【摘要】 以DFM模型(Diffusive Flux Model)为基础,建立了颗粒的质量传递方程,之后以Fluent为计算平台,结合其UDF和UDS功能,对高浓度悬浮液在直型微通道中的流动和颗粒定态平衡分布进行了CFD模拟。研究中首先模拟非布朗悬浮液在常规通道中的流动,通过与文献结果的比较验证了建立的数学模型和求解方法的正确性。然后模拟悬浮液在微通道中的流动,分析了计算模型用于微通道模拟应做的修正,确定了相关参数,并考察了颗粒浓度、粒径、悬浮液流动速度及Pe数对通道中颗粒分布的影响,特别是明确了布朗运动对悬浮液流动的影响。模拟结果表明,DFM-CFD模拟结果与实验结果具有较好的一致性,优于文献中SBM(Suspension Balance Model)-CFD的模拟结果。更多还原

【Abstract】 Flow of concentrated suspension in a microchannel was simulated by Fluent(CFD package), and a particle mass-transport equation was built based on Diffusive Flux Model(DFM) and solved with continuity equation and momentum equation. The simulation method was first validated by comparing the simulation result of the non-Brownian suspension flow in a micrometer channel with the experimental and theoretical data in literature. The flow of suspension in a microchannel was then studied. And necessary modification of the computation model and the relative parameters due to the microscale effect were analyzed. Subsequently, the effects of particle concentration, particle size, flow velocity, and Pe number on particle distribution were investigated, and the influence of Brownian motion was clarified. After applying DFM in the simulation, the CFD results show good agreement with the experimental results, which are better than that by using Suspension Balance Model(SBM) in literature.更多还原