發(fā)布時間：2018-08-12 07:27

【摘要】：納米制冷劑是在納米流體的概念上提出來的，他們之間主要區(qū)別就在于基液的不同，納米制冷劑采用的是氣化能力更強(qiáng)的制冷劑。我們按照一定的質(zhì)量分?jǐn)?shù)，將納米顆粒添加到制冷劑中，制備成新型、高效的換熱工質(zhì)。納米制冷劑的導(dǎo)熱系數(shù)高，而且其穩(wěn)定性好、對設(shè)備的磨損也小，這為開發(fā)適用于納米制冷劑的換熱器提出了新的方向�；�于此，本文研究了五種納米制冷劑的穩(wěn)定性，并分別這對五種納米制冷劑在三種不同類型的管內(nèi)進(jìn)行了沸騰換熱實(shí)驗(yàn)研究。 本文采用物理法和化學(xué)法相結(jié)合的方法制備納米制冷劑，將制備好的納米顆粒按照一定的比例添加到制冷劑中，然后添加表面分散劑，防止其產(chǎn)生團(tuán)聚的現(xiàn)象，然后利用超聲波振蕩使其形成穩(wěn)定的懸浮液。利用目測法和對比透射比法來評價納米制冷劑的穩(wěn)定性，發(fā)現(xiàn)當(dāng)濃度相同時，添加表面分散劑的納米制冷劑的穩(wěn)定性差別不大；而未添加表面分散劑的納米制冷劑的穩(wěn)定性很不好，穩(wěn)定性和密度成基本成反比。 納米制冷劑管內(nèi)流動沸騰換熱實(shí)驗(yàn)結(jié)果表明：同一質(zhì)量流量下，隨著納米顆粒質(zhì)量分?jǐn)?shù)的增加，，納米制冷劑的傳熱系數(shù)變大，增幅與納米顆粒的質(zhì)量分?jǐn)?shù)基本成線性關(guān)系；納米顆粒的質(zhì)量分?jǐn)?shù)是影響納米制冷劑強(qiáng)化傳熱性能的主要因素；不同納米顆粒對納米制冷劑的傳熱性能影響不一樣；納米顆粒本身熱導(dǎo)率大的，其制備成的納米制冷劑的強(qiáng)化傳熱性能更好一些；納米制冷劑的傳熱系數(shù)隨著干度的增大而增大。但干度在0.5和0.6之間時，納米制冷劑的傳熱系數(shù)增加的幅度最大。
[Abstract]:Nanometer refrigerant is put forward in the concept of nanometer fluid. The main difference between them lies in the difference of base liquid. The nanometer refrigerant uses refrigerant with stronger gasification ability. According to a certain mass fraction, the nanoparticles were added to the refrigerant to prepare a new and efficient heat transfer medium. The thermal conductivity of nano-refrigerant is high, and its stability is good, and the wear of the equipment is also small, which provides a new direction for the development of the heat exchanger suitable for nano-refrigerant. Based on this, the stability of five nanocrystalline refrigerants was studied, and the boiling heat transfer experiments of five nano-refrigerants in three different types of tubes were carried out. In this paper, nanometer refrigerants are prepared by combining physical and chemical methods. The prepared nanoparticles are added to the refrigerant in a certain proportion, and then surface dispersants are added to prevent the agglomeration. Then ultrasonic oscillation is used to form a stable suspension. The stability of nano-refrigerant was evaluated by visual method and contrast transmittance method. It was found that the stability of nano-refrigerant with surface dispersant was not different when the concentration was the same. However, the stability of nano-refrigerant without surface dispersant is very poor, and the stability is inversely proportional to the density. The experimental results of flow boiling heat transfer in nano-refrigerant tube show that the heat transfer coefficient of nano-refrigerant increases with the increase of mass fraction of nano-particles at the same mass flow rate, and the increase is basically linear with the mass fraction of nano-particles. The mass fraction of nanocrystalline particles is the main factor affecting the enhancement of heat transfer performance of nano-refrigerants; the effects of different nanoparticles on the heat transfer properties of nano-refrigerants are different; the thermal conductivity of nanocrystalline particles is large, The enhanced heat transfer performance of the prepared nano-refrigerant is better, and the heat transfer coefficient of the nano-refrigerant increases with the increase of dryness. However, when the dryness is between 0.5 and 0.6, the increase of the heat transfer coefficient of the nano-refrigerant is the largest.
【學(xué)位授予單位】：東北電力大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TB611

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 宣益民,李強(qiáng);納米流體強(qiáng)化傳熱研究[J];工程熱物理學(xué)報;2000年04期

2 畢勝山;史琳;;納米顆粒在制冷劑中的分散特性研究[J];工程熱物理學(xué)報;2007年02期

3 林成祥;陳穎;史保新;譚凱;;納米制冷劑在水平光管內(nèi)沸騰換熱的實(shí)驗(yàn)研究[J];廣東工業(yè)大學(xué)學(xué)報;2010年02期

4 孫斌;錢錚;;CuO/R141b納米制冷劑在管內(nèi)的流動沸騰傳熱特性[J];化工學(xué)報;2012年03期

5 朱冬生;李新芳;王先菊;李華;高進(jìn)偉;;氧化鋁-水納米流體的制備及其分散性研究[J];化工新型材料;2007年09期

6 畢勝山;史琳;王磊;;納米TiO_2顆粒在制冷工質(zhì)中的分散[J];過程工程學(xué)報;2007年03期

7 肖建軍;張宏偉;王蕾蕾;畢勝山;劉志剛;;納米添加劑在冰箱冷柜上節(jié)能研究[J];家電科技;2012年10期

8 陳宗淇;王世權(quán);;空位穩(wěn)定性理論[J];化學(xué)通報;1989年04期

9 莊大偉;彭浩;胡海濤;丁國良;朱禹;;含油金剛石納米制冷劑的核態(tài)池沸騰換熱特性[J];上海交通大學(xué)學(xué)報;2011年06期

10 謝華清;陳立飛;;納米流體對流換熱系數(shù)增大機(jī)理[J];物理學(xué)報;2009年04期

本文編號：2178329