Numerical investigation of wet gas flow in Venturi meter

Study of the Venturi meter over-reading in wet gas is of considerable importance for the wet gas metering. Although the impacts of different parameters (e.g., liquid fraction, pressure and gas flow rate) on the over-reading have been widely investigated, the underlying mechanism on how these parameters act on the over-reading is still not fully understood. In this investigation, five types of turbulence models, including the standard kk-εε model, the RNG kk-εε model, the realizable kk-εε model, the standard kk-ωω model and the Reynolds stress model were examined. It was found that the standard kk-εε model was in better agreement with the experimental data. From the simulations, how and why the over-reading produced was explained. Then the liquid phase distributions and its impact on the velocity field and the pressure profiles were discussed. The results indicated that the liquid accumulated in the convergent section of the Venturi tube, where an annular liquid jet was formed. The static pressure in the throat declined along the throat, which made the static pressure in the throat unstable. To reduce their adverse effects on the over-reading of the wet gas flow, it was suggested that the classical Venturi tube should extend the length of the throat and decrease the convergent angle. This study gained a more comprehensive understanding of Venturi meter wet gas over-reading and provided a reference for the design of a wet gas Venturi meter prototype.

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► A liquid jet was formed in the Venturi meter and became obvious as the liquid fraction increased.
► The static pressure declined along the throat, which affected the OR of the Venturi meter.
► When used in a wet gas, the classical Venturi tube should extend the length of the throat and decrease the convergent angle.