N.D. Jin

Characterization of oil/water two-phase flow patterns based on nonlinear time series analysis

Abstract The flow patterns of oil/water two-phase flow in vertical upward pipes have been characterized by the analysis of fractal, chaos and Kolmogorov entropy based on the conductance time series fluctuating signals. It is shown that the fractal, chaotic dimensions and Kolmogorov entropy all have a good correlation with the total flow rate ( Q t ) and water cut ( K w ) for the flow conditions of 61%≤ K w ≤91%,10 m 3 /d≤ Q t ≤60 m 3 /d; for K w =51%, they show irregular sudden changes, which correspond to changes in the transitional flow pattern and is strongly supported by the characteristics of the complex power spectrum. It is concluded that the dimensions and the entropy are sensitive ‘indicators’ of flow pattern variations.

Flow pattern identification of oil/water two-phase flow based on kinematic wave theory

Abstract Based on the kinematic wave theory, the kinematic wave propagation velocity ( C k ) equation is established for oil/water two-phase flow in vertical upward pipes. The phase distribution coefficient C o and the bubble-size-related index N which reflect flow patterns have been characterized by using Zuber & Findlay Drift–Flux Model. The calculation of C k indicates that the instabilities of C k correspond to the transitional flow pattern of oil/water two-phase flow, which gives a new criterion that transitional flow pattern falls into the water hold-up ( Y w ) range of 0.2 Y w

Optimization of a conductance probe with vertical multi-electrode array for the measurement of oil-water two-phase flow

This paper proposes a conductance probe with vertical multiple electrode array (VMEA), which can be used in oil-in-water two-phase pipe flow to measure the water volume fraction and axial velocity. The electrodes are flush mounted axially on the inside wall of an insulating duct. Using finite element analysis method, the evaluating indicators of uniform degree spatial sensitivity and information volume were used to investigate the performance of the VMEA. The optimized VMEA has enhanced spatial sensitivity and capability of obtaining the distributed information from two-phase flow. Due to the significant difference of conductance between oil and water, the VMEA can also be used to measure gas-liquid and liquid-solid two-phase flow with conductive continuous phase. The evaluating indicators used in this paper can be used extensively to investigate other types of conductive probe.