Dragging objects through powder 1

[insideman]

I am trying to find references to drag force for moving solid objects through a powder. The powder is a polishing medium, free flowing, density about 24 lb per cubic foot.

Can you help?

 

[handleman]

I doubt you're going to find value in any calculated value. Empirical is going to be your best bet.

 

[PeterCharles]

I suppose it's because I was trained long before you could go searching on the web and putting questions on discussion forums, but when faced with problems like this my answer is "how can I set up a test and measure the result". In that way I know what I did, how I interpreted the results and how much confidence I have in the results.

 

[dvd]

I agree with PChas. above. Too many people are willing to take the first answer that anyone will give them and run with it. Set up the experiment and take data. It is especially valuable if you are wrong about something. You can sit down with your bosses and explain what you did, instead of saying that some stranger told you what to do on the internet. Regardless of what you do, you should make sure that the boss knows your assumptions before you make parts.

 

[insideman]

Thanks to all. You seem to think I am some callow youth asking for homework help. I did a lot of work on this before asking. I am 80 years old.

 

[btrueblood]

insideman,

It's been years since I looked at it in the U of Wash. Engrg. Library, but did find a journal that is dedicated to powdered fluid dynamics; mostly concerned with powder/granular conveying...somewhere in that combination of terms (powder granular fluid conveying dynamics) is the journal title...I think. Hopefully, there are discussions in there of drag forces on fixed elements (valves, pipe elbows, struts) in a conveying stream, which should give you a means for estimating drag forces.

A quick google search yields the following:

Powder Technology
Journal of Fluid Mechanics
Physics of Fluids

as a partial list of journals touching on the topic.

Going a bit further, one can find the following scholarly article:

http://www.nd.edu/~granular/slowdrag.pdf

You may need to try and find the last reference in that paper.

 

[dvd]

My apologies for any slight. You deserve a salute for continuing to keep involved.

You might try posting your question on one of these forums:

http://www.bulk-online.com/Forum/index.php

http://www.powderandbulk.com/cgi-bin/yabb/YaBB.pl?board=general

 

[insideman]

Good stuff! Thanks much! Pat