煤粉无焰燃烧的数值模拟

Numerical Simulation of Pulverized-coal Flameless Combustion

用组分输运方法对煤粉的无焰燃烧进行了数值模拟,湍流采用Realizable k-ε紊流模型,颗粒相采用随机轨道模型,挥发分的析出采用化学渗透模型(CPD),湍流化学反应采用涡耗散模型(Eddy-Dissipation),煤粉颗粒表面燃烧模拟采用内表面化学反应动力学模型,辐射传热采用P-1辐射模型.结果表明,实验数据与数值模拟吻合良好;煤粉无焰燃烧时,燃烧反应发生在整个炉膛空间,炉内温度分布较均匀,温差为200K左右,燃烧呈现低O2浓度特征,NOx排放浓度较低.

Numerical simulation of flameless combustion of pulverized coal was carried out by species transport method.Realizable k-ε model was used to simulate gas phase turbulent.The solid phase was solved by particle stochastic trajectory model.Thermal volatilization was made by the CPD model.Turbulent chemical reaction was simulated via eddy dissipation model.Intrinsic model was used to simulate Particle of pulverized coal surface combustion.Radiation heat transfer simulation was carried out with P-1 radiation model.The result shows that experimental data are accurately predicted by the numerical simulation.Flameless combustion takes place in whole furnace,the maximum temperature difference is about 200K and the temperature is well-distributed in furnace.The flameless combustion is in low O2 concentration and low emission of NOx.