Evaluation of a Close Coupled Slotted Orifice, Electric Impedance, and Swirl Flow Meters for Multiphase Flow

Abstract

The feasibility of a multiphase flow meter utilizing closely coupled slotted orifice and swirl flow meters along with an impedance sensor is investigated. The slotted flow meter has been shown to exhibit well behaved response curves to two phase flow mixtures with the pressure difference monotonically increasing with mixture density and flow rate. It has been determined to have less than 1% uncertainty in determining the flow rate if the density of the fluid is known. Flow visualizations have shown that the slotted orifice is a very good mixing device as well producing a homogenous mixture for several pipe diameters downstream of the plate. This characteristic is utilized to provide a homogeneous mixture at the inlet to the swirl meter. This is possible since the slotted orifice is relatively insensitive to upstream and downstream flow disturbances. The swirl meter has been shown to indicate decreased flow rate as the mixture density increases which is opposite to the slotted orifice making the solution of the two meter outputs to obtain density and flow rate feasible. Additional instrumentation is included. Between the slotted orifice and swirl meter where the flow is homogenous a custom manufactured electrical impedance sensor is installed and monitored. This array of instrumentation will provide three independent measurements which are evaluated to determine which system of equations are robust enough to provide accurate density and flow rate measurement over a wide range of gas volume fractions using a very compact system.

Study of hysteresis effects and emulsion properties in watercut measurement using high speed multi-frequency impedance sensor

“…In the Turbomachinery Laboratory at Texas A&M University, the impedance measurement method was used for gas volume fraction measurement in the gas-liquid (air-water) mixture employing two impedance electrodes and a slotted orifice plate as the flow conditioner and homogenizer [22]. In the current study, a similar sensor but with higher frequencies was implemented to measure the watercut in oil-water emulsions in an agitated vessel.…”

Research on the characteristics of internal turbine sensor mounted on underwater high speed moving body

“…Shafer [1] and Thompson [2] systematically studied sensor characteristics of the traditional water flowmeter mechanics by analysis and experiments very early. Until now, the related research has never been stopped and mainly concentrate on the following aspects: Changes of the sensor characteristics under different fluid and application conditions, such as different viscous liquids [3] and multiphase fluid [4]. The measuring range widening [5] [6], or measuring something else more than flow rate by using the devices [7], were also under study.…”

Multiphase flow measurements using coupled slotted orifice plate and swirl flow meter

“…One of the methods is to measure the flow by making the homogeneous flow with equal phase velocities in a two-phase flow conditions. This method enables single phase flow metering devices to measure multiphase flows [6,7]. This approach eliminates flow separators and associated costs.…”