本文選題：格子Boltzmann方法 + T型微混合器��； 參考：《東北大學(xué)》2012年碩士論文

【摘要】：微機電系統(tǒng)(micro electro mechanical systems, MEMS)是指基于集成電路工藝設(shè)計制造并集電子元件與機械器件于一體的微小系統(tǒng)。微混合器作為MEMS的重要組成部件,目前已越來越受到重視,對微尺度流動和液體混合的研究也變得越發(fā)重要。物理體系的研究方法可以分為理論研究,實驗研究和數(shù)值模擬三大類,隨著計算機技術(shù)的快速發(fā)展,數(shù)值模擬技術(shù)得到了越來越多的重視以及更廣泛的應(yīng)用。格子Boltzmann方法(LBM)作為一種全新的介觀模擬方法在近20年得到了快速的發(fā)展。LBM既可以分析不連續(xù)流場,又相對節(jié)約計算量的特點使其在模擬微流體流動和建模方面取得了重要進展。 本文基于LBM來對微混合器中流體的混合問題進行模擬。首先介紹了LBM的基礎(chǔ)理論,對Boltzmann方程進行了詳細的推導(dǎo),介紹了一些LBM的基本模型和邊界處理方法。然后,通過對流體力學(xué)中三個典型實例的仿真模擬驗證了LBM的可行性與準(zhǔn)確性,期間引入了混合指標(biāo)σ-來評價混合效果的好壞。最后將LBM應(yīng)用到微混合器流體混合的模擬中,對簡單T型微混合器和內(nèi)肋型微混合器進行了數(shù)值模擬,得出了不同的影響因素對混合效果的影響曲線。其中,對于簡單T型微混合器,有如下結(jié)論：入口速度越小,混合效果越好；混合通道寬度越小,混合效果越好,但混合指數(shù)的變化十分微��；碰撞系數(shù)越大,流體擴散越快,混合效果越好；粘度系數(shù)越大,混合效果越差。對于內(nèi)肋型微混合器,有：流體的混合效果隨著入口速度的減小呈現(xiàn)先變差后邊好的趨勢；碰撞系數(shù)對于高速條件下的混合幾乎沒有影響,對于低速條件下影響明顯；內(nèi)肋板的長度越大,流體的混合效果越好；周期長度越大,流體的混合效果越差,但混合指數(shù)的變化并不大。最后,本文對兩種微混合器在不同入口速度條件下的混合性能進行了對比,內(nèi)肋型微混合器要遠遠優(yōu)于簡單T型微混合器。
[Abstract]:Micro electro mechanical systems, MEMS) is a micro system based on integrated circuit process design and manufacture. As an important component of MEMS, micromixers have been paid more and more attention, and the study of micro-scale flow and liquid mixing has become more and more important. The research methods of physical system can be divided into three categories: theoretical research, experimental research and numerical simulation. With the rapid development of computer technology, numerical simulation technology has been paid more and more attention and widely used. As a new mesoscopic simulation method, lattice Boltzmann method has been developed rapidly in the past 20 years. LBM can not only analyze the non-continuous flow field, but also make important progress in simulating microfluid flow and modeling. In this paper, the fluid mixing problem in micro mixer is simulated based on LBM. Firstly, the basic theory of LBM is introduced, the Boltzmann equation is deduced in detail, and some basic models and boundary treatment methods of LBM are introduced. Then, the feasibility and accuracy of LBM are verified by the simulation of three typical examples in fluid mechanics, and the mixing index 蟽-is introduced to evaluate the mixing effect. Finally, the LBM is applied to the fluid mixing simulation of the micro mixer, and the numerical simulation of the simple T type micro mixer and the inner rib type micro mixer is carried out, and the influence curves of different factors on the mixing effect are obtained. For a simple T-type micromixer, the following conclusions are obtained: the smaller the inlet velocity, the better the mixing effect; the smaller the mixing channel width, the better the mixing effect, but the smaller the mixing exponent is, the faster the fluid diffuses, the greater the collision coefficient, the faster the fluid diffusion. The better the mixing effect is, the worse the mixing effect is with the increase of viscosity coefficient. For the inner ribbed micro mixer, the mixing effect of the fluid varies first and then better with the decrease of the inlet velocity, and the collision coefficient has little effect on the mixing at high speed and obvious effect on the mixing at low speed. The greater the length of the inner rib plate, the better the mixing effect of the fluid, and the worse the mixing effect of the fluid is with the increase of the period length, but the change of the mixing index is not great. Finally, the mixing performance of the two micromixers at different inlet velocities is compared. The inner rib micromixers are much better than the simple T-type micromixers.
【學(xué)位授予單位】：東北大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2012
【分類號】：TH-39

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本文編號：1945364