Compressible Flow Examples

[JoeChem]

Greetings,

I have just put together a excel spreadshet to calculate compressible flows. I would like to check results against known solutions in piping systems. Is there a good reference work out there that has examples of compressible flows in piping systems? The best examples would be those that handle valves and fittings in addition to just a straight pipe.

Any help/insight will be greatly appreciated.

JoeChem

 

[Latexman]

It should also be applicable to gas/vapor flow problems that do not change density that much. I suggest doing the gas/vapor flow examples in Crane's TP 410, such as Example 4-10, 4-18, 4-20, 4-21, and 4-22.

Good luck,
Latexman

 

[TangoCleveland]

We use a commercial package, AFT Arrow, for compressible flow networks. Seems to be pretty accurate. I could send you outputs from their example problems, some of which are from Crane 410. Let me know if you're interested, and what types of systems you need results for.

Larry

 

[JoeChem]

OldSohioEngr,

I tried to get our company to purchase AFT Arrow. From what I hear it is the best compressible flow package on the market, especially for sonic choking. I could not get the funds so I had to put together something on my own.

We operate steam distillation units that employ live steam to recover essential oils from mint plants and pressed lime juice. The steam is fed through a piping network that terminates with a pipe distributor. The distributor itself is made up of multiple perforated pipes. I believe the whole distribution system is undersized and sonic choking occurs in more than one location within. I am looking for ways to perform calculations to prove it and to design a new system.

Anyway, the system is fairly complicated with lots of valves, elbows, tees, etc. Not easy to simulate. If you do have some appropriate examples of compressible steam flow I would sure like to take a look at them to see if my program is reasonably accutrate.

By the way can the AFT arrow program handle a perforated pipe distributor?

Thanks for the help.

JoeChem

 

[TangoCleveland]

Drop me a note at LEGmucs@grc.nasa.gov and I'll be able to send you the Arrow example of a steam distribution system.

Larry

 

[davefitz]

If the system is operating in a choked condition, one also needs to double check 2 limits:

a) the choked flow thru a valve should be checked using the ISA valve equations for compressible flow- one cannot simply use a fied equivalent fL/d value in this case

b) confirm location of any area minimums in the system, since actual choking might occur there and considerably affect the results.