Choke flow condition
Choke flow condition
(OP)
Could any one pl explain the concept of choke flow, and mach number in relation to flow across restriction orifices? What is it's significance in designing the RO? What are the equations which explain the Choke conditions? Any good links for understanding compressible fluid flow?





RE: Choke flow condition
Go to:
http://www.air-dispersion.com/usource.html
Milton Beychok has what is probably the best and most practical treatise on choked flow that you will ever read. His explanations are direct, down-to-earth and easily digested. He presents it in a manner commensurate with engineering applications and needs and you can readily detect the importance of the subject and the need to understand it.
You will not regret reading and downloading all the material he presents on that website.
Art Montemayor
Spring, TX
RE: Choke flow condition
That is an excellent description, but it has one short-fall, it assumes that the exhaust is always into atmospheric pressure. Every time the web page says "atmospheric" pressure I change it to "exhaust" pressure (in my mind) and it works. This is real important with chokes (both permanant and adjustable) and other throttled valves. 500 psia on the upstream of a globe valve and 272 psia downstream (with a k=1.3 gas) will be choked flow.
When I teach this class I tell folks that any time upstream pressure is more than about twice downstream pressure (in absolute terms) you will have choked flow. That fits very well with Baychock's 1.7-1.9 times (twice is easier to remember in a clutch and methane works out to 1.82 times).
David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
RE: Choke flow condition
RE: Choke flow condition
RE: Choke flow condition
For a given upstream pressure, the maximum gas or vapor flow rate that can be obtained through an orifice, would be the "choked flow" rate.
Have fun!
RE: Choke flow condition
these can be obtained be
Wellhead pressure- the separator pressure
Ther presure loss accross this sesiin in comparism with the other presure loss at each section of the system tell you the performance of the choke.