發(fā)布時(shí)間：2018-08-03 07:44

【摘要】：隨著電子產(chǎn)品的發(fā)展,芯片集成化程度越來(lái)越高,在微米級(jí)尺度上對(duì)芯片進(jìn)行散熱是極具挑戰(zhàn)性的課題。高效導(dǎo)熱薄膜材料為芯片散熱問(wèn)題的解決提供了新思路。近年來(lái),采用納米流體的靜電霧化沉積制備高效導(dǎo)熱薄膜材料逐漸引起了國(guó)內(nèi)外學(xué)者的關(guān)注。納米流體因其自身物理性質(zhì)的特異性,其靜電霧化特性區(qū)別于普通流體,深入了解納米流體靜電霧化特性并探索其破碎機(jī)制可為發(fā)展高效薄膜制備技術(shù)奠定理論基礎(chǔ)。基于此,本文對(duì)納米流體的靜電霧化特性進(jìn)行了基礎(chǔ)性的實(shí)驗(yàn)研究,主要工作如下:采用顯微高速數(shù)碼攝像技術(shù)對(duì)納米流體的靜電霧化模式轉(zhuǎn)變進(jìn)行了可視化研究。以不同組份的納米流體為研究介質(zhì),精確捕捉了不同工況下納米流體霧化形態(tài)的演變行為;探索了質(zhì)量分?jǐn)?shù)及流量等因素對(duì)納米流體霧化模式轉(zhuǎn)變的影響。實(shí)驗(yàn)結(jié)果表明:隨著質(zhì)量分?jǐn)?shù)的升高,納米流體的錐射流模式區(qū)間逐漸縮小,過(guò)渡到錐射流狀態(tài)的臨界電場(chǎng)強(qiáng)度逐漸增大,而電導(dǎo)率的升高使得納米流體更易過(guò)渡到多股射流模式。流量的增加削弱了霧化的穩(wěn)定性,形成錐射流及多股射流所需的電場(chǎng)強(qiáng)度越高。繪制了電場(chǎng)強(qiáng)度和流量影響下特定組份納米流體的霧化模式圖,為探索和發(fā)展薄膜材料的制備技術(shù)奠定了基礎(chǔ)。基于納米流體靜電霧化模式的轉(zhuǎn)變規(guī)律,對(duì)各霧化模式下的液滴沉積分布特性進(jìn)行了實(shí)驗(yàn)研究。實(shí)驗(yàn)結(jié)果表明:隨著電壓的增大,液滴粒徑呈減小趨勢(shì),滴狀模式下液滴粒徑呈指數(shù)減小;錐射流模式下液滴粒徑呈線性減小;多股射流模式下液滴粒徑變化較為復(fù)雜。流量的降低可使液滴粒徑有所減小,但液滴粒徑減小并不明顯;流量降低后,液滴粒徑分布較寬,小粒徑液滴所占比例有所升高。對(duì)不同組份納米流體荷電液滴在氣動(dòng)作用下的變形破碎特性進(jìn)行了實(shí)驗(yàn)研究。結(jié)果表明:荷電液滴袋狀破碎過(guò)程;中隨著納米顆粒質(zhì)量分?jǐn)?shù)的增加,荷電液滴袋的生長(zhǎng)及袋的破碎所需時(shí)間逐漸減少;高荷電量的乙醇液滴與低荷電量的石墨-乙醇納米流體液滴在破碎過(guò)程中,破碎所需時(shí)間以及形態(tài)都極其類似,這表明納米顆粒的加入促進(jìn)了氣動(dòng)作用下荷電液滴袋狀破碎的進(jìn)程。
[Abstract]:With the development of electronic products, the integration of chips is becoming more and more high. High-efficiency thermal conductive thin-film materials provide a new way to solve the problem of chip heat dissipation. In recent years, the preparation of high efficiency thermal conductivity thin films by electrostatic atomization deposition of nanofluids has gradually attracted the attention of scholars at home and abroad. The electrostatic atomization property of nano-fluid is different from that of ordinary fluid because of its own specific physical properties. Understanding the electrostatic atomization characteristics of nano-fluid and exploring its crusher can lay a theoretical foundation for the development of high-efficiency thin film preparation technology. Based on this, the basic experimental study of electrostatic atomization characteristics of nano-fluid is carried out in this paper. The main work is as follows: the visualization study of electrostatic atomization mode transformation of nano-fluid is carried out by using micro-high-speed digital camera technology. The evolution behavior of nano-fluid atomization morphology under different working conditions was accurately captured with different components of nano-fluid as the research medium, and the effects of mass fraction and flow rate on the transformation of nano-fluid atomization mode were explored. The experimental results show that with the increase of mass fraction, the range of conical jet mode of nano-fluid gradually decreases, and the critical electric field intensity of transition to cone-jet state increases gradually. The increase of conductivity makes it easier for nanoscale fluid to transition to multi-strand jet mode. With the increase of flow rate, the stability of atomization is weakened, and the electric field intensity required for the formation of conical jet and multi-jet is higher. The atomization mode diagram of nano-fluids with specific components under the influence of electric field intensity and flow rate was drawn, which laid a foundation for exploring and developing the preparation technology of thin film materials. Based on the transformation rule of electrostatic atomization mode of nano-fluid, the deposition distribution characteristics of droplets in different atomization modes were studied experimentally. The experimental results show that the droplet size decreases with the increase of voltage, decreases exponentially in droplet mode, linearly decreases in cone-jet mode, and complex in multi-strand jet mode. When the flow rate decreases, the droplet size decreases, but the droplet size decreases not obviously. After the flow rate decreases, the droplet size distribution is wider, and the ratio of small droplet size increases. The characteristics of deformation and breakage of charged droplets with different components under aerodynamic action were investigated experimentally. The results show that the growth of charged droplet bags and the time required to break them decrease with the increase of the mass fraction of nanoparticles. The breakage time and morphology of high-charge ethanol droplets and low-charge graphite-ethanol nano-fluid droplets are very similar. This indicates that the addition of nanoparticles promotes the process of charged droplet bag breakage under pneumatic action.
【學(xué)位授予單位】：江蘇大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB383.1

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本文編號(hào)：2161074