Coarse Projective Integration Multi-scale Simulation Methodology Research And Its Application

Fine scale simulation method based on microscope and mesoscope,such as kinetic monte carlo (KMC) method, lattice boltzmann method (LBM) and molecular dynamics (MD), is important, even is the only research method for space-time multiscale characteristics of complex physical and chemical processes.Because these fine monoscale simulation methods depend entirely on fine scale simulators(models),and must pass simulators to calculate each evolutionary step in proper order,the challenge of huge memory spending and large CPU time consuming often appear,so that the simulations can't go into actual operation.Coarse projective integration methods only need to calculate a small amount of evolution steps by fine scale simulators, and then the evolution obtained macro parameters is reasonably extrapolated using traditional numerical method, macro parameters of follow-up evolution steps could be obtained quickly and precisely,thus meet the system research needs.Therefore, coarse projective integration multiscale research for various complex physical and chemical processes of advanced energy system has an important theoretical and practical value.In this thesis coarse projective integration simulation concept is introduced into reaction-diffusion phenomenons of advanced energy system for realizing multiscale simulation based on the framework. Main research contents are as follows:â‘ Giving simulation mechanism coarse projective integration methods detailedly, and telescopic projective integration multiscale framework for advanced energy system reaction diffusion is preliminary established.â‘¡Try to do teleprojective euler multiscale simulation on typical Schlogl and Selkov reaction diffusion phenomenon in advanced energy system based on microscopic and mesoscopic (two fine) scales,and compared emphatically with fine monoscale simulation.Schlogl and Selkov reaction diffusion lattice boltzmann model (mesoscopic simulator) and kinetic monte carlo model (micro simulator) are respectively established on microscopic and mesoscopic scales,lifting operators and restriction operators of each reaction diffusion are extracted according to the real-time multiscale association of Schlogl,Selkov reaction diffusion, then the effective dynamic coupling between these operators and the mesoscopic/micro simulators is achieved. Reactant concentration is extrapolated with secondary telescopic projective forward Euler type effectively. â‘¢Proposing a telescopic projection Adams method based on the electrochemical reaction process of fuel cells.The telescopic projection adams multiscale simulation analysis based on mesoscopic scale is done about the distribution of hydrogen, oxygen and water vapor,et al in the electrode/port of gas,with the electrochemical reaction-diffusion process of solid oxide fuel cell (SOFC) for an example. It verifies the accuracy and efficiency of this method through the simulation results of monoscale LBM and TPE with comparisonâ‘£The electrochemical performance of SOFC are firstly researched in multi-scale point of view with telescopic projection Adams multiscale simulation from mesoscopic scale.LBM models of SOFC electrochemical reaction (mesoscopic simulator) are established under different working conditions, lifting operators and restriction operators are constructed according to macroscopic and mesoscopic electrochemical characteristics of SOFC, telescopic projection extrapolating process is implemented to utilize the forecast -- correction advantage of second order Adams-Bashforth numerical method, thus the internal electrochemical properties of SOFC are more truely revealed through dynamic simulation experiment of different Influence factors.This paper has effectively realized telescopic projective integration multiscale simulation for several reaction-diffusion phenomenons in advanced energy system. Simulation results show that the telescopic projective integration for simulating reaction diffusion not only powerful dissolve the problem of huge memory spending and large CPU time consuming in fine monoscale simulation, but also more truly reveals the inherent characteristics of reaction diffusion by scale coupling from fine bottom,it laid a foundation for more complex and deeper reaction diffusion simulation research in energy system. In addition, appling the multiscale simulation concept in other physical chemistry phenomenons of advanced energy system is also a very important research direction in the future,and then multiscale simulation general framework of advanced energy system will be set up.