本文選題：電滲流 + 多場(chǎng)耦合��； 參考：《哈爾濱工業(yè)大學(xué)》2016年碩士論文

【摘要】：電滲流是微流控技術(shù)和微全分析系統(tǒng)中最為重要的流體驅(qū)動(dòng)方式之一,因其簡(jiǎn)單高效而得到了較為普遍的應(yīng)用。隨著流體控制技術(shù)逐漸向著復(fù)雜化和微型化發(fā)展,其內(nèi)部流動(dòng)細(xì)節(jié)及微觀結(jié)構(gòu)逐漸成為人們所關(guān)注的重點(diǎn)。由分子動(dòng)力學(xué)(MD)演化而來(lái)的能量守恒耗散粒子動(dòng)力學(xué)(eDPD)是一種基于粒子的新興拉格朗日數(shù)值方法,相比MD具有更高的效率和更強(qiáng)的靈活性,對(duì)于模擬復(fù)雜流體的流動(dòng)與傳熱問(wèn)題具有先天性的優(yōu)勢(shì)。作為一種新興的介觀方法,eDPD的發(fā)展和應(yīng)用目前還較為有限,對(duì)于多物理場(chǎng)耦合的流動(dòng)傳熱問(wèn)題更是鮮有涉及。本文研究的主要目的就是將其用于電場(chǎng)、流場(chǎng)及溫度場(chǎng)耦合下的電滲流動(dòng)與傳熱的模擬。首先詳細(xì)地介紹了電滲流動(dòng)與傳熱的控制方程及eDPD方法模擬復(fù)雜流動(dòng)與傳熱問(wèn)題的理論基礎(chǔ),并闡明了eDPD系統(tǒng)中實(shí)現(xiàn)多物理場(chǎng)耦合的一般方法,通過(guò)模擬簡(jiǎn)單微通道內(nèi)的純電滲流及有壓差驅(qū)動(dòng)下的混合電滲流動(dòng)與傳熱過(guò)程,將得到的結(jié)果分別與理論解及有限元方法(FEM)對(duì)比,驗(yàn)證了該方法的正確性。微混合技術(shù)在微流體控制及輸運(yùn)中起著強(qiáng)化傳質(zhì)與傳熱的核心作用,對(duì)于設(shè)備的微型化和集成化具有重要的意義。本文通過(guò)改變微通道壁面的異質(zhì)電勢(shì)分布結(jié)構(gòu),采用eDPD方法分別對(duì)橫向和縱向電場(chǎng)作用下的電滲微混合與傳熱問(wèn)題進(jìn)行了模擬,分析了壓力梯度及壁面電勢(shì)等對(duì)微混合產(chǎn)生的相關(guān)影響。研究發(fā)現(xiàn)不同方向電場(chǎng)作用下的微混合流態(tài)具有較大的差異,而壓力梯度的增加會(huì)導(dǎo)致電滲混合與傳熱的整體效果逐漸減弱。誘導(dǎo)電滲流是近十幾年才被發(fā)現(xiàn)和提出的一種電動(dòng)新現(xiàn)象,與傳統(tǒng)電滲流相比能夠?qū)ξ⒘黧w產(chǎn)生更好的驅(qū)動(dòng)效果,而其內(nèi)部規(guī)律尚未被完全了解,因此具有很高的研究?jī)r(jià)值。本文首次將eDPD方法應(yīng)用于圓柱電極誘導(dǎo)電滲流動(dòng)與傳熱問(wèn)題的研究,分析了有壓差存在下電極材料結(jié)構(gòu)變化時(shí)的誘導(dǎo)電滲流動(dòng)與換熱特性,發(fā)現(xiàn)電極材料結(jié)構(gòu)對(duì)其附近的流態(tài)有較大的影響,左側(cè)導(dǎo)體材料誘導(dǎo)產(chǎn)生的電滲渦流削弱了壓力梯度的作用,而右側(cè)渦流對(duì)壓力驅(qū)動(dòng)流則具有一定的促進(jìn)效果。本文的研究充實(shí)了介觀尺度下的電動(dòng)力學(xué)理論,成功地將eDPD方法應(yīng)用于多物理場(chǎng)耦合復(fù)雜流動(dòng)與換熱問(wèn)題的研究,拓展了其模型的應(yīng)用領(lǐng)域并充分證明了其可靠性及靈活性,為其在相關(guān)方向的發(fā)展奠定了一定的基礎(chǔ)。
[Abstract]:Electroosmotic flow (EOF) is one of the most important fluid driving methods in microfluidic control technology and micro-total analysis system. It has been widely used because of its simplicity and efficiency. With the development of fluid control technology towards complexity and miniaturization, the internal flow details and microstructure gradually become the focus of attention. The energy conservation dissipative particle dynamics (PDD) evolved from molecular dynamics (MD) is a new Lagrangian numerical method based on particles, which is more efficient and more flexible than MD. It has an inherent advantage in simulating the flow and heat transfer of complex fluids. As a new mesoscopic method, the development and application of eDPD is still limited, and the heat transfer problem of multi-physical field coupling flow is rarely involved. The main purpose of this study is to simulate the electroosmotic flow and heat transfer under the coupling of electric field, flow field and temperature field. Firstly, the governing equations of electroosmotic flow and heat transfer and the theoretical basis of eDPD method for simulating complex flow and heat transfer are introduced in detail, and the general method to realize multi-physical field coupling in eDPD system is also expounded. By simulating the pure electroosmotic flow and the mixed electroosmotic flow and heat transfer process driven by pressure difference in a simple microchannel, the results obtained are compared with the theoretical solution and the finite element method (FEMM), respectively, and the correctness of the method is verified. Micro mixing technology plays a key role in enhancing mass transfer and heat transfer in micro fluid control and transportation. It is of great significance for the miniaturization and integration of the equipment. In this paper, the electroosmotic micromixing and heat transfer under transverse and longitudinal electric field are simulated by changing the heterogeneity potential distribution structure of microchannel wall. The effects of pressure gradient and wall potential on the micromixing are analyzed. It is found that there are great differences in the micro-mixing flow states under the action of electric field in different directions, and the increase of pressure gradient will lead to the gradual weakening of the overall effect of electroosmotic mixing and heat transfer. Induction electroosmotic flow (EOF) is a new electrokinetic phenomenon which has been discovered and proposed in recent years. Compared with traditional electroosmotic flow (EOF), it can produce better driving effect on micro-fluid, but its internal law has not been fully understood, so it has high research value. In this paper, the eDPD method is applied to the study of electroosmotic flow and heat transfer induced by cylindrical electrode for the first time, and the induced electroosmotic flow and heat transfer characteristics are analyzed when the structure of electrode material changes under pressure difference. It is found that the structure of electrode material has a great influence on the flow state near the electrode. The electroosmotic eddy current induced by the left conductor material weakens the pressure gradient, while the right eddy current has a certain promoting effect on the pressure driven flow. The research in this paper enriches the theory of electrodynamics at mesoscopic scale and successfully applies the eDPD method to the study of coupled complex flow and heat transfer problems in multiple physical fields. The application field of the model is expanded and its reliability and flexibility are fully proved. It has laid a certain foundation for its development in the related direction.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類(lèi)號(hào)】：TK124
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本文編號(hào)：1880703