Calculating the Torque to mix a liquid

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    Liquid Torque
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To calculate the torque needed to mix liquid asphalt in a tank, the Reynolds number must first be determined using the formula Re = 10.7 * D^2 * N * specific gravity / viscosity. Given the tank's dimensions and the properties of the liquid, if the Reynolds number is 11.0 or less, torque can be calculated using the formula Torque [inch-pounds] = 6.8x10^-8 * viscosity * N * D^3. However, if the Reynolds number exceeds 1.0, a different approach may be necessary, as the initial formula may not apply. Understanding the flow regime is crucial for accurate torque calculations. Proper torque assessment ensures effective mixing of the liquid asphalt.
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There is a tank that is 12' 2" long and 65" in diameter that is capable of holding 2000 gallons of liquid asphalt, which is calculated to be 8lbs per gallon, viscosity is 8000CP. There are 8 paddles in this tank that they want to rotate around 25rpm. The diameter of the paddle arms is 60". How do I calculate the torque needed to "mix" this? Am I on the right path thinking that I need to calculate the Reynolds number by
Re = 10.7 * D^2 * N * specific gravity. / visc,
where N is the rpm, D is the diameter of the mixer. If the if the Reynolds number is 11.0 or less I can use
Torque [inch-pounds] = 6.8x10^-8 * visc * N * D^3 to get my required torque. But what if the Reynolds number is above 1.0?

Thanks for the help everyone.
 
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SevenToFive said:
There is a tank that is 12' 2" long and 65" in diameter that is capable of holding 2000 gallons of liquid asphalt, which is calculated to be 8lbs per gallon, viscosity is 8000CP. There are 8 paddles in this tank that they want to rotate around 25rpm. The diameter of the paddle arms is 60". How do I calculate the torque needed to "mix" this? Am I on the right path thinking that I need to calculate the Reynolds number by
Re = 10.7 * D^2 * N * specific gravity. / visc,
where N is the rpm, D is the diameter of the mixer. If the if the Reynolds number is 11.0 or less I can use
Torque [inch-pounds] = 6.8x10^-8 * visc * N * D^3 to get my required torque. But what if the Reynolds number is above 1.0?

Thanks for the help everyone.
 
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