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pressure drop across jet or fitting

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wideopen231:
Spud,
  Wondering if you have fomula for figuring pressure drop across orfice like jet or fitting.Working on system  for nitrous enrichment(I know not your thing).I have it set up so its fed off of bypass at BV.It will have plenty of fuel available just need to figure pressure so I can work on getting regulator.Yes I know stand alone system just for nitrous would be easier,but involve sperate pump and basicall whole system just for it.Will not be using enough for all of that.

If you know how to best figure w/o bench which would be best.Let me know.

Spud Miller:

 The subject of a future video :)

 Never having flowed the orifice, the best you can do is get close.

 Formula (solved for pressure for ya):

 PSI = ((GPM / (CV * AREA ))²   *  SG)

 The "2" is supposed to be a "square" (smallish, upper two-thing)

 CV is the kicker. If you have the known, flowed value for GPM at any SG and any pressure, you can figure the CV for the orifice. Then you can change the formula around to use the CV and some new parameters and get the new pressure or flow. Since you presumably don't have a flow number to use to get your real CV, use 21 for an Enderle bypass pill and 23 for an Enderle nozzle jet. The CV differs based on the size and shape of the hole...also the individual characteristics of each hole...the surface finish, leading chamfer, exit edge, length of the orifice.
 
 Also, the above is what is used to figure the pressure on the leading side of an orifice to get the GPM through it of the fluid of known SG. You might have to do some other figuring to get "pressure drop" in your system.

 Spud




 

wideopen231:
Thanks .Not all of the way to answer but good amount closer and very good info.

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