×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

How to determine aerator CFM

How to determine aerator CFM

How to determine aerator CFM

(OP)
I have a need to create an aeration tube in the bottom of a large storage tank. I plan on using 2" PVC pipe with a series of holes. I will construct a hexagonal shape with the PVC and place it in the bottom of the tank. I want to use an air compressor with a plate rating of 140CFM to aerate the liquid, at about 7PSI. My question is, is there any calculation I can use to determine:
1. Number and size of holes
2. Ensure the pressure is sufficient around the entire hexagon
3. Determine if 2" is the correct PVC pipe size to use?

Thanks,

RE: How to determine aerator CFM

What's in the storage tank?  If its water, you need to take the water height in the tank x 0.43 psi/ft, so with 7 psi, if the water is over 16 ft high, your air won't go out of the pipe at all. It might be better if you feed the ring from at least 2 or even 4 places with piping from the compressor, otherwise most of the air might be lost in the first 1/4 of the ring.

Look for the air flow tables at www.engineeringtoolbox.com
That will get you close enough for pipe sizing, because actually your air will not be arriving at the end of the pipe. Its all gone by then, which is why I think its better to keep the lengths short by feeding from multiple points.  In fact I would think it would be better to forget a ring and feed 4 "T" assemablies from the center of the tank (the bottom of that "T").  If you feed the ring from one end, it will be hard to get uniform air distribution around such a long ring.

"We have a leadership style that is too directive and doesn't listen sufficiently well. The top of the organisation doesn't listen sufficiently to what the bottom is saying."  Tony Hayward CEO BP
"Being GREEN isn't easy." Kermitfrog http://www.youtube.com/watch?v=hpiIWMWWVco

http://virtualpipeline.spaces.liv

RE: How to determine aerator CFM

Some more advice, from the "been there, done that" school of fluid mechanics.  Don't put the holes on the "top" of your headers, put them on the bottom.  That way, the air will displace the water out of your headers, and you have some chance of getting uniform distribution.  The other way, you have fairly chaotic startup conditions, with two-phase or slug flow occurring in most of the manifold, possibly continuing on "forever", as the water in the ends of the manifold never clears.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources