| Summary: | 博士 === 中興大學 === 應用數學系所 === 99 === This study numerically investigates the electroosmotic flow and heat transfer in a wavy surface of the micro-channels. For the case of wavy micro-tube, the solution takes the electrokinetic effect and the amplitude of the wavy surface into consideration. A simple coordinate transformation method is used to transform a complex wavy micro-tube into a regular, circular tube. The governing equations, including the Poisson-Boltzmann equation, the modified Navier-Stokes equations, and the energy equation with their corresponding boundary conditions are also transformed into the computational domain and then solved by the finite difference method. In chapter 2 , the main objective is to investigate the difference of fluid flow and temperature fields for various wavelength ratio and the electrokinetic parameter .
In chapter 3 and chapter 4, we want to research how the fluid flow and temperature fields are dominated by kinds of wavelength ratio 、Knudsen number、Eckert number、heat generation G and potential ratio. Results show that the distributions of the skin-friction coefficient and the local Nusselt number are oscillatory along the stream-wise direction for the wavy micro-tube . The amplitude of the oscillated local Nusselt number increases with an increase in the electrokinetic parameter and wavelength ratio , but that of the skin-friction coefficient decreases with an increase in the electrokinetic parameter . The heat transfer enhancement is significant for larger electrokinetic parameter and wavelength ratio .The distributions of the local Nusselt number and skin-friction coefficient domenstrate that are oscillatory along the stream-wise direction for the wavy micro-tube .
The oscillated local Nusselt number amplitude increase with an increase in the Knudsen number, heat generation G, Eckert number and wavelength ratio , but skin-friction coefficient amplitude decreases as the Knudsen number increases.
The positive potential increases the velocity, and the negative potential decreases the velocity, even creates back flow,. In wall temperature, the positive potential enhances the heat transfer effects than negative potential does. The amplitude of local Nusselt number and skin-friction coefficient increases as an increase of the potential ratio.
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