Stirred tank system

1. Nov 10, 2011

db725

1. The problem statement, all variables and given/known data

The liquid in a production stirred tank system in which vortexing occurs has viscosity equal to 0.005 Pas and density equal to 900 kg m^3. A 1/5th scale laboratory model of the production unit is built to investigate the mixing performance. The liquid used in the laboratory model is chosen to ensure dynamic similarity on both Reynolds Number and Froude Number. Calculate the kinematic viscosity required for the laboratory liquid. Give units for your numerical answer.

2. Relevant equations
v : kinematic viscosity, v1 : laboratory kinematic viscosity, v2: production kinematic viscosity
μ : dynamic viscosity
ρ : density of the liquid
d : diameter of stirrer, d1: diameter of laboratory, d2: diameter of production

v=μ/ρ

v1/v2= (d1/d2)^2

3. The attempt at a solution

v1/(0.0005/900)= [(1/5)/(1)]^2 so v1= 72 000 (not sure about the units ??)

my attempt to the units are as below:

kg/m^3 x 1/(Pa.s) =kg/(mxN.s)

Can someone help? is this the right answer with the units included?

Thanks in advance for the help

Last edited: Nov 10, 2011