Smart questions
Smart answers
Smart people
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Member Login




Remember Me
Forgot Password?
Join Us!

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips now!
  • 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!

Join Eng-Tips
*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.
Jobs from Indeed

Link To This Forum!

Partner Button
Add Stickiness To Your Site By Linking To This Professionally Managed Technical Forum.
Just copy and paste the
code below into your site.

bouk (Petroleum) (OP)
4 Nov 11 12:03
Hi everyone,

I have an existing control valve and I wish to check it is adequate for some different flowrates. When I model the valve in Hysys with a pressure drop, I notice that the liquid phase upstream of the valve becomes liquid with a bit of vapour downstream. Do I need to use any different equations to the liquid control valve sizing equation to determine my CV for these new given flowrates?

Has anyone a template I could use for checking?

Regards
casflo (Mechanical)
7 Nov 11 13:03
You must use different equations to obtain the maximum allowable  pressure drop in the valve to calculate the valve Cv.
For example if the fluid is water that at the valve inlet begins to flash, the maximum valve pressure drop used to calculate the valve Cv is: 0.04FL**2Ps(1+7(Ps/3206)**0.5
FL is the valve recovery factor. It depends of the valve type and manufacturer. A normal value could be 0.9
Ps is the saturation pressure in psia and the pressure drop is in psi.
If the valve inlet pressure is P1 and is grater than Ps, add to the former valve pressure drop the value (P1-Ps)FL**2 and if P1 is less than Ps you must subtruct (Ps-P1)FL**2
Regards.
casflo
 

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!

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close