Abstract: In the background of low pressure condition, over reading mathematics models of Venturi tube on wet gas measurement is studied, both in theory and in experiment. Firstly, a theoretical model is deduced from the momentum equation; then, lots of experiment is done on three Venturi tubes which are different in size, the meters, with β values of 0.404 8, 0.55 and 0.70 have been tested in Tianjin University’s Low Pressure Wet Gas Test Facilities. The effect of pressure, slip ratio and liquid ratio to over reading of venture wet gas metering is analyzed, and a new half-experiential model of Venturi tube on wet gas measurement is put forward and proved in good precision; Finally, experiment analyzing shows that signal of the Venturi tube whose diameter ratio is 0.55 scatters least.

Key words: Over reading, Stratified flow model, Two-phase flow, Venturi tube, Wet gas measurement