Tube Rupture into Refrigerant

[Michengr]

Anyone have any suggestions as to the best way to calculate the amount of shell side refrigerant that is pushed into the relief valve during a tube rupture relief scenario in a heat exchanger? The tube side is gasoline and I've calculated the flowrate based on flow thru both ends of an orifice (crane 410). Flashing does not occur after the tube break or when the fluid is mixed in with refrigerant. I've also calculated the required area of my relief valve, but I would like to know how much of the shell side fluid would pass during relief, but no idea how to calculate this.

The properties are as follows:
Shell Side (Refrigerant): Design P = 150#, Design T = 250ºF
Operating P = 35#, Operating T = 40ºF
Tube Side (Gasoline) : Design P = 270#, Design T = 250ºF
Operating P = 250#

Tube Rupture Flowrate = 71 gpm (using 50% overpressure)

 

[roker]

hello,

see API 521 for this case (rupture of a tube), by the way in these days in order to avoid this scenario the ratio of design pressures should be 1.3 (in you case it is 1.8, as you can see it is connected to the test pressure which is 1.3 times the design pressure) it is also explained in API 521.

regards,
roker

 

[MikeClay]

If the gasoline flow is 71 gpm, then the initial refrigerent flow will also be 71 gpm at relief conditions. This flow will either be vapor or a mixture of vapor and liquid refregerent at 71 acutal gal per min (9.5 acfm). This case must also be relieved. I know of no simple way to do a mixture of gasoline and refrigerent and usually ingore that case.

--Mike--