Comparative Study of Microcomputer-Based Gas Flow Computers

Abstract

Abstract A laboratory investigation was undertaken to evaluate and compare the performance of various microprocessor-based gas flow meters. A total of 45 tests were performed with both steady- and unsteady-state flow regimes to simulate field conditions. In general, the differences in cumulative volume obtained with the seven types of metering systems studied were in the range of 2 to 7%, with the mode being between 3 and 4%. In particular, the study revealed that under unsteady-state conditions the turbine meters agreed reasonably well, i.e., less than 3% percent deviation in cumulative volume, with the orifice plate devices. Data sampling rates were examined and found to have a pronounced effect on unsteady-state flow measurements, also, bearing in mind the generally high cost of pressure sensing elements, instantaneous values of flowing and differential pressure across the orifice were affected with randomly generated errors in order to investigate the effect on cumulative flow, and thus quantify the degree of transducer accuracy necessary to measure flow under a given set of conditions.