student profile: Mr Zipeng Chen


Thesis work

Thesis title: A smoothed particle dynamics based approach for modelling fluid-fracture interaction at meso-scale

Supervisors: Luming SHEN , Yixiang GAN

Thesis abstract:

Understanding the behaviour of multiphase flow through porous solid is important for a number of disciplines and applications, such as CO2 storage in brine aquifers, oil recovery in fractured reservoirs and water infusion in rock burst. Currently, dissipative particle dynamics (DPD), lattice boltzmann method (LBM) and smoothed particle hydrodynamics (SPH) were used to modelling this process. However, all these methods had few exact analytical expressions relating the fundamental fluid properties such as viscosity and surface tension. Therefore, the problems of particle clustering and instability would happen using the above methods. Besides, some phenomenon could not be modelled effectively, such as the surface tension of water and the interaction between immiscible liquid and solids. Although some researches tried to add artificial tension in their model, this method not only greatly changes the natural physical properties of the fluid, but also, highly increasing the computational cost. Then, some researchers tried another way to express surface tension. By considering inter-particle force that mimics the inter-atomic force in molecular dynamics, particle clustering and instability problems could be avoided. Besides, except the surface tension of water, the interactions between immiscible liquids and solid could also be modelled.

Nevertheless, successfully modelling the interaction between solid and liquid is not enough to demonstrate the mechanisms that govern two-phase flow in fractured porous media. Through observations and experiments, large deformation and fracture of solid induced by injected fluid are a common phenomenon in industrial application. In order to improve the understanding of this mechanism, the effect of deformation and fracture of solid induced by the fluid must be included in the studies. Moreover, a coupled dynamic solid boundary treatment is also necessary, to model the interaction between solid and liquid with complex interfaces and large density differences. However, studies considering these factors or combining them were few, due to their complexity and high computational cost. To analyse the coupled effect between fractured solid and fluid, some studies set the microscale fracture as a rigid body, so as to calculate the characteristics of two-phase flow in fractured media. Although this method is an improvement in modelling the flow process, it cannot simulate the generation of new fracture and the deformation of solid, which means that the property of porous media, such as porosity, is unchangeable, instead of dynamic.

Therefore, it is necessary to put forward a framework, which can simulate the interaction between multiphase flows and porous media. In addition, this framework can also model the dynamic process of deformation and fracture of solid induced by fluid, with relatively low computational cost.

Note: This profile is for a student at the University of Sydney. Views presented here are not necessarily those of the University.