The Simulation Of Fluid Flow Based On Dissipative Particle Dynamics

With the continuous development of science and technology, the computer simulationtechnology has become an important way of scientific research. The computer simulation cansave manpower and material resources, reduce the experiment cycle, test the feasibility of theprediction results. It can also realize the simulation under the ineligible experiment condition,such as high temperature plasma and nuclear reactor simulations. Nowadays, the computersimulation has been applied to almost all of the sciences, such as material science, life science,objects, meteorology and architecture, engineering, etc. This paper focuses on dissipativeparticle dynamics simulation of fluid flow. This paper studies the flow of poiseuille flowbased on dissipative particle dynamics simulation and simulates multiphase fluid flow byimproved dissipative particle dynamics.This paper firstly introduces the topic background, and then introduces the the researchstatus at home and abroad of dissipative particle dynamics (DPD). Then it introduces thetheoretical basis of the dissipative particle dynamics including theory model, the numericalintegration method, and real fluid mapping, boundary conditions, DPD method improvementand application, dimensionless, DPD procedures, etc. With theoretical basis, we can studywell of the DPD system.Secondly this paper introduces the model of the fluid flow, as well as the poiseuilleflow. And derived the formula and parameters needed in DPD simulation, and get theoreticalanalysis of Poiseuille flow solution. We analyse the modify for the dissipative force weightfunction expression and the influence of s on schmidt number and viscosity dissipation ofthe system. Finally we establish a detailed research plan to simulate poiseuille flow betweentwo infinite long plate. Compare the analysis results between s=1/2and s=2poiseuilleflow, include the final fluid flow speed, system temperature, density and other properties.Analysis shows that when s=1/2the final flow speed closer to the analytical solution of thefluid. Finally we apply dissipative particle dynamics (DPD) to research the two phase flow inthe Y channel, given the simulation result of the third chapter，we have adopted theexpression of the weight function of dissipative force with index s=1/2, at the same time weuse cubic smooth function to conform the conservative force weight function of particles, andapply this model in simulating the two phase flow in the Y channel, and then use smoothfunction to structure the conservative force weight function of particles, and apply it tosimulate the two phase flow in the Y channel. Comparing the simulation results with cubicsmooth function and with biquadrate smooth function, we find using biquadrate smoothfunction the effect long-distance attract short-distance repulsion is more obvious. On the basisof the conservative force weight function with biquadrate smooth function, we adopt theanisotropic potential energy as a potential energy between particles, and apply the new modelto simulate the two phase flow in Y channel, analysis the relation and the difference betweenthese two situations.