Determination of ASME Nozzle Flow Coefficients by Thrust Measurement

Abstract

This paper describes the recently developed thrust-measurement technique, a quasi-primary method, that is capable of calibrating very large ASME nozzles. The technique is an application of Newton’s law, force equals mass-flow rate times velocity. Application of boundary-layer theory allows the flow coefficient to be calculated from the thrust force, area, and pressure measurements. Test data indicate that the flow coefficient of ASME nozzles flowing compressible gas at high pressure ratio increases with throat diameter, independent of Reynolds number, and is about 1/2 percent lower than the coefficient for incompressible fluid at the same Reynolds number. This thrust-measurement technique has been used successfully to prove the thrust-measurement capability of many aircraft-jet nozzle test facilities.