本文選題：熱敏物料　切入點：降液再沸器　出處：《天津大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：目前,在工業(yè)生產(chǎn)中熱敏物料的分離和純化方法主要是精餾,但熱敏物料的汽化裝置容易出現(xiàn)結(jié)焦、堵塞的現(xiàn)象。因此,本文提出一種新型再沸器-降液再沸器,并對降液再沸器內(nèi)流體分布不均勻問題和降液管內(nèi)強化傳熱問題進行了研究。首先,本文對降液再沸器流體分布不均勻性進行了實驗研究,考察了不同流量下,圓錐形導(dǎo)流件的結(jié)構(gòu)和位置對降液再沸器流體分布不均勻系數(shù)ξ的影響。實驗結(jié)果表明,當(dāng)降液式再沸器的封頭內(nèi)充滿液體時,在封頭內(nèi)加入適當(dāng)?shù)膱A錐形導(dǎo)流件有利于流體的均勻分布。在七種導(dǎo)流件中,當(dāng)導(dǎo)流件的圓錐角角度為120度、底邊直徑的大小為封頭內(nèi)徑的0.5倍、導(dǎo)流件頂端距離封頭進液管管口的豎直高度為封頭總高度的0.1倍時,導(dǎo)流件的導(dǎo)流效果較好,此時各個流量下降液管內(nèi)分布不均勻系數(shù)ξ減小了54%~69%,(qi-q)max/q的最大值為3.21%,壓降增大了4.3%~16.7%。其次,為了研究降液管內(nèi)的強化傳熱,本文通過FLUENT建立了內(nèi)置連續(xù)扭帶和間斷扭帶的降液管模型,模擬了單管內(nèi)流動和傳熱特性,考察了內(nèi)置不同扭帶時管內(nèi)傳熱的努賽爾準數(shù)、阻力因子和傳熱效果綜合評價因子(PEC)的變化。由模擬結(jié)果可知,當(dāng)以水為工作介質(zhì)并且降液管管內(nèi)雷諾數(shù)在9952~59712之間時,連續(xù)扭帶管與光滑管相比管內(nèi)傳熱系數(shù)和阻力系數(shù)均增大,但是PEC均小于1。導(dǎo)致這種現(xiàn)象的根本原因是流動阻力過大。因此,減小阻力系數(shù)可以提高內(nèi)置連續(xù)扭帶降液管管內(nèi)流體的綜合傳熱效果。與連續(xù)扭帶相比,內(nèi)置間斷扭帶的降液管管內(nèi)傳熱系數(shù)和阻力均有所減小,但是傳熱綜合效果評價指標PEC均增大。當(dāng)間斷扭帶的間斷距離為節(jié)距的2倍時,管內(nèi)傳熱的PEC為1.05~1.33,有效地提高了綜合傳熱效果。
[Abstract]:At present, distillation is the main method of separation and purification of thermosensitive materials in industrial production, but the vaporization device of thermosensitive materials is prone to coking and clogging. Therefore, a new type of reboiler, down-liquid reboiler, is proposed in this paper. The non-uniformity of fluid distribution in down-flow reboiler and the problem of enhanced heat transfer in down-flow tube are studied. Firstly, the non-uniformity of fluid distribution in down-flow reboiler is studied experimentally, and the different flow rates are investigated. The influence of the structure and position of the conical diversion on the non-uniform coefficient of fluid distribution in the down-flow reboiler is obtained. The experimental results show that when the head of the down-flow reboiler is filled with liquid, The addition of a proper conical diversion to the head is beneficial to the uniform distribution of the fluid. In the seven types of diversion, when the conical angle of the diversion is 120 degrees, the diameter of the bottom edge is 0.5 times the inner diameter of the head. When the vertical height of the top of the diversion piece is 0.1 times of the total height of the head, the diversion effect of the diversion piece is better. At this point, the non-uniform distribution coefficient 尉 of each flow drop fluid pipe decreases the maximum value of 54qi-qi-qnx / Q to 3.21, and the pressure drop increases by 4.3% 16.7. Secondly, in order to study the enhanced heat transfer in the down-flow tube, the maximum value is 3.21, and the pressure drop increases by 4.3% to 16.7.The second, in order to study the enhanced heat transfer in the downflow tube, In this paper, a down-flow tube model with continuous and discontinuous torsion bands is established by FLUENT. The flow and heat transfer characteristics in a single tube are simulated, and the Nussel number of heat transfer in a tube with different torsion bands is investigated. The variation of drag factor and heat transfer effect evaluation factor (PECs). The simulation results show that when water is used as the working medium and the Reynolds number in the downflow pipe is between 9952 and 59712, Compared with the smooth tube, the heat transfer coefficient and the resistance coefficient of the continuous torsion tube are increased, but the PEC is less than 1. The fundamental reason for this phenomenon is that the flow resistance is too large. Reducing the resistance coefficient can improve the comprehensive heat transfer effect of the fluid in the down-flow tube of the built-in continuous torsion band. Compared with the continuous torsion strip, the heat transfer coefficient and resistance in the down-flow tube with the built-in discontinuous torsion belt are reduced. When the discontinuous distance is 2 times of the pitch distance, the PEC of heat transfer in the tube is 1.05N 1.33, which effectively improves the comprehensive heat transfer effect.
【學(xué)位授予單位】：天津大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TQ051.65

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