Numerical investigation of near-critical fluid convective flow mixing in microchannels
Numerical investigation of near-critical fluid convective flow mixing in microchannels
复制标题
DOI：
10.1016/j.ces.2013.04.010
复制
发表时间：
2013-06
影响因子：
4.7
通讯作者：
Lin Chen;Xin‐Rong Zhang;J. Okajima;S. Maruyama
中科院分区：
文献类型：
--
作者：
Lin Chen;Xin‐Rong Zhang;J. Okajima;S. Maruyama
超临界CO2流体已广泛应用于化学萃取、化学合成、微制造和传热装置等领域。目前的研究涉及近临界CO2微通道混合流及其基本特性。通过求解耦合计算流体动力学方程来进行仔细的数值研究。结果表明，微通道内可以在相对较宽的初始条件和控制条件下实现强的近临界涡流。模拟基本的等温流动，然后将其用作热对流模拟的初始状态。施加壁面热流后，在高度D=100μm～200μm的微通道中，涡流混合流源自热边界，而在D=300μm～500μm的微通道中，自然对流将逐渐占主导地位。当前的微混合演化可以归因于一种新型的开尔文-亥姆霍兹不稳定性。为有效的近临界微通道混合情况确定了良好相关的特征数。研究发现微通道中涡流的生长和演化模式与以往的微混合方法有很大不同。本研究还讨论了在微工程/化学过程中的可能应用。
Supercritical CO2fluid has been widely used in chemical extraction, chemical synthesis, micro-manufacturing and heat transfer apparatus, and so forth. The current study deals with near-critical CO2microchannel mixing flow and its basic characteristics. Careful numerical investigations are carried out by solving the coupled computational fluid dynamic equations. The results show that strong near-critical vortex flows can be achieved in a relatively wide range of initial and controlling conditions in microchannels. Basic, isothermally developed flows are simulated and then used as the initial state for a heat convective simulation. After the wall heat flux is applied, the vortex mixing flow originates from the hot boundaries in microchannels with height D=100μm to 200μm, while natural convection will gradually become dominant for microchannels with D=300μm to 500μm. The current micro-mixing evolution can be ascribed to a novel type of Kelvin–Helmholtz instability. Well-correlated characteristic numbers are identified for the effective near-critical microchannel mixing cases. The vortex growth and evolution mode in microchannels are found to differ greatly from previous micro-mixing methods. Possible applications in micro-engineering/chemical process are also discussed in this study.