凹槽通道中脉动流动强化传质的数值研究

对脉动流动强化凹槽通道中的传质进行了数值研究,探讨了雷诺数Re、斯德鲁哈尔数St、脉动振幅A以及凹槽的几何结构等参数对通道中流动和传质特性的影响.研究发现,受流体速度脉动的影响,凹槽中的漩涡发生周期性的形成和脱落,从而增强了流体间的相互掺混,这是强化传质的关键因素之一.在脉动流动下,通道内的传质能力得到很好地强化,尤其是凹槽内部的局部传质性能更佳.传质的强化效果随着Re和A的增大而增强,而且对于该模型存在最佳的St,它与凹槽的几何结构有很大关系.

Numerical Study on Enhancing Mass Transfer in Grooved Channel by Pulsating Flow

Enhancing mass transfer in periodic square grooved channels by a laminar pulsating flow was studied numerically. Comprehensive research was conducted to investigate the influence of several main parameters on flow characteristics and mass transfer enhancement in the grooved channel. These parameters are Renolds number Re, Strouhal number St, pulsation amplitude A,and geometrical characteristics of the cavity. The results obtained indicate that, due to the flow pulsation, the vortex in cavity periodically bursts and then sheds.This periodic shedding of vortices contributes to the bulk chaotic mixing of fluid which is the main factor of mass transfer enhancement. By pulsating flow, the mass transfer rate of the channel is enhanced at a large extent, especially the local mass transfer in the cavity. The enhancement of mass transfer rate increases with the Re and A.There exists an optimal Strouhal number for the greatest enhancement of mass transfer in this model, which appears to have a strong relation with the geometrical characteristics of the cavity.