Calculating friction force

[mschro]

I have a feed screw that is conveying material and then forcing it into a discharge tube. The bulk density of the product is 15 lb/ft^3 when it enters the discharge tube and 50 lb/ft^3 when it exits. The discharge tube is made from 316 ss and is 10 feet long (20 inches in diameter). If I can determine approximately what the axial force that the feed screw can create against the product entering the tube, can the frictional force of the product against the tube walls be estimated?

 

[chicopee]

A dynamometer should do the trick.

 

[FACS]

Seems like the "frictional force" or friction coefficient is only part of the equation.

The viscosity of the material is going to add to the force required to push it through as well as ....
The diameter of the tubing
The length of the tubing
The flow rate
And the Rheological properties of the material.. Newtonian or non... etc.

So no, you can't isolate the friction by just using on force measurement. It's not all due to friction.

Charlie

http://www.facsco.com

 

[mschro]

Thanks FACS.

This 10' long tube that the product is passing thru attaches to a flange/nozzle. Our customer is supplying this nozzle and is concerned about the loads that it will be subjected to. The screw is creating a rotating load into the column of material that is compacting within the tube. I am trying to somewhat accurately predict what those loads will be. The product is of varying consistency, but I do know thru testing that we are achieving on average a 3.3 compaction ratio. Any additional thoughts/suggestions would be appreciated.