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[bertrand]

Dear All,
I am in front of something completely new.
According to DEP the tube rupture shall be evaluated in a Spiral Heat Exchanger (type: Alfa Laval for exemple).
DEP 80451011 October 2008:
Paragraph 4.2.1.7
Internal failure of spiral exchangers shall be evaluated on a case-by-case basis.

More restricting, in our project this case shall be considered if the exchanger high side design pressure is greater than 130 % of the design pressure of the low side, and not 150% as mentioned in the DEP.
In the same specification it is specified that for plate or printed exchangers the relief shall be evaluated by assuming a 1.5mm wide cracking along the length.

Here attached a Typical layout of a spiral heat exhcanger showing hot and cold channel.

The same problem is solved on a routine basis using the attached excel sheet for a round orifice. The complication in this case is that the orifice is not a round hole, but a crack.

Several cases can be expected
Case1:
HP=Steam
LP=Liquid

Case2:
LP=Steam
HP=Liquid

Case3:
LP=Liquid
HP=Liquid

I guess the case 1 could be the most difficult to describe, but if you have some clue to solve the others cases it is welcome.
Do you have any idea about what kind of equation I can use to solve the problem?

Regards
Bertrand - Process Engineer

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