本文選題：水力噴射空氣旋流器　切入點(diǎn)：氣相壓降特性　出處：《重慶理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：水力噴射空氣旋流器(water-sparged aerocyclone,WSA)是一種利用液相射流在氣相三維旋流場中的霧化現(xiàn)象,形成液體射流與氣體旋流耦合場,同時(shí)又利用旋流場的靜態(tài)超重力作用,實(shí)現(xiàn)強(qiáng)化氣液傳質(zhì)和反應(yīng)的新型傳質(zhì)反應(yīng)設(shè)備。為了深入認(rèn)識(shí)WSA中氣液兩相的作用機(jī)理,提出WSA中射流霧化的調(diào)控方法,本文采用實(shí)驗(yàn)研究,并結(jié)合數(shù)值模擬方法,系統(tǒng)地研究了WSA的氣相壓降特性與變化機(jī)制,以及WSA中射流霧化的傳質(zhì)面積與液滴尺寸。主要研究結(jié)論如下:1、WSA的氣相壓降隨著進(jìn)口氣速的增大,會(huì)相繼經(jīng)歷一個(gè)低壓降區(qū)、壓降突跳區(qū)和高壓降區(qū)三個(gè)特征區(qū)域,而且WSA中液體射流的排列方式不會(huì)影響這種氣相壓降變化的規(guī)律,射流的充分霧化發(fā)生在高壓降區(qū)域內(nèi)。2、雷諾應(yīng)力模型和VOF兩相流模型能夠較好地模擬WSA的氣相壓降特性和液相回流比。通過對(duì)三個(gè)不同氣相壓降區(qū)域的液相含率分布、射流流型的分析,提出了WSA氣相壓降突變的機(jī)理。在低壓降區(qū)域(0ug7.11 m·s-1),射流與旋流場的相互影響較小,射流保持較完整的形態(tài);在壓降突跳區(qū)域(7.11ug8.89 m·s-1),射流主要表現(xiàn)為袋式破碎霧化機(jī)理,射流表面的質(zhì)量被吹脫和袋式破碎霧化造成氣相密度突然增大,引起了氣相壓降的突跳;在高壓降區(qū)域(ug8.89 m·s-1),射流霧化逐漸轉(zhuǎn)化為剪切破碎霧化機(jī)理。3、在射流旋流耦合場中,軸向速度隨進(jìn)口氣速增大而增大。但當(dāng)進(jìn)口氣速處于壓降突跳區(qū)時(shí),在接近旋流器壁面處軸向速度增加最大;旋流場的切向速度出現(xiàn)下降,并發(fā)生方向逆轉(zhuǎn);耦合場徑向速度沿徑向分布不對(duì)稱性增大,速度方向也出現(xiàn)了逆轉(zhuǎn)現(xiàn)象。4、在氣相高壓降區(qū)域里,射流霧化的傳質(zhì)面積隨進(jìn)口氣速增大,先升高后下降,出現(xiàn)一個(gè)最大值。射流霧化傳質(zhì)面積較大時(shí),進(jìn)口氣速一般需要超過壓降突跳終點(diǎn)氣速的50%~100%,這與氣液兩相流數(shù)值模擬得到的結(jié)果范圍相近;射流霧化傳質(zhì)面積達(dá)到最大值時(shí),進(jìn)口氣速需超過壓降突跳終點(diǎn)氣速的80%左右。在一定的進(jìn)口速度下,隨著射流速度的增大,比傳質(zhì)面積也相應(yīng)地增大,而且當(dāng)射流速度由低速向高速變化的過程中,傳質(zhì)面積的增大在低射流速度時(shí)增加的幅度較明顯,在較高射流速度下傳質(zhì)面積增加較慢。5、WSA中液體射流在氣相高壓降區(qū)域中射流霧化的液滴尺寸,隨著進(jìn)口氣速的增大逐漸減小,達(dá)到最小值后又開始增大。射流霧化液滴尺寸達(dá)到最小值時(shí)的進(jìn)口氣速約在超過壓降突跳終點(diǎn)氣速的100%。這與傳質(zhì)面積較大的區(qū)域出現(xiàn)在進(jìn)口氣速超過壓降突跳終點(diǎn)氣速的50%~100%的結(jié)論相吻合。在一定的進(jìn)口氣速下,射流速度增大有使射流霧化最小液滴尺寸增大的趨勢(shì)。
[Abstract]:Jet air cyclone (water-sparged aerocyclone WSA) is a kind of phenomenon by liquid jet atomization in the gas phase in the formation of three-dimensional swirling flow, liquid jet and gas swirl coupling field, and using the super gravity field of static hydrocyclone, achieve new equipment to strengthen the gas-liquid mass transfer reaction mass transfer and reaction in order to effect. Understanding the mechanism of gas-liquid two-phase WSA, put forward the control method of WSA jet atomization, experimental study in this paper, combined with numerical simulation method, the system of WSA gas pressure drop characteristics and change mechanism, and the mass transfer area of WSA jet atomization and droplet size. The main conclusions are as follows: 1, with the inlet gas velocity increases WSA gas pressure drop, have experienced a low drop drop zone, jump three characteristics of regional area and pressure drop, and no liquid jet in the arrangement of the WSA A variation of the gas pressure drop, fully atomized jet high pressure drop occurred in the region of.2, the Reynolds stress model and VOF two-phase flow model can better simulate the WSA characteristics of gas pressure drop and liquid reflux ratio. The distribution rate of three different gas pressure drop zone liquid jet flow, analysis the flow pattern of the gas pressure drop, the mechanism of WSA mutation is proposed. In the low pressure drop region (0ug7.11 m s-1), the mutual influence small jet and swirling flow field of jet preserved form; jump region in the process pressure drop (7.11ug8.89 m s-1), mainly for the jet bag broken atomization mechanism, quality the jet surface is blowing and bag broken atomization caused by gas density increases suddenly, causing the gas pressure drop jump; pressure drop area (ug8.89 m s-1), jet atomization is gradually transformed into the shear atomization mechanism of.3, in the swirling coupling field, axial velocity. Gas velocity increases. But when the inlet gas velocity in the drop jump area, maximum increase near the cyclone wall axial velocity of swirling flow; the tangential velocity decreased and reversed direction; coupled radial velocity distribution along radial direction asymmetry increases, speed reversal phenomenon to the.4. In the gas phase pressure drop in the area and mass transfer area of jet atomization with inlet gas velocity increases, increased first and then decreased, there is a maximum value. The jet atomization mass transfer area is large, the inlet gas velocity generally requires more than drop jump end point gas velocity of 50%~ 100%, the gas-liquid two-phase flow numerical simulation results obtained range similar to jet atomization; mass transfer area reached the maximum value when the pressure drop around the inlet gas velocity required more than 80% jump end point gas velocity. At a certain inlet velocity, with the increase of jet velocity, ratio of mass transfer area is correspondingly increased, and When the jet velocity from low speed to high speed change, the increase in the mass transfer area of low jet velocity when the amplitude obviously increases slowly in.5 area of high jet velocity of mass transfer, droplet size, spray jet liquid jet WSA in the gas phase pressure drop in the region, with the increase of the inlet gas velocity gradually decreases, reaches a minimum value began to increase. The jet atomization droplet size reaches the minimum value when the inlet gas velocity is about over pressure drop jump end point gas velocity 100%. and the larger mass transfer area in the inlet gas velocity exceeds the pressure jump end point gas velocity 50%~100% is consistent with the conclusion. In a certain import the gas velocity, the jet velocity increases with the trend of the minimum jet atomization droplet size increases.

【學(xué)位授予單位】：重慶理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TQ051.8

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本文編號(hào)：1592717