适用于工程仿真的大涡模拟与化学反应模型

Large Eddy Simulation and Chemical Reaction Model for Engineering Simulation

针对大尺度气体爆炸工程问题数值模拟的需求,基于层流火焰厚度与初始压力的关系,改进了传统的增厚火焰模型,使增厚因子能够根据当地压力自动调整大小.同时,基于开源程序Canter和遗传算法,提出了能够准确计算层流火焰速度、火焰面厚度及其随压力变化的多组分单步化学反应模型.集成发展的大涡模拟、化学反应模型与多组分反应流有限差分计算程序,开展了封闭管道氢气空气爆炸数值模拟.通过与试验对比,研究了大涡模拟模型、网格大小、化学反应模型对计算结果与效率的影响.结果表明:相比于详细反应模型,新单步氢气空气简化反应模型节省了60%的计算时间,极大提高了气体爆炸三维数值模拟的计算效率.

To meet the needs of numerical simulation of large-scale gas explosion engineering,based on the rela-tionship between laminar flame thickness and initial pressure,the traditional thickening flame model was im-proved so that the thickening factor could automatically adjust according to local pressure.At the same time,based on the open source program Cantera and genetic algorithm,a multi-component single step chemical reac-tion model capable of accurately calculating laminar flame velocity,flame surface thickness and their variations with pressure was proposed.The large eddy simulation,chemical reaction model and multi-component reaction flow finite difference simulation code were integrated to carry out the numerical simulation of hydrogen air ex-plosion in closed pipes.The effects of large eddy simulation model,grid size and chemical reaction model on the calculation results and efficiency were studied by comparison with experiments.The results show that compared with the detailed reaction model,the new single step hydrogen air simplified reaction model saves 60%of calcu-lation time,and greatly improves the calculation efficiency of three-dimensional numerical simulation of gas ex-plosion.