Theoretical modelling of natural gas unsteady flow rate measurement using variable differential pressure method

Variable differential pressure flowmeters are very often used in many industries. Therefore, within the framework of this work, this method is adapted for measuring the flow and quantity of natural gas using the theory of similarity approaches. The article presents a simple method of obtaining analytical correlations for the natural gas flow rate measurement, and produces an equation for natural gas expansion factor. It also investigates the limits of applicability of the standard equation for the steady flow expansion factor. The results of an analysis of the errors in gas flow rate measurement, without being taken into account by the Strouhal number, in different pipe sections and flow transducers, have been presented.