新型错流旋转填料床气相流场的三维CFD模拟

3D CFD simulation of gas flow in new cross flow rotating packed bed

目前鲜有关于错流旋转填料床结构改进研究方面的报道。以自主研发的错流旋转填料床为计算模型,建立了三维物理模型,采用标准k-ε湍流模型和SIMPLE算法,填料层用多孔介质模型,运用CFD方法对其内部气相流场进行了模拟,研究了转速和气量对速度场和干床压降的影响规律,并通过实验进行了验证。由结果可知:干床压降几乎不受转速的影响,模拟值与实验值相对误差在11.2%以内;旋转填料层内气相流场主要以旋流场为主,切向速度与填料线速度大小相当,且不受气量的影响。轴向速度值受气量的影响,其径向分布受转速的影响。与切向速度和轴向速度相比,径向速度小1—2个数量级,说明气体在径向的偏移量很小;中间静止填料层能够有效减小气旋,强化气相流场扰动,表明新型错流旋转填料床能够强化气相传质。

There were few reports about the structure improvement of cross flow rotating packed bed at present. The self-developed cross flow rotating packed bed was chosen as a simulation model, and the 3D physical model was established. Standard k-~ turbulent model and SIMPLE algorithm were used in the calculation. The packing layer was modeled by porous medium model. Computational fluid dynamics （CFD） method was employed to simulate the gas flow in the new cross flow rotating packed bed. The effects of rotating speed and gas flow rate on the velocity field and the dry pressure drop were investigated. The simulation data were verified by experimental data. The results show that the effect of rotating speed on dry pressure drop is not obvious. The relative error of the simulation value and experiment value is less than 11.2%. The rotating flow field plays a major role within gas flow field in rotating packed layer. The tangential velocity value is nearly equal to the value of packing linear velocity. The axial velocity value is affected by the gas flow rate. The radial distribution mainly depends on the rotating speed. Compared with the tangential velocity and axial velocity, the radial velocity value is lower by 1-2 orders of magnitude, indicating that the radial offset is very small The middle static packing layer can effectively reduce the cyclone and strengthen the gas flow disturbance, indicating that the new cross flow rotating packed bed can intensify the gas phase mass transfer processes.