具等熱通量微流道內電滲流之對流熱傳

Convective heat transfer for electro-osmotic flow in a microchannel with constant surface heat flux

張益壽(Yi-shou Chang)

國立虎尾科技大學/工程學院/機械與機電工程研究所/碩士(2008年)

https://doi.org/10.6827/NFU.2008.00008

摘要

本論文旨在研究在微流道中電滲流之對流熱傳現象，揭示微流道電滲流的熱完全發展流的熱流特性，探討微流道高度與Debye-length比，無因次化體積熱產生，無因次化壓力梯度與外加電場強度的比對在微流道中流體的速度分佈、溫度分佈與紐塞爾數的影響。在電滲熱流場理論分析中，使用數學模式包括(i)解Poisson-Boltzmann方程式以求得微流道電位分佈，(ii)解動量方程式以求得在微流道速度分佈，(iii)解能量方程式以求得微流道中考慮焦耳熱時之流體溫度分佈。考慮的邊界條件為在微流道壁面為存在zeta電位，無滑動邊界條件和等熱通量條件。在研究結果顯示當無因次化微流道高度與Debye-length比增加時速度分佈會呈現平坦，溫度分佈呈現微流道壁面溫度比微流道中心處溫度高。當壓力梯度與外加電場強度比增加時，紐塞爾數相對減少。

並列摘要

In the present work, an analysis is performed to explore the heat transfer characteristics of electro-osmotic flow in a microchannel. Representative velocity and temperature distributions, as well as the Nusselt number are presented for thermally fully developed flow for a wide range of governing parameters. These parameters include the ratio of microchannel height to double layer thickness, the ratio of pressure force to electro-osmotic force, and the non-dimensional volumetric heat generation parameter. The solution procedure is as follows: (i) solve the Poisson-Boltzmann equation to obtain the potential distribution in the EDL (ii) solve the momentum equation to get the velocity distribution in microchannel (iii) solve the energy equation to obtain the temperature distribution in microchannel. Suitable boundary conditions are zeta potential at the wall, no-slip velocity condition at the wall, and constant surface heat flux condition. The present results show that the velocity profile becomes flatter as the ratio of microchannel height to double layer thickness becomes larger. Also, an increase in the ratio of pressure force to electro-osmotic force produces a decrease in the Nusselt number.

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