I got 0.786scfh (density at 74.7 psia and 100 deg.F is 0.4322 lb/cu.ft and at std. conditions it is 0.0763 lb/cu.ft). What are your values? I think there may be mathematical errors due to unit conversion and rounding up in my calculation.
Believe it or not : Goldbach's conjecture says any even number can be written as a sum of two prime numbers. Postulated in 16th century, nobody could, so far, prove it nor disproove it.
My calculatios using the Lee Company software gives 0.0146 scfm (0.414 Std Liter per Min). The orifice is 0.004" (~0.1mm) meaning 47500 Lohms. At 60 psig the absolute pressure is 74.7 psia at 100F. This is the theoretical flow rate. The actual flow can be 80-90% of this depends on the type of orifice.
Quark, how do you get a density of 0.4322 lb/ft3? For air at 60 psig and 100F (14.7 psia atmospheric base pressure), I get 0.36 lb/ft3.
That still doesn't explain though why you are getting a lower flow rate since that higher fluid density 'should' make your flow rate higher. In any event, I'm pushing my spreadsheet, I should do a manual calc as a check.
Plus, since the Reynold's number is going to be low in the upstream piping (and the OP doesn't give the pipe ID), my estimate of the orifice coefficient is suspect.
A little interpolation of the values stated here. The Cd I considered was 0.72 and I did the calculation as per the formula given in the above link. Anyhow I will check it as per Crane's Technical Paper this night.
I have used the exact formula that we have used/developed for designing high pressure very fast (100hz) ON-OFF electro-pneumatic valves and servo actuators, and received the same flow rate 0.41 Std liter per minute. This agrees with 0.86 scfh from TD2K.
