×
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

Flash Relief of subcooled liquid at valve inlet

Flash Relief of subcooled liquid at valve inlet

Flash Relief of subcooled liquid at valve inlet

(OP)
Hi everybody,

I've some queries regarding relief valve calculations for subcooled liquid at inlet. My process involves water in subcooled state (170bar, 320deg.C). The relevant equation for omega-s parameter as per API 520 is 9*((rholiq_at inlet/rho9)-1). My query

1. what is the origin/ justification for '(' used above & also the above equation in general

2. I've some confusion in estimating rho9. API says it is the density evaluated at 90% of Psat corresponding to inlet temperature. This means about 102bar for my case. IT also says about isentropic/ isenthalpic flash. Should I take enthalpy at inlet (i.e. subcooled conditions) & carry out the flash to 102bar? in that case i'll get superheated vapor condition (i understand that rho9 is the liquid density). Please help.

RE: Flash Relief of subcooled liquid at valve inlet

for (flashing) subcooled liquids HNE could be preferable over HEM,
see this discussion at eng-tips forum

"http://www.eng-tips.com/viewthread.cfm?qid=332483"

you may compare results of HEM vs HNE ,
by the way Omega parameter gives a simplified solution of HEM method,
better to use the rigorous method (see Prode or similar tools).

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