本文關(guān)鍵詞： 橫管降膜流動(dòng) 結(jié)構(gòu)參數(shù) 流動(dòng)特性 液膜分布 數(shù)值模擬　出處：《大連理工大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：橫管降膜蒸發(fā)冷卻技術(shù)因其在傳熱效率、抗管壁結(jié)垢和易于排出不凝氣體等方面具有的顯著優(yōu)勢,加之其能充分利用工業(yè)余熱和低品位熱能,己被廣泛應(yīng)用于大型工業(yè)生產(chǎn)和國民生活中,是解決能源消耗過大、排放物污染嚴(yán)重等問題的一種高效能技術(shù)。橫管管外的液體降膜流動(dòng)和蒸發(fā)冷凝是一個(gè)復(fù)雜的多相流動(dòng)與傳熱傳質(zhì)過程,管外液膜可以看作傳熱傳質(zhì)發(fā)生的載體,其管間流動(dòng)型態(tài)、流體間的相互作用和管外液膜的厚度及分布規(guī)律等,都直接影響了整個(gè)管束的傳熱傳質(zhì)情況。本文以海水淡化應(yīng)用中的橫管降膜蒸發(fā)技術(shù)為背景,借助Fluent軟件,采用VOF方法對橫管管外的液體流動(dòng)特性和液膜的鋪展分布情況進(jìn)行了數(shù)值模擬研究,以豐富對橫管降膜流動(dòng)中液體在多種因素耦合作用下的動(dòng)力學(xué)規(guī)律的研究。本文在閱讀了大量相關(guān)文獻(xiàn)的基礎(chǔ)上,針對影響管液體成膜的結(jié)構(gòu)參數(shù),對橫管降膜的流動(dòng)特性和液膜分布進(jìn)行了較為全面的二維數(shù)值模擬,研究了噴淋密度、管間距、入口Re數(shù)和管徑大小等不同參數(shù)下的液膜厚度變化規(guī)律,并找出其中影響液膜分布的最主要因素,為三維數(shù)值模擬提供一定的參考依據(jù)。二維模擬在研究膜狀流型時(shí)能夠獲得較好的規(guī)律,但不能觀察到柱狀流型下液膜沿軸向鋪展的流動(dòng)行為。鑒于此,本文重點(diǎn)針對柱狀流型下的橫管降膜流動(dòng)過程進(jìn)行了全三維數(shù)值模擬,對液體沿橫管軸向的鋪展情況和液膜在管外的分布情況進(jìn)行了細(xì)致分析。此外,在確定穩(wěn)定柱狀流型的過程中,本文是以滴柱狀過渡流態(tài)為臨界,并對這種滴狀和柱狀?yuàn)A雜出現(xiàn)的管間流型下的液膜流動(dòng)、鋪展規(guī)律進(jìn)行了動(dòng)力學(xué)分析。通過對橫管降膜流動(dòng)的模擬研究發(fā)現(xiàn),液體在管外鋪展成膜的情況受到各種外力的疊加作用和液體間的相互作用,液膜沿圓周方向的分布呈現(xiàn)規(guī)律性的波動(dòng)變化。本文的三維數(shù)值模擬結(jié)果能較好的解釋和分析液體的流動(dòng)特性和成膜規(guī)律。單噴淋口下液體會(huì)在管外鋪展形成“馬鞍形”；當(dāng)液體分別從相鄰兩噴淋口噴出時(shí),兩側(cè)下落液體形成的液膜會(huì)沿著軸向交匯融合,并在中間位置形成波峰,液體間的相互作用力使得越靠近波峰位置的液膜厚度越大,兩側(cè)液體最終在中間位置附近匯成一個(gè)新的液柱并流向下一級管束。相比之下,二維模擬在研究膜狀流的液膜流動(dòng)和分布規(guī)律時(shí)能給出較好的解釋,但不能獲得軸向的液膜鋪展和流動(dòng)特性。此外,二維模擬在分析和篩選多種結(jié)構(gòu)參數(shù)的影響規(guī)律時(shí)發(fā)揮了高效作用,并為三維模擬提供了重要的參考依據(jù)。
[Abstract]:Horizontal tube falling film evaporation cooling technology because of its significant advantages in heat transfer efficiency, anti wall fouling and easy discharge of noncondensable gas and other aspects of the full utilization of industrial waste heat and low grade heat energy, has been widely used in large-scale industrial production and national life, is to solve the problem of energy consumption is too large, a efficient technical problems of emissions pollution. Horizontal tube falling film flow and evaporation condensation is a complex multiphase flow and heat transfer process of liquid film can be regarded as the carrier of mass transfer occurs, the inter tube flow pattern, the interaction between fluid and liquid film thickness and distribution, have a direct impact on the heat and mass transfer. The whole bundle of seawater desalination in the application of horizontal tube falling film evaporation technology as the background, with the help of Fluent software, using VOF method of liquid flow on transverse tube. The distribution and spreading of liquid membrane were studied by numerical simulation, study on the kinetics of liquid tube falling film flow in under coupling action of various factors on the cross to the rich. Based on the basis of reading a lot of literature, the influence of structure parameters for liquid film, liquid film on the flow and distribution of horizontal tube the falling film of two dimensional numerical simulation of a comprehensive study, the spray density, tube spacing, film thickness variation of different parameters of Re entrance number and tube size and under, and find out where the main factors affecting the film distribution, and to provide reference for numerical simulation. The two-dimensional simulation can obtain better regularity in the study of film flow, but cannot observe the flow behavior of liquid film flow along the axial direction of columnar spreading. In view of this, this paper focuses on horizontal tube falling film flow process of columnar regime The three-dimensional numerical simulation, the distribution of the liquid along the horizontal tube axial spreading and liquid film outside the pipe is analyzed in detail. In addition, in the process of determining the stability of columnar patterns, this paper is based on the drop column transition regime is critical, and the mixed liquid flow tube clamp between flow patterns under the the droplet and column, spreading rule of the dynamic analysis. Through simulation research on horizontal tube falling film flow that liquid by the interaction of various forces between superposition and liquid in the tube spreading film, fluctuation of film distribution along the circumferential direction of the three-dimensional numerical. The simulation results of this paper can better explain and analyze the flow characteristics of liquid film and liquid spray mouth under the law. A single experience outside the pipe spreading form "saddle"; when the liquid is ejected from the spray port two adjacent respectively, on both sides of The liquid falling liquid film formed along the axial convergence, and peak is formed in the middle position, the interaction between the liquid film thickness is close to the peak position of the liquid in the middle position, both sides end near the sink into a new liquid column and flow to the next level bundle. In contrast, the two-dimensional simulation of liquid flow and Study on the distribution in the film flows can give a better explanation, but can not get the film spreading axial and flow characteristics. In addition, the two-dimensional simulation plays a role in the efficient effect of different structure parameters and screening analysis, and provides an important reference for three-dimensional simulation.

【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：TK124

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 馬學(xué)虎;蘭忠;溫榮福;彭本利;徐威;朱霞;閻雪峰;江紅;王永長;閆萍;;低溫多效蒸發(fā)海水淡化系統(tǒng)性能的實(shí)驗(yàn)研究[J];高�；瘜W(xué)工程學(xué)報(bào);2014年06期

2 沈勝強(qiáng);陳學(xué);牟興森;王耀萱;高宏達(dá);;管間距對水平管降膜蒸發(fā)流動(dòng)形態(tài)和傳熱的影響[J];哈爾濱工程大學(xué)學(xué)報(bào);2014年12期

3 路作龍;那威;李德英;宋艷;;小溫差下水平橢圓管外表面淋激換熱特性實(shí)驗(yàn)研究[J];區(qū)域供熱;2014年03期

4 羅林聰;潘繼紅;田茂誠;黃濤;任毓程;;管形對水平管降膜圓周膜厚和Nusselt數(shù)的影響[J];化工學(xué)報(bào);2013年08期

5 羅林聰;張冠敏;潘繼紅;田茂誠;;Flow and heat transfer characteristics of falling water film on horizontal circular and non-circular cylinders[J];Journal of Hydrodynamics;2013年03期

6 侯昊;畢勤成;馬紅;;水平管降膜厚度分布特性及對傳熱的影響[J];西南交通大學(xué)學(xué)報(bào);2011年06期

7 雷賢良;李會(huì)雄;顏利波;郭斌;;氣流作用下水平管外液柱偏移特性的數(shù)值模擬研究[J];工程熱物理學(xué)報(bào);2010年11期

8 王小飛;何茂剛;張穎;;水平管降膜蒸發(fā)器管外液體流動(dòng)數(shù)值模擬[J];工程熱物理學(xué)報(bào);2008年08期

9 何茂剛;王小飛;張穎;費(fèi)繼友;;水平管降膜蒸發(fā)器管外液體流動(dòng)研究及膜厚的模擬計(jì)算[J];熱科學(xué)與技術(shù);2007年04期

10 馬學(xué)虎,高大志,安家明,朱曉波,陳嘉賓,鄧新祿;功能表面降膜蒸發(fā)傳熱特性的實(shí)驗(yàn)研究[J];熱科學(xué)與技術(shù);2003年02期

相關(guān)碩士學(xué)位論文 前1條

1 陳敬東;水平管降膜流動(dòng)形態(tài)的數(shù)值模擬與實(shí)驗(yàn)研究[D];北京建筑大學(xué);2014年

，

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