Simulation and static measurement of the gas volume fraction in a separated flow model using a Conductance Multiphase Venturi Meter (CMVM)

The assumption of equal mixture densities at the inlet and the throat of the Venturi is only valid in a homogenous flow. This assumption is no longer valid for a separated flow and therefore, the measurement of the gas volume fraction at the throat must be introduced. This paper presents an advanced Conductance Multiphase Venturi Meter (CMVM) which is capable of measuring the gas volume fraction at the throat of the CMVM. In water continuous multiphase flow, the electrical conductance technique has proven attractive for many industrial applications. In gas-water two phase flow the electric conductance technique can be used to extract the gas volume fraction. We measure conductance using two ring electrodes flush with the inner surface of the Venturi throat. Different nylon rods with different diameters were inserted at the center of the throat to simulate the gas volume fraction at the throat. Experimental static tests for a vertical and a horizontal Venturi meter were performed in which the water film thickness and the gas volume fraction (i.e. the volume occupied by a non-conducting rod) were measured. In this paper, the experimental results were also compared with those obtained from COMSOL finite element software. It was inferred from this comparison that the error was less than 1.95 %.