How to model a line with a leak in it.

Solution ID: 110946

Product(s): Aspen HYSYS

Version(s):V8.8, V8.6, V8.4, V8.3, V8.2, V8.1, V8.0, V7.3, V7.2, V7.1, V7.0, 2006.5, 2004.1, 2004, 3.4, 3.2 Build 5029, 3.1 Build 4815

Primary subject: Utilities, Depressuring - Dynamic

Last Modified: 12-Aug-2005

Attached files (filesize):  

LINE-LEAK1.HSC (1211 k): Sample Case

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Applicable Version(s)

Up to and including 3.1

Problem Statement

How do I do a depressurization model of a vessel or pipe line that has a leak in it?

Solution

To model a leak, you will want to use the General (Choked Flow) valve equation, and specify the Av coefficient, which is the orifice area (leak area). When using SI units, the Av is in m^2 and for Field units, Av is in ft^2.

Do not forget to use an appropriate Isentropic Efficiency value: for liquid filled systems, use 40% - 70%. For gas filled systems, use 87%-98%. If you have a two-phase system, you can use a value in between the two ranges, e.g 80%).

Note: In the attached sample case, the example was created using HYSYS 3.1, using the "dynamic depressuring" utility, which is the new version of the original "depressuring" utility. When using this sample case in HYSYS 2004, you will be asked if you want to update to use the new template. You can select Yes or No. If you select Yes, you will be switched over to use the new template from HYSYS 2004.

KeyWords

Depressuring, leak, depressurization