本文選題：納米多孔 + 強(qiáng)化沸騰��； 參考：《華南理工大學(xué)》2015年碩士論文

【摘要】：納米多孔結(jié)構(gòu)通過(guò)有效的增大傳熱面積、改善表面潤(rùn)濕性能、保持優(yōu)異熱傳導(dǎo)率、以及提高潛在汽化核心密度,可顯著提高沸騰傳熱性能。其在強(qiáng)化沸騰方面具有廣闊的應(yīng)用前景。強(qiáng)化沸騰由于能大幅度提高能源利用率和解決高熱流密度元器件散熱問(wèn)題,在熱能動(dòng)力、新能源、核電、石油化工等傳統(tǒng)工業(yè)領(lǐng)域以及微電子散熱等高新技術(shù)領(lǐng)域得到了廣泛的應(yīng)用。本文采用了一種新型電鍍/熱處理/脫合金組合工藝路線進(jìn)行納米多孔表面制備。通過(guò)選擇恰當(dāng)制備參數(shù)可獲得具有單一成分、均勻三維連續(xù)孔隙結(jié)構(gòu)、以及良好潤(rùn)濕性能的納米多孔表面。熱處理參數(shù),脫合金溶液,脫合金時(shí)長(zhǎng)等制備參數(shù)對(duì)納米多孔銅表面特性產(chǎn)生重要影響。本文主要探討了對(duì)表面形貌、化學(xué)成分和表面潤(rùn)濕性等表面特性的影響。本文設(shè)計(jì)并搭建了飽和池沸騰測(cè)試系統(tǒng),利用高速攝影技術(shù)進(jìn)行了可視化研究,對(duì)比了不同熱流密度下納米多孔表面與光滑表面的汽泡動(dòng)力學(xué)特征差異。在低熱流密度階段,納米多孔表面與光滑表面汽泡動(dòng)力學(xué)特征差異包括:出現(xiàn)過(guò)冷沸騰現(xiàn)象,飽和沸騰階段提前,汽泡數(shù)量增多,汽泡直徑減小,汽泡生長(zhǎng)脫離頻率增加,大量汽泡形成汽柱。在高熱流密度階段,納米多孔表面能延緩汽塊以及大汽泡的生成。從沸騰傳熱系數(shù)和臨界熱流密度的角度研究了納米多孔銅表面沸騰傳熱性能。與光滑表面相比,納米多孔表面具有顯著強(qiáng)化沸騰性能效果,并能有效提高臨界熱流密度。納米多孔表面的表面形貌,表面成分和表面潤(rùn)濕性能等表面特性對(duì)其沸騰傳熱性能有著重要影響。結(jié)合納米多孔表面與光滑表面在汽泡動(dòng)力學(xué)特征、表面特性和沸騰換熱性能方面的差異,對(duì)納米多孔結(jié)構(gòu)強(qiáng)化沸騰傳熱機(jī)理進(jìn)行分析。在飽和池沸騰環(huán)境中,長(zhǎng)期處于核態(tài)沸騰階段的納米多孔銅能保持良好化學(xué)穩(wěn)定性且其微觀形貌會(huì)發(fā)生自相似演化。最后,利用電鍍鋅/熱擴(kuò)散/脫合金組合工藝路線的易操作性,制備了微納米復(fù)合結(jié)構(gòu)表面。池沸騰測(cè)試結(jié)果顯示:微納米復(fù)合結(jié)構(gòu)表面結(jié)合了微槽道結(jié)構(gòu)和納米多孔結(jié)構(gòu)這兩種強(qiáng)化結(jié)構(gòu)的優(yōu)勢(shì),進(jìn)一步增大了沸騰傳熱系數(shù)和臨界熱流密度。
[Abstract]:By effectively increasing the heat transfer area, improving the surface wettability, maintaining excellent heat conductivity and increasing the potential vaporization core density, the boiling heat transfer performance of nano-porous structure can be improved significantly. It has broad application prospect in strengthening boiling. Enhanced boiling can greatly improve energy efficiency and solve heat dissipation problems of components with high heat flux, in thermal power, new energy, nuclear power, Traditional industries such as petrochemical industry and high-tech fields such as micro-electronic heat dissipation have been widely used. In this paper, a new electroplating / heat treatment / dealloying process was used to prepare nano porous surface. By choosing the appropriate preparation parameters, the nano-porous surface with single composition, uniform three-dimensional continuous pore structure and good wettability can be obtained. The preparation parameters, such as heat treatment parameters, dealloying solution and dealloying time, have an important effect on the surface characteristics of nano-porous copper. In this paper, the effects on surface morphology, chemical composition and wettability are discussed. In this paper, a saturated pool boiling measurement system was designed and constructed. The visualization study was carried out by high speed photography, and the differences of bubble dynamics between nano-porous surface and smooth surface at different heat flux were compared. At the stage of low heat flux, the differences of bubble dynamics between nano-porous surface and smooth surface include the phenomenon of supercooled boiling, the advance of saturated boiling stage, the increase of bubble number, the decrease of bubble diameter and the increase of bubble growth detaching frequency. A large number of bubbles form columns of steam. At the stage of high heat flux, nano-porous surfaces can delay the formation of steam blocks and large bubbles. The boiling heat transfer performance of nano-porous copper surface was studied from the point of view of boiling heat transfer coefficient and critical heat flux. Compared with the smooth surface, the nano-porous surface has obvious enhancement effect on boiling performance and can effectively increase the critical heat flux. The surface morphology, surface composition and wettability of nano-porous surface have an important effect on the boiling heat transfer performance. Based on the differences of bubble dynamics, surface characteristics and boiling heat transfer properties between nano-porous surface and smooth surface, the mechanism of enhancement of boiling heat transfer by nano-porous structure was analyzed. In the saturated pool boiling environment, the nano-porous copper in the nucleated boiling phase can maintain good chemical stability and its microscopic morphology will evolve from the same. Finally, the micro-nano composite structure surface was prepared by the easy operation of zinc electroplating / thermal diffusion / dealloying process. The results of pool boiling test show that the surface of micro-nanocomposite structure combines the advantages of micro-channel structure and nano-porous structure, and further increases the boiling heat transfer coefficient and critical heat flux.
【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB383.1;O614.121

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本文編號(hào)：2080375