Characterisation of Vertical Upward Gas-Liquid Flow Using a Non-Intrusive Optical Infrared Sensor

The pursuit to improve accuracy, cost effectiveness and safety in the operation of multiphase flow metering sums up the motivation for this work. Non-intrusive optical infrared sensors (NIOIRS) of 880 nm and 1480 nm wavelengths have been applied in this work for the objective identification of flow regimes, determination of phase fractions and ultimately for the measurement of phase volumetric flowrates in an upward vertical gas liquid flow. The sensing method detects flow structures based on the disparity of optical properties of each fluid. Air and water were used as working fluids to create GLF in vertical test and main rig setups with 0.018 m x 1 m and 0.0273 m x 5 m test section respectively under varied fluid flow rate combinations (0- 1.0 m/s of water and 0 - 13 m/s of air). Notable contributions were made in this work. These include (i) a derivation of a flow regime dependent phase fraction model, which accounts for interfacial scattering, hence improves phase fraction measurement (ii) A novel application of supervised learning methods to improve objective flow regime identification for a GLF (iii) Application of a modified calibration model to measure actual liquid velocities and flow rates In the absence of priori superficial velocities and slip ratio information (iv) a scheme to convert the NIOIRS into a GLF meter.