本文關(guān)鍵詞：微管道中納米流體流動及傳熱研究　出處：《內(nèi)蒙古大學(xué)》2016年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 納米流體 能量傳遞 雙電層 流動電勢 洛倫茲力

【摘要】：近些年來,能源的開發(fā)及可持續(xù)利用問題正受到人們越來越多的關(guān)注.特別是在飛速發(fā)展的微型制造工藝和微細(xì)加工技術(shù)的影響下,微機(jī)電系統(tǒng)(MEMS)對熱交換設(shè)備的換熱性能也提出了更高的要求.納米流體的誕生適應(yīng)了這種發(fā)展的潮流,其改良的液體導(dǎo)熱性能,顯著地提高了系統(tǒng)的傳熱效率,而且流體本身不易發(fā)生粒子沉淀及對流道磨損和堵塞等問題,極大地拓展了其在工業(yè)領(lǐng)域中的應(yīng)用.微流體系統(tǒng)本身具有特殊的微尺度效應(yīng)、毛細(xì)效應(yīng)、滑移效應(yīng)、快速熱傳導(dǎo)效應(yīng)等.基于這些不同的效應(yīng),微通道內(nèi)流體運(yùn)動的實(shí)現(xiàn)手段也有多種方式,例如利用壓力、表面張力,電場力、磁場力、高頻聲波等.尤其是在當(dāng)下迅速發(fā)展的電泳系統(tǒng)中,電滲流是占主導(dǎo)地位的驅(qū)動技術(shù)之一.由于電滲驅(qū)動具有高效率、易控性、且不會對機(jī)械構(gòu)件造成破壞等優(yōu)點(diǎn),目前它被廣泛的應(yīng)用于生物、化學(xué)和醫(yī)學(xué)等領(lǐng)域.流動電勢同樣可以引發(fā)微系統(tǒng)的電滲流動,而流動電勢本身就是一種特殊的電滲現(xiàn)象.不同于普通的電滲流誘導(dǎo)機(jī)制,這種電滲流動不需要外部電場的介入.對于流動電勢的研究相對成熟,無論在理論分析還是實(shí)驗檢驗方面,都取得了豐富的成果.但是我們也看到,納米流體在流動電勢研究方面的報道還是很匱乏.同時,作為微流體有效驅(qū)動機(jī)制的磁場力即洛倫茲力被普遍應(yīng)運(yùn)于多種研究領(lǐng)域中,特別是在納米流體的流動及傳熱問題中.在洛倫茲力的分析中,很多的研究工作都將電場的產(chǎn)生單純視為流體運(yùn)動與外加磁場的綜合效應(yīng),而忽略了外部電場的應(yīng)用.然而,外加電場同樣會對微系統(tǒng)產(chǎn)生顯著的影響.基于以上的分析,本文著重研究了流動電勢作用下平行微管道及圓形微管道中納米流體的流動與傳熱.進(jìn)一步地分析了多場耦合作用下微管道內(nèi)納米流體的流動及傳熱機(jī)理.另外,我們考慮外部電場的情形下,探究了微管道中EMHD納米流體的流動及熱量傳遞問題.在本文的分析中,我們建立了雙電層(EDL)及電場勢所滿足的Poisson-Boltzman方程,求解電場勢分布,進(jìn)而獲得描述電場力的電荷密度分布.再將流動電勢及電場力代入納米流體所滿足的修正動量及能量方程中,在不同邊界條件下,解析求解了納米流體流場的速度及溫度分布,并獲得了描述納米流體熱量傳遞的重要參數(shù)努賽爾數(shù)(Nusselt number)的解析表達(dá).
[Abstract]:In recent years, problems of development and sustainable utilization of energy is more and more attention. Especially in the rapid development of micro manufacturing technology and micro machining technology, micro electro mechanical system (MEMS) on the heat transfer performance of heat exchange equipment is also put forward higher request. The birth of nano fluid to the development trend of liquid thermal conductivity improved, significantly improve the heat transfer efficiency of the system, and the fluid itself is not easy to happen particle precipitation and convection road wear and clogging problems, greatly expanding its application in the industrial field. The micro fluid system itself has the special effect of micro scale, capillary effect, slip effect, fast heat conduction effect. These different effects based on microchannel fluid motion means there are a variety of ways, such as the use of pressure, surface tension, electric field and magnetic field Force, high frequency sound waves. Especially in the current rapid development of electrophoresis system, the electroosmotic flow is one of the dominant driving technology. Due to electroosmotic driving with high efficiency, easy to control, and will not cause damage to mechanical components and other advantages, it has been widely used in biology, chemistry and medicine and other fields. Flow the potential can also initiate the electroosmotic flow in micro systems, and the potential flow itself is a kind of special phenomenon. Different from the electroosmotic electroosmotic flow induced mechanism, the electroosmotic flow does not require an external electric field. The intervention is relatively mature research for flow potential, both in theory or experiment, get rich results. But we also see that the reports of nanofluids in flow potential research is very scarce. At the same time, the magnetic force as the driving mechanism of the micro fluid force by Lorenz Generally applied in many research fields, especially in the flow and heat transfer problems of nanofluids. Analysis in Lorenz force, a lot of research work will produce electric field treated as a comprehensive effect of fluid motion and external magnetic field, while ignoring the application of an external electric field. However, the electric field will also have a significant the effect of micro system. Based on the above analysis, this paper focuses on the flow and heat transfer of nano fluid flow under the action of potential parallel micro channels and circular microchannels. Further analysis of the flow and heat transfer mechanism of micro channel flow meters extend under multi field coupling. In addition, we consider the external electric field situation to explore the EMHD nano fluid flow and heat transfer in microchannels. In this paper, we established the electric double layer (EDL) and the electric potential satisfy the Poisson-Boltzman equation, solution The potential distribution of the electric field, and then obtain the charge density distribution is described. The electric force correction of momentum and energy equation of flow potential and electric field force meet into nano fluids in under different boundary conditions, analytical solution of the velocity and temperature distribution of nano fluid flow, important parameters and won the description of Nu nano fluid heat transfer the number of (Nusselt number) of the analytical expression.
【學(xué)位授予單位】：內(nèi)蒙古大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：O35

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