Complex networks have established themselves in recent years as being particularly suitable and flexible for representing and modelling many complex natural and artificial systems.Oil-water two-phase flow is one of the most complex systems.In this paper,we use complex networks to study the inclined oil-water two-phase flow.Two different complex network construction methods are proposed to build two types of networks,i.e.the flow pattern complex network (FPCN) and fluid dynamic complex network (FDCN).Through detecting the community structure of FPCN by the community-detection algorithm based on K-means clustering,useful and interesting results are found which can be used for identifying three inclined oil-water flow patterns.To investigate the dynamic characteristics of the inclined oil-water two-phase flow,we construct 48 FDCNs under different flow conditions,and find that the power-law exponent and the network information entropy,which are sensitive to the flow pattern transition,can both characterize the nonlinear dynamics of the inclined oil-water two-phase flow.In this paper,from a new perspective,we not only introduce a complex network theory into the study of the oil-water two-phase flow but also indicate that the complex network may be a powerful tool for exploring nonlinear time series in practice.
Flow characteristics of both oil and water in a horizontal pipe are the basic information for the design of crude oil transportation and production profile logging.The flow characteristics are more complicated when oil or water carries sediment particles.In order to simulate the distribution of flow characteristic parameters of water-or oil-sediment mixture in a horizontal pipe,the governing equations and the boundary condition for the mixture phase of water-or oil-sediment were established by the mixture algebraic slip model (MASM) based on the Eulerian description method,and the numerical solution was obtained by the finite difference method and successive over relaxation (SOR).The simulation results indicated that the mainstream velocity moved downwards with increasing volume fraction of the particle phase and decreased with reducing pressure drop.The distributions of the volume fraction of the particle phase in the circular cross section were related to the mainstream velocity,and the volume fraction values increased downwards and sidewards with reducing mainstream velocity.Moreover the mainstream velocity of the oil-sediment mixture phase was larger than that of the water-sediment mixture phase.The mixture algebraic slip model could well simulate the flow characteristic parameters of the mixture phase with higher computing efficiency.
