×
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

flow in pipes

flow in pipes

flow in pipes

(OP)
dear all
iam so much confused of how much could be a pipe diameter to permit a flow rate of 400 lit/min of slurry from one tank to another, the flow by gravity, and the level differnce betwee the 2 tank is 1 metre and the length of the pipe is 10 metre

RE: flow in pipes

Hello,

have you decided on the material you want to use?
is velocity important to you?
how did you lay out your piping?

your present data is not enough for sizing.

Faraz
Calgary

RE: flow in pipes

(OP)
dear frank
thank you very much...
i forgot to tell that the pipe is made of upvc,
and the velocity is not that important iam only concerning about flow and the slurry is cold

ahmed assem

RE: flow in pipes

If you draw a sketch of the two tanks, it will be clearer.  

The head for flow will depend on the level in the two tanks and the elevation differences between the two tanks.  With your slurry density, you can convert this to a psi differential.  Then, you just need to solve for what pipe diameter with this differential will give you a flow of 400 l/min over a 10' length (don't forget your entrance and exit losses).

Is this just to allow a minimum flow between the two tanks?  Do you have to control the flow?  What happens as the levels change, is that a concern?

With slurries, you should also check your velocity and make sure you aren't going to have settling issues (sorry, don't have much experience in this field).

If you don't have a copy, Crane's Technical paper 410 is a highly recommended reference.

RE: flow in pipes

Guys,

I'm having a similar question in another thread http://www.eng-tips.com/viewthread.cfm?qid=136432&page=1.

I'll use this particular thread by ahmed to illustrate how I view this sort of problem. Do correct me if I'm wrong.


In my view, he has given sufficient data to SIZE the piping.   I would list down as follows:

V, Volumetric flowrate = 400L/min thru gravity   

(Somehow he has determined that the slurry will flow at 400L/min thru gravity. I've used this assumption without further questioning the validity)

but V = pi/4*(D^2) v

where v = fluid linear velocity (typical)


From various sites and discussion, at the moment it appears that a "typical" fluid velocity is in the range of about 5ft/s or about 1.5 m/s. [ Can anyone confirm this unequivocally???? ]


Using v = 1.5 m/s

and V = 400L/min = 0.006667 m3/s

we thus get:  D = 75.2mm  diameter on the piping


i.e. choose standard DN80mm piping.



****************************************


Note:  I've NOT considered the losses in the pipe, pressure drop due to viscosity of the slurry, bends in the pipe, overall pipe length etc. As such, I realize my calc above is extremely simplified. But just wanted to verify the BASIS with you guys. Thanks.

---engineering your life---

RE: flow in pipes

This is what I got using the http://www.engineeringpage.com/engineering/line.html site.   I used "Sodium Chloride sol with solids" to represent Ahmed's slurry (rightly or wrongly). Apparently, the site calculates the typical (or max) velocity as 3m/s though.


*********************************************************

CALCULATION INPUT
Selection Criterium      Usual maximum velocity for  Sodium Chloride (Salt) solution with solids 3    m/s
Flow Data       Flowrate    0.006667    m3/s
Pipe data      ANSI B36.10, B36.19



------------------------------------------------------------CALCULATION RESULTS
Flowrate             0.0067 m3/s             105.6741 GPM (U.S.)
           24.0012 m3/h          847.5944 ft3/h
  
The smallest suitable Pipe Size is 2.5 inch
External Pipe Diameter               73.02 mm                  2.87 inch
Wall Thickness                 5.16 mm                    0.2 inch
Internal Pipe Diameter                 62.7 mm                  2.47 inch
Fluid velocity               2.159 m/s                7.084 ft/s
  
As the above is an unusual size a 3 inch pipe is recommended.   
External Pipe Diameter                 88.9 mm                    3.5 inch
Wall Thickness                 5.49 mm                  0.22 inch
Internal Pipe Diameter               77.92 mm                  3.07 inch
Fluid velocity               1.398 m/s                4.587 ft/s

Note:

The thickness used is the standard wall thickness, no check with respect to the maximum operating pressure was performed.
As this is an unusual size a 3 inch pipe with a diameter of 88.9 x wall thickness of 5.49 is recommended.


---engineering your life---

RE: flow in pipes

Slurry piping design needs more detail than has been given here. What is the solid loading, the particle and bulk density, flow characteristics, particle sizes etc etc? You need to get a good book and spend a few solid hours learning about this before you commit to a design.

As a starting point you can use the reference at http://www.cispi.org/handbook/chapter8.pdf
I give this reluctantly, because although this is a very good reference for what it is intended for (i.e. sewage piping) it may not be applicable to your case. And with the limited data you have given I cannot say whether or not it is applicable. The CISPI document shows that with a slope of 1 in 10 you could use a 3" pipe 3/4 full or a 4" pipe half full. In both cases you would have velocities of over 6 ft/sec (assuming water density) and this would certainly keep a sewage pipe clean.

Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com

RE: flow in pipes

(OP)
hi all

i thank you all for the contribution in solving my problem
and i think i have solved it now

but i would like to ask what else info should i give to you to be full detail??

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