Toward a Constant Coefficient of Discharge from a Nozzle via New Pressure Tap Locations

Two improvements were made to a long radius flow nozzle which could make these differential pressure head class elements more useful to the Navy. These were modifications to the locations of the downstream pressure taps resulting in improved discharge coefficients. The pipe Reynolds number ranged between 20,000 and 500,000 while testing the 0.4 Beta ratio nozzle. The first modification resulted in a nearly constant coefficient of about 0.985 over the whole range of Reynolds number. The second resulted in a constant coefficient of about 0.996 for pipe Reynolds numbers below 62,500 down to 20,000. The nearly constant discharge coefficient greatly facilitates the application of these elements to Naval shipboard piping--for example, as sensors for fuel oil metering in automatic combustion control systems. (Author)