A novel experimental technique for accurate mass flow rate measurement

A new technique has been developed and demonstrated which allows the mass flow rate of gas exiting an initially pressurized plenum to be determined to reasonably high accuracy without the need for calibrated flow meters.The technique is applicable to discharge processes in which the mass flow rate is controlled by a sonic orifice. Once the plenum is calibrated–using a method that is described–the technique allows mass flow rate out of the plenum to be determined from a single pressure measurement and an initial temperature measurement without the need for a traditional flow-metering device. Accuracy is comparable to conventional tertiary measurement techniques.The technique has application to a wide range of facilities in which gas is supplied from a pressurized plenum, and in which installation of a conventional device is either impossible or prohibitively costly. The technique has been used to measure the mass flow rate in the Turbine Test Facility at QinetiQ, Farnborough.