[nadirsha]

Dear All,

If you have flow rate, sp gravity, Kin. Viscosity, pipe roughness, Pipe length, losses and Elevation change, can we find out size of the pipe.

Do we consider the flow laminar while sizing?

What velosity can be assumed for chemicals?

Best Regards

nadir

[Art Montemayor]

nadir:

The answer to your questions are:

1. Yes, you can determine the appropriate (or optimum) size of a pipe if you know the fluid’s low rate, its absolute viscosity, the absolute pipe roughness, fitting and other losses, and elevation changes. But you also need to know the fluid’s density or specific gravity.
2. You decide whether you want laminar or turbulent flow. You control the type of flow with the Reynolds Number.
3. The velocity will depend on the type and quality of fluid you are transporting. Normally, I employ 5-7 ft/sec for water and other similar liquids; I use 100 to 125 ft/sec for air and similar gases. The velocity is related to the fluid’s pressure drop, so I normally fix a maximum, acceptable pressure drop and accept the resulting velocity if it is within the normal range I would expect. If not, then I increase the pipe size and reduce the pressure drop and the velocity.

The above questions are very basic and have been discussed and answered countless times in these Forums in the past. Try to do research and read up on prior posts by using our "Search" function. Obtain and study a copy of Crane’s Technical paper #410 or obtain a copy of the Cameron Hydraulic Data Book and study that. There are many more books and articles to read and study. Try to ask specific questions with detailed, specific basic data. Repeating generalized responses consumes a lot of time and effort and transfers very little important information.

Why did you post this fluid flow question in the Tank Blanketing & Venting Forum? Can I move this post to the Industrial Professional Forum since it is a general type of question?

[proinwv]

Nadir, I agree with Art, especially where he says:

The above questions are very basic and have been discussed and answered countless times in these Forums in the past. Try to do research and read up on prior posts by using our "Search" function. Obtain and study a copy of Crane’s Technical paper #410 or obtain a copy of the Cameron Hydraulic Data Book and study that. There are many more books and articles to read and study. Try to ask specific questions with detailed, specific basic data. Repeating generalized responses consumes a lot of time and effort and transfers very little important information.

Why did you post this fluid flow question in the Tank Blanketing & Venting Forum? Can I move this post to the Industrial Professional Forum since it is a general type of question?

This was posted in the incorrect forum and you will not take advantage of the knowledge available here if you mis-post.

I especially recommend the Crane paper and they are available for sale on the internet. Just do a search on the full title. The Cameron book is handy but may be difficult to find.

I wonder what your experience and background is to ask such a question. Most ChE or ME's would be familiar with this topic.

[nadirsha]

Thanks a lot for the informations.

Sorry, i am new, can any one to move this to appropriate?

Best Regards,

Nadir

[nadirsha]

Can any one explain the velocity to be considered for a chemical corrossion inhibitor or demulsifier etc??

What is the minimum Reynolds number whre the flow transmitters can work accurately, i got a calculation having rey. number of 150, and they are not recommending the differential pressure type flow transmitter for such a low flow, are they correct??

Best Regards

Nadir

[engware]

Hi there:

Check out the eFunda web site at: http://www.efunda.com where one can use free online calculators and see what the pressure loss is for given fluid velocities and properties -- pipe sizing can be done as well.

Thanks,

Gordan