基于CFD数值模拟的高固厌氧消化搅拌设备优化分析

Optimization Analysis of High Solids Anaerobic Digestion Stirring Equipment Based on CFD

高固厌氧消化(High Solid Anaerobic Digestion,HSAD)相比传统厌氧消化存在混合效果差、能量转换效率低等缺点,而机械搅拌不仅促进消化,同时有效解决高固厌氧消化受高黏度非牛顿流体限制的问题。本研究基于气液两相流混合模型,借助计算流体力学(Computational Fluid Dynamics,CFD)对3类高固厌氧反应器的流场进行数值模拟,探寻最佳工况。研究表明,螺带搅拌桨在高黏度流体混合中具有优越性;同时根据不同转速下反应器内的流场与死区分析,得到3类搅拌反应器混合特征,为实际高固厌氧消化搅拌机械的选用提供了理论指导。

Compared with traditional anaerobic digestion,high solids anaerobic digestion(HSAD)has disadvantages such as poor mixing effect and low energy conversion efficiency.Mechanical stirring can promote digestion and effectively solve the problem that high-viscosity non-Newtonian fluids limit high-solids anaerobic digestion.In this study,based on the gas-liquid two-phase flow mixing model,the flow field of three types of high-solids anaerobic reactors was numerically simulated by means of computational fluid dynamics(CFD)to explore the optimal working conditions.The research shows that the screw-ribbon impeller has advantages in mixing high-viscosity fluids.At the same time,according to the analysis of the flow field and the dead zone in the reactor at different speeds,the mixing characteristics of three types of agitated reactors are obtained,which provided theoretical guidance for the selection of the actual high-solids anaerobic digestion stirring and transmission machinery.