适用生物质及煤热解CFD模拟的DAEM近似计算方法

Approximation of the distributed activation energy model( DAEM)for computational fluid dynamics( CFD) simulations of coal or biomass pyrolysis

生物质以及煤粒的复杂热解反应可用分布活化能模型(DAEM)模拟,但将此模型直接应用于计算流体力学(CFD)模拟计算量极大,因为在每个时间步中对每个计算网格都要计算多重积分。因此,本文提出了DAEM的近似计算方法以使其能够合并在CFD程序的计算中。简化后的模型能够较精确预测热解产物产率和生成速率;此外,改进后的模型的计算量大大减少,可适用于较宽泛的加热环境下,且模型预测结果与生物质或煤粒热解实验得到的结果能够很好的吻合。

The complex decomposition kinetics of coal or biomass is usually interpreted with the distributed activation energy model( DAEM). However,when applied directly in computational models,this model is highly computationally intensive,because it requires multiple integrations at every time step for each computing grid. The present work proposes an approximation of the DAEM to make it more convenient to incorporate in computational model code. The method significantly reduces the computational time and cost. In addition,it affords the yield of pyrolysis products and the rate of production exactly. Furthermore,the model predictions fitted well with the experiment data for biomass and coal pyrolysis.