两股无预混流体湍流混合与反应过程的数值模拟

旋转填充床作为新型的高效反应传质设备，广泛应用于快速反应过程，如制备纳米粉体材料.但是旋转床内的混合机理以及混合与反应的相互关系尚不清楚.作为旋转填充床内流动、混合与反应过程一种初步的简化，针对两股无预混反应物料在通过丝网之后的湍流混合、扩散及反应行为进行了数值模拟研究，以求为实际应用中涉及多层丝网的旋转床内的混合反应机理的研究提供基础.对两股无预混反应物料的湍流流动与组分混合过程，应用双方程k-ε湍流模型进行了模拟计算.对于所涉及的化学反应过程，建立了瞬时封闭模型进行模拟.模拟的混合层厚度、平均浓度及浓度协方差等与文献公认结果进行了对比，二者吻合良好，平均浓度的偏差不超过10%.

NUMERICAL SIMULATION OF TURBULENT MIXING AND REACTION PROCESS OF TWO NON-PREMIXED REACTANTS

Mixing in the rotating packed bed is extensively intensified and therefore is of great potential as a novel reactor for fast reactions such as reactive precipitation to synthesize nanoparticles. However, the mixing mechanism and the effect of mixing on reaction have not been elucidated yet. In this paper, a new model to simulate the turbulent reactive mixing between two non-premixed reactants flow through a single net grid is presented in order to help understand the mechanism and the effect of mixing in the rotating packed bed. The standard k-ε turbulent model is applied and the momentary closure for the covariance in the equations of species transfer which are similar to the methodology presented by Toor is set up. The mixing layer thickness, mean concentration and concentration covariance are simulated under the experimental conditions reported by Saetran et al and it is found that calculational values by the model are in good agreement with the experimental results with average deviation of mean concentration less than 10%.