柔性圆柱形微管道内的电动流动及传热研究

Electrokinetic Flow and Heat Transfer in Soft Microtubes

研究了在纯压力驱动下,流体通过壁面带有某种电荷的聚电解质层(PEL)的微管道,即柔性微管道的电动流动和热传输特性.基于先前得到的电势和速度的解析解以及流向势的数值解,在热充分发展的情况下,假设壁面热流恒定,利用有限差分法求解了包括黏性耗散和Joule(焦耳)热影响下的能量方程,获得了无量纲温度数值解.通过数值计算,给出了相关的无量纲参数对速度、温度以及Nusselt(努赛尔)数的影响.研究表明,当其他参数固定时,无量纲速度和温度随着无量纲聚电解质层厚度d的增大而减小,随着聚电解质层中等效双电层厚度与双电层厚度之比K_λ的增大而增大;Nusselt数随着Joule热系数S的增大而减小,随无量纲聚电解质层厚度d的增大而减小,随着K_λ的增大而增大.

The electrokinetic flow and heat transfer characteristics of fluid in soft microtubes, of which the walls were covered by polyelectrolyte materials as the fixed charge layer, were studied based on previously obtained analytical solutions of electrical potentials and velocities, and numerical solutions of streaming potentials. Under the assumption of a constant wall heat flow, the energy equations including the effects of viscous dissipation and Joule heat were solved with the finite difference method and numerical solutions of the dimensionless temperature were obtained. Numerical calculations also gave the influences of related dimensionless parameters on the velocity, the temperature and the Nusselt number. The study shows that, when other parameters are fixed, the dimensionless velocity and temperature decrease with thickness d of the polyelectrolyte layer but increase with equivalent electric double layer to electric double layer thickness ratio Kλ;the Nusselt number decreases with Joule heat coefficient S and polyelectrolyte layer thickness d,but increases with Kλ.