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-   -   Stirred tank torque validation - understanding the moment report (https://www.cfd-online.com/Forums/fluent/152923-stirred-tank-torque-validation-understanding-moment-report.html)

MCGI May 12, 2015 12:02

Stirred tank torque validation - understanding the moment report
 
Hi

I am modelling a simple stirred tank, and I have problems to understand qualitatively the moment report (even though I have read the fluent user guide, and the fluent theory guide).

My model is just an unbaffled tank (18cm diameter, 25 cm height), with a rushton turbine (6cm diameter) and I defined 2 phases: water from the bottom of the tank to 18cm height, and air from 18cm to the top. I used the rotating frame on the fluid zone, and I chose a rotating speed of 50rpm to ensure laminar regime.

When I print the moment report, I chose the moment centre at 0,0,0; since my tank is centred in this point. Then, I chose the moment axis 0,0,1; because I previously defined z as the rotation axis. I have read in several topics on this forum that the value that I am interested in to calculate the torque is the total net moment of all the walls that characterise the impeller; however, I am more interested in understanding the meaning of the values of the report, and why or why not the sum of all moments has to be equal to 0.

I hope that someone can help me with this issue,

Far July 21, 2015 18:06

this will give you the torque


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