Analysis of the Heat and Mass Transfer Process and Entropy in Electroosmotic Flow
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摘要: 在壁面存在恒定热通量条件下,分析微通道内电渗流中传热传质过程与熵的生成.建立数值计算模型,分别采用Poisson-Boltzmann方程、Navier-Stokes方程、Nernst-Planck方程和能量方程来描述微通道内双电层电势、流场、离子浓度和温度的分布情况.引入熵产生,进一步研究不同流动参数对流体传热过程的作用,讨论不同流动参数下各热效应的变化规律,并具体分析热效应参数对流体总熵增加及各部分热效应对总熵比重的影响.结果表明,动电参数与Joule(焦耳)热系数的增大会使得传热性能减弱,动电参数对传热性能影响更为明显;流体的总熵为动电参数、传质系数和质量弥散系数的增函数.Abstract: The heat and mass transfer process in microchannels was analyzed with constant heat flux through the wall. In the numerical calculation model, the electric double layer potential, velocity, ion concentration and temperature distribution were characterized with the Poisson-Boltzmann equation, the Navier-Stokes equation, the Nernst-Planck equation and the energy equation, respectively. The effects of different flow parameters on each thermal index in the heat and mass transfer process were investigated by means of the entropy generation, and the influences of important flow parameters on the total entropy generation and the proportion of each thermal effect were discussed in detail. The results reveal that, the increases of the kinetic parameters and the Joule heating coefficient weaken the heat transfer performance, and the influence of the kinetic parameters is more evident. The total entropy of the flow is an increasing function of the kinetic parameters, the mass transfer coefficient and the mass dispersion coefficient.
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Key words:
- electroosmotic flow /
- heat and mass transfer /
- entropy
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