The instrument uses single or stacked differential pressure meters such as orifice plates, nozzles, venturi tubes or V-Cones as well as temperature and pressure sensor inputs.
This natural gas flow computer calculates the flow according to generic differential pressure equations for the ISO 5167 or V-Cone meters. The flow calculations incorporate the conditions at which the flowmeter was calibrated and accurately account for thermal expansion effect.
The AGA-8 Detail Characterization Method is used to obtain accurate values of density and compressibility factors for the flow calculations.
The gas density and compressibility factor calculations are based on the AGA-8 equations. The calculations are valid for the region:
-130°C < t < 400°C P < 280MPa
-200°F < t < 760°F P < 40000psia
volume flow =Mflow/ρflow
corrected flow = Mflow/ρ ref
Heat flow = Mflow•Hm
Mflow = mass flow
ρflow = density at flow conditions
ρ ref = density at reference conditions
Hm = mass gross heating value