Discharging Through an Orifice Determines Steam-Water Enthalpy

Abstract

A wide range of steam-water mixtures was discharged to the atmosphere through a 10.7 mm diameter orifice which w a s sharp-edged with a minuscule throat pressure tapping. The ratio of throat pressure to up-steam pressure w a s found sensitive to dryness fraction over the whole range studied from 0.03 to 1.0. The technique (employing large orifices ) has the potential of identifying the unknown enthalpy of geothermal wells discharging large flows. Contrariwise, a nozzle (rounded entry orifice ) was found remarkably insensitive over nost of the dryness range and hence is useless for such determinations; however, it can be used to measure the flow-rate when enthalpy is known.