Abstract In this paper we develop a computational model for the mixing and transport of a dilute biomass slurry. The objective was to create a sufficiently simple and efficient model for biomass transport that can be coupled with reaction models for the study of conversion of cellulosic biomass into fermentable sugars. Our target system is 5%-by-mass α -cellulose, which is our proxy for more complex lignocellulosic biomass. In the authors’ previous work, an experimental investigation with α -cellulose under two vane-mixer configurations showed a bifurcation between a settling regime, for which settling effects dominate, and a suspended regime, for which solids are mostly suspended. Here, a mixed-fluid model was chosen, for which the model for the mixture-velocity field is the incompressible Navier-Stokes equations under the Boussinesq approximation for buoyancy. Solids transport includes solids motion due to diffusion, settling, advection, and shear. Comparison of simulated and experimental results show good agreement in the suspended regime, and in capturing the bifurcation rate. While the model captured well the distribution of solids in the settling regime, the model was incapable of capturing the high torque values seen in experiments with vanishing mixer rotation rate.

中文翻译：

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进行旋转混合的稀生物质浆的计算模型的制定和验证

摘要 在本文中，我们开发了一种用于混合和运输稀生物质浆料的计算模型。目标是创建一个足够简单和有效的生物质运输模型，该模型可以与反应模型相结合，以研究纤维素生物质转化为可发酵糖。我们的目标系统是 5% 质量的 α-纤维素，这是我们代表更复杂的木质纤维素生物质。在作者之前的工作中，在两种叶片混合器配置下对 α-纤维素进行的实验研究表明，在沉降效果占主导地位的沉降状态和悬浮状态之间存在分歧，其中固体大部分悬浮。在这里，选择了混合流体模型，其中混合速度场的模型是浮力 Boussinesq 近似下的不可压缩 Navier-Stokes 方程。固体输送包括由于扩散、沉降、平流和剪切引起的固体运动。模拟和实验结果的比较表明，在悬浮状态和捕获分叉率方面具有良好的一致性。虽然该模型很好地捕捉了沉降状态中固体的分布，但该模型无法捕捉在搅拌器转速消失的实验中看到的高扭矩值。