On fluctuation of the dynamic differential pressure signal of Venturi meter for wet gas metering

Abstract

Venturi meters are playing an increasingly important role in wet gas metering in natural gas and oil industries. Convincible measurement of the flowrate of wet gas requires two parameters, namely, the whole mass flowrate and its quality. It is commonly believed that the two parameters can be obtained if the Venturi meter is combined with another device of a different principle. However, this is not always the case. Owing to the complexity of the model for wet gas metering, the problem of multiple solutions may occur. Proceeding from a static model on the differential pressure (DP) signal of the Venturi meter, a dynamic model is presented that can provide an extra functional relation to resolve this problem without the need of adding a third device. This functional relation monotonously maps the relative fluctuation of the DP signal to the quality of the wet gas and simplifies the selection of the true solution. Experiments have been carried out within static pressure range of 0.3–0.8 MPa, gas flowrate range of 50–100 m 3/h and quality range of 0.06–0.412. Emphasis of the experiments has been on the demonstration of the validity of the static and dynamic models. Finally, appropriate discussions and conclusions are given.