Correlation of Power Consumption for Several Kinds of Mixing Impellers

Table 1

Correlation equations of power number for paddle (a), Rushton turbine (c) and anchor (f).

Unbaffled condition
𝑁𝑃0={[1.2𝜋^4𝛽^2]/[8𝑑^3/(𝐷^2𝐻)]}𝑓
𝑓=𝐶𝐿/Re𝐺+𝐶𝑡{[(𝐶𝑡𝑟/Re𝐺)+Re𝐺]^−1+(𝑓∽/𝐶𝑡)^1/𝑚}^𝑚
Re𝑑=𝑛𝑑^2𝜌/𝜇
Re𝐺={[𝜋𝜂ln(𝐷/𝑑)]/(4𝑑/𝛽𝐷)}Re𝑑
𝐶𝐿=0.215𝜂𝑛𝑝(𝑑/𝐻)[1−(𝑑/𝐷)^2]+1.83(𝑏sin𝜃/𝐻)(𝑛𝑝/2sin𝜃)^1/3
𝐶𝑡=[(1.96𝑋^1.19)^−7.8+(0.25)^−7.8]^−1/7.8
𝑚=[(0.71𝑋^0.373)^−7.8+(0.333)^−7.8]^−1/7.8
𝐶𝑡𝑟=23.8(𝑑/𝐷)^−3.24(𝑏sin𝜃/𝐷)^−1.18𝑋^−0.74
𝑓∽=0.0151(𝑑/𝐷)𝐶𝑡^0.308
𝑋=𝛾𝑛𝑝^0.7𝑏sin^1.6𝜃/𝐻
𝛽=2ln(𝐷/𝑑)/[(𝐷/𝑑)−(𝑑/𝐷)]
𝛾=[𝜂ln(𝐷/𝑑)/(𝛽𝐷/𝑑)^5]^1/3
𝜂=0.711{0.157+[𝑛𝑝ln(𝐷/𝑑)]^0.611}/{𝑛𝑝^0.52[1−(𝑑/𝐷)^2]}
Baffled condition
𝑁𝑃=[(1+𝑥^−3)^−1/3]𝑁𝑃max
𝑥=4.5(𝐵𝑤/𝐷)𝑛𝐵^0.8/𝑁^0.2𝑃max+𝑁𝑃0/𝑁𝑃max
Fully baffled condition
𝑁𝑃max=^10(𝑛𝑝0.7𝑏/𝑑)1.3(𝑛𝑝0.7𝑏/𝑑)≤0.548.3(𝑛𝑝^0.7𝑏/𝑑)0.54<(𝑛𝑝^0.7𝑏/𝑑)≤1.610(𝑛𝑝0.7𝑏/𝑑)0.61.6<(𝑛𝑝0.7𝑏/𝑑)