Experimental Determination of the Discharge Coefficients for Critical Flow through an Axisymmetric Nozzle

Discharge coefficients for critical flow nozzles were determined experimentally for hydrogen, helsum, nitrogen, and argon over a Reynolds number range from 10 to 10. Above values of about 200, the measured coefficients are in excellent agreement with those predicted by a straightforward application of boundary-layer theory. The results suggest that in many cases experimental calibration of metering nozzles might be avoided.