impeller for this liquid level is sufficient; it is recommended to use A310.