A neural network to correct mass flow errors caused by two-phase flow in a digital coriolis mass flowmeter

Abstract

Coriolis mass flow meters provide accurate measurement of single-phase flows, typically to 0.2%. However gas-liquid two-phase flow regimes may cause severe operating difficulties as well as measurement errors in these flow meters. As part of the Sensor Validation (SEVA) research at Oxford University a new fully digital coriolis transmitter has been developed which can operate with highly aerated fluids. This paper describes how a neural network has been used to correct the mass flow measurement for two-phase flow effects, based entirely on internally observed parameters, keeping errors to within 2%. The correction strategy has been successfully implemented on-line in the coriolis transmitter. As required by the SEVA philosophy, the quality of the corrected measurement is indicated by the on-line uncertainty provided with each measurement value.

Two-phase flow metering of heavy oil using a Coriolis mass flow meter: A case study

“…The resulting neural net models can be run online to apply corrections to the raw mass flow and density readings in the presence of two-phase flow. Examples of the types of parameters, and the neural net modelling applied, are described in [7]. As demonstrated in the following example, this approach has delivered effective error reduction.…”

“…Two sensors monitor the While the flow-tube is essentially a mechanical device with a few electrical transducers (sensors and drivers), the transmitter is an electronic and computational device which drives and monitors the flow-tube, and which calculates the measurement data. A long-term research programme between the University of Oxford and Invensys Foxboro has been developing alldigital transmitter technology [2][3][4] with various improvements including fast response time [5,6] and an ability to operate in two-phase flow [2,3,[7][8][9]. The transmitter architecture includes audio quality analog-to-digital convertors (ADCs) and digital-to-analog convertors (DACs), with typical performance characteristics of 24-bit samples delivered at 48 kHz.…”

From research to product using a common development platform

“…This reads the sensor data and uses it to synthesise the drive waveform, a function carried out in analogue hardware within the original commercial transmitter. Advanced sensor processing (Henry, 2001;Liu, Fuent, Henry, & Duta, 2001) is carried out at the processor level.…”

Mass flow measurement of two-phase carbon dioxide using coriolis flowmeters

“…In recent years, some researchers have attempted to use Coriolis flowmeters for two-phase or multiphase flow measurement. Coriolis flowmeters incorporating with a bubble-effect model, a neural network, a fuzzy inference system and additional meters such as an ultrasonic flowmeter were proposed for air-water twophase flow measurement [6][7][8][9][10][11][12][13]. However, gas-liquid twophase CO2 flow is more difficult to measure than air-water two-phase flow as the phase transition between liquid and gas may take place during the measurement.…”