【摘要】：攪拌設(shè)備因具有操作靈活、混合效果好、相接觸面積大和適用性強(qiáng)的優(yōu)點(diǎn)而廣泛用在機(jī)械、化工等過程工業(yè)中,是應(yīng)用最廣泛的化工單元操作之一。其中,攪拌槽內(nèi)部流場和固液懸浮特性的研究,對(duì)工業(yè)生產(chǎn)有重要意義,因此是國內(nèi)外學(xué)者研究的熱點(diǎn)內(nèi)容之一。近幾年來,攪拌反應(yīng)器的規(guī)模逐漸變大,相與相之間混合不均勻的問題也越來越明顯,并且當(dāng)前機(jī)械過程逐漸轉(zhuǎn)向“綠色”、節(jié)能方向,越來越看重產(chǎn)品回收率和產(chǎn)品質(zhì)量,因此合理設(shè)計(jì)和選擇攪拌設(shè)備就顯得特別重要。但如今對(duì)攪拌設(shè)備的選擇和設(shè)計(jì)仍然是主要依賴于小規(guī)模實(shí)驗(yàn)結(jié)果以及半理論和半經(jīng)驗(yàn)的方法,由于技術(shù)和條件的限制在設(shè)計(jì)中并不能清晰的了解攪拌槽內(nèi)部流場的詳細(xì)分布情況,而且對(duì)攪拌反應(yīng)器放大規(guī)律缺乏較深入的認(rèn)識(shí),實(shí)驗(yàn)?zāi)M周期長、偏差和花費(fèi)大。新的交叉學(xué)科計(jì)算流體力學(xué)技術(shù)為解決上述問題提供了新思路和新方法,其技術(shù)優(yōu)勢使得攪拌槽內(nèi)部流場及固液懸浮特性的數(shù)值模擬成為攪拌領(lǐng)域的研究熱點(diǎn)之一,但是攪拌槽內(nèi)部流場及固液懸浮特性的數(shù)值模擬還沒有形成較為完善的理論。本文以計(jì)算流體力學(xué)技術(shù)為主要研究手段,采用多重參考系法和標(biāo)準(zhǔn)κ—ε湍流模型對(duì)攪拌槽內(nèi)部流場及固液懸浮特性進(jìn)行了數(shù)值模擬,研究分析了攪拌轉(zhuǎn)速、槳離底間隙、固體顆粒濃度等因素對(duì)流場分布、固體顆粒濃度分布、臨界懸浮轉(zhuǎn)速和功率消耗的影響。 研究結(jié)果表明,槳葉離底間隙對(duì)攪拌槽內(nèi)流場及固液懸浮狀態(tài)影響很大,低離底間隙有利于槽內(nèi)固體顆粒的懸浮,但是當(dāng)離底間隙過低時(shí),功率消耗比較大,且槳葉離底間隙越低越容易出現(xiàn)清液層；增加攪拌轉(zhuǎn)速能夠改善攪拌效果,但是考慮到攪拌功率、耐久度等因素的影響,并不是攪拌轉(zhuǎn)速越大越好,需要綜合考慮來確定合適的攪拌轉(zhuǎn)速；槳離底間隙、固體顆粒直徑和固體體積濃度對(duì)攪拌功率均有影響,在相同條件下,功率消耗隨槳離底間隙的不同而不同,在C=T／4、T／5和T／6三種工況下,C=T／4時(shí)功率消耗最��；在相同條件下,功率消耗隨固體顆粒直徑的增大而增加；在同一攪拌轉(zhuǎn)速下,功率消耗隨固體體積濃度的減小而增加。
[Abstract]:Because of its advantages of flexible operation, good mixing effect, large contact area and strong applicability, mixing equipment is widely used in mechanical, chemical and other process industries, and is one of the most widely used chemical unit operations. Among them, the study of flow field and solid-liquid suspension characteristics in stirred tank is of great significance to industrial production, so it is one of the hot topics of domestic and foreign scholars. In recent years, the scale of stirred reactor has gradually become larger and the problem of uneven mixing between phases has become more and more obvious, and the current mechanical process is gradually turning to "green", energy-saving direction, and more emphasis on product recovery and product quality. Therefore, reasonable design and selection of mixing equipment is particularly important. But today, the selection and design of mixing equipment is still mainly dependent on small-scale experimental results and semi-theoretical and semi-empirical methods. Due to the limitation of technology and conditions, the detailed distribution of the flow field in the stirred tank can not be clearly understood in the design, and the detailed distribution of the flow field in the stirred tank is not well understood, and the experimental simulation period is long, the deviation and the cost are large. The new cross-disciplinary computational fluid dynamics (CFD) technology provides a new way of thinking and a new method to solve the above problems. Its technical advantages make the numerical simulation of the flow field and solid-liquid suspension characteristics in the stirred tank become one of the hot spots in the agitation field. However, the numerical simulation of the flow field and solid-liquid suspension characteristics in the stirred tank has not yet formed a more perfect theory. Based on computational fluid dynamics (CFD) technique, the flow field and solid liquid suspension characteristics in stirred tank are numerically simulated by means of multiple reference system method and standard 魏-蔚 turbulence model. The stirring speed and the bottom clearance of the impeller are studied and analyzed. The influence of factors such as solid particle concentration on flow field distribution, concentration distribution of solid particles, critical suspension speed and power consumption. The results show that the clearance of blade bottom has a great influence on the flow field and the solid liquid suspension state in the stirred tank. The low bottom gap is favorable to the suspension of solid particles in the tank, but when the gap is too low, the power consumption is relatively large. The lower the clearance from the bottom of the blade is, the easier it is to appear the liquid-clearing layer. Increasing the stirring speed can improve the stirring effect, but considering the influence of the stirring power and durability, it is not better to increase the stirring speed, so it is necessary to determine the appropriate stirring speed synthetically. The impeller bottom clearance, solid particle diameter and solid volume concentration have effects on the stirring power. Under the same conditions, the power consumption varies with the bottom clearance of the propeller. Under the three conditions of C / T / 4 / T / 5 and T / 6, The power consumption is minimum at C=T/ 4; Under the same conditions, the power consumption increases with the increase of solid particle diameter, and increases with the decrease of solid volume concentration at the same stirring speed.
【學(xué)位授予單位】：安徽理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TQ051.72

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 徐姚,張政,程學(xué)文,鄭玉貴,柯偉,姚治銘;旋轉(zhuǎn)圓盤上液固兩相流沖刷磨損數(shù)值模擬研究[J];北京化工大學(xué)學(xué)報(bào)(自然科學(xué)版);2002年03期

2 鐘麗,黃雄斌,賈志剛;固-液攪拌槽內(nèi)顆粒離底懸浮臨界轉(zhuǎn)速的CFD模擬[J];北京化工大學(xué)學(xué)報(bào)(自然科學(xué)版);2003年06期

3 李良超,張仲敏,黃雄斌;固液攪拌槽內(nèi)近壁區(qū)液相速度研究[J];北京化工大學(xué)學(xué)報(bào)(自然科學(xué)版);2005年01期

4 戴干策;范自暉;姚一平;;攪拌反應(yīng)器中湍流微結(jié)構(gòu)的研究[J];高�；瘜W(xué)工程學(xué)報(bào);1986年01期

5 黃雄斌，包雨云，施力田，王英琛;應(yīng)用電導(dǎo)探針測定固－液兩相流的局部速度[J];高�；瘜W(xué)工程學(xué)報(bào);1995年02期

6 黃正梁;王靖岱;陽永榮;;聲波的多尺度分解與攪拌釜中漿液濃度的測量[J];化工學(xué)報(bào);2006年09期

7 單賢根;禹耕之;楊超;毛在砂;杜令忠;張偉剛;;無擋板攪拌槽中液-固體系的分散特性[J];過程工程學(xué)報(bào);2008年01期

8 董厚生;魏化中;舒安慶;劉凱;;攪拌槽內(nèi)固液兩相流的數(shù)值模擬及功率計(jì)算[J];化工裝備技術(shù);2012年01期

9 馬慶勇;;漿液池?cái)嚢杵鞴桃簝上嗳S數(shù)值模擬[J];湖南農(nóng)機(jī);2010年07期

10 陳道芳;徐雷興;陳甘棠;戎順熙;;固、液系機(jī)械攪拌槽中顆粒懸浮特性的研究[J];化學(xué)反應(yīng)工程與工藝;1992年01期

相關(guān)博士學(xué)位論文 前1條

1 陳佳;側(cè)進(jìn)式攪拌反應(yīng)器內(nèi)均相及多相流體動(dòng)力學(xué)的數(shù)值研究[D];華東理工大學(xué);2013年

，

本文編號(hào)：2318589