Experimental analysis of the behaviour of a Venturi meter submitted to an upstream air/oil annular liquid film

• Behaviour of a Venturi meter submitted to a oil/water/gas flow in the annular regime.
• Role of the inversion process.
• Measurement of the atomisation rate in the convergent section and influence of the water cut.
• Link between the atomisation rate and the DP over reading.

The aim of this work is to study the response of a Venturi meter submitted to an annular two phase flow where the liquid phase contains simultaneously water and oil. After a literature survey on the oil/water/gas flow in pipes, this paper presents the results of an experimental analysis performed at low pressure on a vertical downward pipe configuration. In a first step the structure of the liquid film is described from visual observations using high speed video records. Relationship between the two liquids inside of the film structure is enhanced. Inversion phenomena described in the literature are observed for given fraction of water in the liquid phase (known as the water cut). In a second step, the analysis of the atomisation of the liquid inside of the Venturi meter is presented. No preferential atomisation of one of the two liquid is observed. The results obtained clearly show the influence of the water cut on the atomisation rate and confirm the influence of the inversion phenomenon. They also indicate the link between the atomisation process and the deviation in the gas mass flow rate deduced from differential pressure measurements.