Experimental and theoretical study of annular flow using a venturi with conductance sensors

Wet gas metering is becoming an increasingly important problem to the oil and gas industry.
The Venturi meter is a favoured device for the metering of the unprocessed wet natural gas
production flows. Various combinations of techniques have been employed in annular gas-liquid two phase flows to measure the flow parameters (e.g. liquid film thickness, gas volume fraction and the phase flow rates). One of the most useful techniques which has proven attractive for many multiphase flow applications is the electrical conductance technique.
This paper presents an advanced Conductance Venturi Meter which is capable of measuring
the gas volume fractions at the inlet and the throat of the Venturi. This model is based on the
measurement of the gas volume fractions at the inlet and the throat of the Venturi meter using a
conductance technique. We measure conductance using two ring electrodes flush with the inner
surface of the Venturi throat and two ring electrodes flush with the inner surface of the Venturi inlet. The basic operation of the electrical conductance technique in a multiphase flow is that the conductance of the mixture depends on the gas volume fraction in the water. An electronic circuit was built and calibrated to give a dc voltage output which is proportional to the conductance of the mixture which can then be related to the water film thickness in annular flow.