Effects of intermittent flows on turbine gas meters accuracy

摘要

Axial turbine gas meters are well known and appreciated instruments for custody transfer metering, when used at suitable conditions (steady-flow). In anomalous flow conditions (no steady state conditions), with perturbations in the flow (i.e. pulsating flows or intermittent flows), the metrological performance of turbine meter can dramatically decady, inducing remarkable systematic errors. In particular, in the case of intermittent on/off flow (i.e. when the flow is abruptly shut off by means of a valve) the turbine wheel slows down after the flow has stopped and consequently a gas volume is measured which is always higher than that which has actually flown through the gas meter.