本文選題：偏心攪拌 + 偏心率��； 參考：《北京化工大學》2015年碩士論文

【摘要】：在攪拌混合過程中,常常需要用到擋板來強化混合效果,但在某些特定的反應槽設計中,考慮到特殊槽體材質、物料等的特殊性,導致在設備內部添加擋板反而對生產不利,偏心攪拌技術能夠很好的解決這一問題,此外在一些如表面加料促進粉體快速分散和結晶反應器內減少晶體的二次成核等工藝時,偏心攪拌能達到比中心全擋板更好的效果。本文通過實驗以及數值模擬,研究了偏心攪拌時偏心率、轉速、槳的安裝高度等因素對槳功耗、漩渦特性、混合時間及上浮顆粒均勻下拉轉速和臨界懸浮轉速等的影響,得出如下結論：(1)偏心攪拌功率消耗隨偏心率的增大會先增大后減小,在偏心率為e=0.4時功率消耗和功率準數最大,最大功率準數比全擋板時高28%左右；(2)偏心攪拌內會產生漩渦,其中心隨著偏心率的增加沿特定路線運動,在偏心率為0.45兩側分別各自沿近似直線運動,且恒定轉速時,漩渦深度隨偏心率增大按線性規(guī)律減�。晦D速增大時,漩渦深度也隨之增大,增幅程度隨偏心率增大而減弱；(3)在偏心率介于0～0.45時上浮顆粒均勻下拉轉速隨偏心率增大而減小,偏心率介于0.45-0.6時隨偏心率增大而增大；(4)偏心攪拌槳葉區(qū)吸氣轉速隨偏心率增大先降低后增高,在偏心率為0.3左右時達到最低,吸入氣體在偏心率小于0.2時主要分散在攪拌槳以上區(qū)域而偏心率超過0.2后逐漸分散到攪拌槳下方區(qū)域；(5)偏心攪拌混合時間隨偏心率的增大呈先減小后增大趨勢,偏心率為0.45時為拐點,此時混合時間準數較全擋板時減小20%左右；(6)固液懸浮時臨界懸浮轉速均比中心全擋板時高,且隨偏心率增大會先增大后減小,在偏心率為0.35時臨界懸浮轉速達到最大,最大約為全擋板條件下的1.4倍。
[Abstract]:In the mixing process, the baffle is often used to strengthen the mixing effect, but in the design of some specific reaction tanks, considering the particularity of the special tank material and material, it is harmful to the production to add the baffle inside the equipment. Eccentricity stirring technology can solve this problem very well. In addition, in some processes such as surface feeding to promote the rapid dispersion of powder and the reduction of secondary nucleation of crystals in the crystallization reactor, eccentric stirring can achieve better results than the central full baffle. In this paper, the effects of eccentricity, rotational speed and installation height on the power consumption, swirl characteristics, mixing time, uniform pull-down speed and critical suspension speed of the propeller during eccentric stirring are studied through experiments and numerical simulation. The conclusion is as follows: (1) the power consumption of eccentric mixing increases first and then decreases with the increase of eccentricity. When the eccentricity ratio is 0.4, the power consumption and power criterion is the largest, and the maximum power criterion is about 28% higher than that of the full baffle. With the increase of eccentricity, the center of the vortex moves along a certain route. When the eccentricity is 0.45, the swirl depth decreases linearly with the increase of eccentricity, and when the eccentricity is 0.45, the vortex depth decreases linearly with the increase of eccentricity. The depth of swirl increases, and the increasing degree decreases with the increase of eccentricity.) when the eccentricity is between 0 and 0.45, the uniform pull-down speed of floating particles decreases with the increase of eccentricity. When the eccentricity ratio is between 0.45-0.6, it increases with the increase of eccentricity.) the suction speed in the eccentrically stirred blade region decreases first and then increases with the increase of eccentricity, and reaches the lowest when the eccentricity ratio is about 0.3. When the eccentricity ratio is less than 0.2, the suction gas is mainly dispersed in the area above the impeller, but the eccentricity ratio is more than 0.2 and gradually dispersed to the area below the impeller.) the mixing time of eccentric mixing decreases first and then increases with the increase of eccentricity. When the eccentricity is 0.45, the number of mixing time datum is 20% less than that of full baffle.) the critical suspension speed of solid liquid suspension is higher than that of center full baffle, and with the increase of eccentricity, the critical suspension speed will first increase and then decrease. When the eccentricity is 0.35, the critical suspension speed reaches the maximum, and the maximum is about 1.4 times of that under the condition of full baffle.
【學位授予單位】：北京化工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ027.2

【參考文獻】

相關期刊論文 前1條

1 王嘉駿;顧雪萍;馮連芳;曹松峰;胡國華;;臥式攪拌槽內流體混合的實驗與模擬研究[J];中國科技論文在線;2008年12期

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本文編號：1947316