本文關(guān)鍵詞： 含蠟原油 流動剪切 紊流 層流 微觀特性　出處：《中國石油大學(華東)》2015年碩士論文　論文類型：學位論文

【摘要】：本文利用自主搭建的帶浮頂攪拌槽剪切系統(tǒng)和旋轉(zhuǎn)流變儀分別模擬紊流剪切和層流剪切,并通過數(shù)碼顯微成像系統(tǒng)觀測了剪切后原油蠟晶微觀結(jié)構(gòu),旨在揭示相同能量耗散率作用下,不同流場結(jié)構(gòu)的流動剪切對含蠟原油低溫流變性影響規(guī)律的差異,希望對建立更科學的室內(nèi)模擬熱油管道剪切歷史方法起到一定的指導作用。基于流場結(jié)構(gòu)相似的特點,采用攪拌槽模擬管道內(nèi)紊流流動,并設(shè)計了浮頂結(jié)構(gòu),有效地減少了剪切過程中原油輕組分的揮發(fā),討論了能量耗散率、剪切處理溫度、剪切時間等三個影響因素對膠凝原油屈服值和動平衡應力的影響規(guī)律;計算了攪拌槽內(nèi)流體的當量剪切速率,并在同軸圓筒流變儀中設(shè)定相同的實驗步驟以及剪切速率,以剪切處理溫度和能量耗散率為變量,對比兩種流態(tài)預剪切后的原油在低溫下觸變特性和膠凝特性差異規(guī)律,發(fā)現(xiàn)層流剪切后的油樣膠凝結(jié)構(gòu)更強,觸變特性較差。采用顯微鏡成像系統(tǒng)和圖形處理軟件分析了不同流態(tài)預剪切作用對含蠟原油蠟晶顆粒大小、形狀、分布等結(jié)構(gòu)特征的影響差異和微觀變化,綜合等積圓直徑、圓度、分析維數(shù)、特征空隙長度、顆粒總數(shù)等五個微觀參數(shù)解釋了不同流態(tài)預剪切對原油微觀蠟晶結(jié)構(gòu)的作用機理,以及造成原油宏觀低溫流變性差異的原因。從本文實驗結(jié)果看,單純以能量耗散率或當量剪切速率為模擬量,不同脈動強度的紊流摻混剪切效果存在較大的差異(認為層流是脈動強度為零的紊流),因此有必要從其對流體內(nèi)部分散相結(jié)構(gòu)的研究入手,在攪拌槽實驗裝置的基礎(chǔ)上,可以考慮引入紊流的渦旋尺度作為管流剪切歷史評價標準的補充,從而更科學合理地模擬管道剪切歷史。
[Abstract]:In this paper, turbulent shear and laminar shear were simulated by using the shear system of mixing tank with floating roof and rotary rheometer, respectively, and the microstructure of wax crystal after shearing was observed by digital microscopic imaging system. The purpose of this paper is to reveal the difference of the effect of flow shear of different flow field structures on the rheological properties of waxy crude oil at low temperature under the same energy dissipation rate. Based on the characteristics of similar flow field the turbulent flow in the pipe was simulated by mixing tank and the floating roof structure was designed. The volatilization of light components of crude oil in shear process is effectively reduced. The influence of three factors, such as energy dissipation rate, shear treatment temperature and shear time, on the yield value and dynamic equilibrium stress of cementitious crude oil are discussed. The equivalent shear rate of the fluid in the stirred tank is calculated, and the same experimental steps and shear rate are set in the coaxial cylinder rheometer. The shear treatment temperature and energy dissipation rate are taken as variables. Comparing the thixotropic characteristics and the gelling characteristics of the two kinds of pre-shearing crude oil at low temperature, it is found that the laminar flow shear oil sample has stronger cementing structure. Using microscope imaging system and graphic processing software, the influence of different flow state preshear on the size, shape and distribution of waxy crude wax grains was analyzed. Five microcosmic parameters, such as the diameter of equal product circle, roundness, analytical dimension, length of characteristic void and the total number of particles, are used to explain the mechanism of the effect of different flow state preshear on the microcrystalline structure of crude oil. According to the experimental results, the energy dissipation rate or equivalent shear rate is used as the simulation quantity. The shear effect of turbulent mixing with different pulsating intensity is quite different (it is considered that laminar flow is turbulent with zero pulsating intensity, so it is necessary to start with the study of the dispersed phase structure inside the fluid. On the basis of the experimental equipment of stirred tank, the vortex scale of turbulent flow can be considered as a supplement to the evaluation standard of shear history of pipe flow, so as to simulate the shear history of pipeline more scientifically and reasonably.
【學位授予單位】：中國石油大學(華東)
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TE832

【相似文獻】

相關(guān)期刊論文 前2條

1 張勁軍,嚴大凡;圓管內(nèi)湍流流動能量耗散率近似算法的可靠性分析[J];石油大學學報(自然科學版);2002年06期

2 李肇飛;;HY～130鋼能量耗散率特性的研究[J];青島建筑工程學院學報;1992年03期

相關(guān)會議論文 前3條

1 黃筑平;;塑性變形中的能量耗散率[A];中國力學學會學術(shù)大會'2005論文摘要集（下）[C];2005年

2 夏克青;倪睿;謝毅超;韋萍;;高分子添加物對熱湍流中能量級串的影響[A];中國力學大會——2013論文摘要集[C];2013年

3 王少可;孔夢桐;陳旭;牟海迪;劉陽洋;林鑒棠;;孤立波消波效率的實驗研究[A];第十三屆全國水動力學學術(shù)會議暨第二十六屆全國水動力學研討會論文集——D水動力學實驗和測試技術(shù)[C];2014年

相關(guān)碩士學位論文 前5條

1 王永博;三維湍流流動中的速度梯度統(tǒng)計研究[D];上海應用技術(shù)學院;2015年

2 姚劍;基于菌種存活率的固態(tài)發(fā)酵噴霧接種噴頭建模與優(yōu)化研究[D];南京林業(yè)大學;2015年

3 李炳鑫;管內(nèi)流動剪切對非牛頓原油作用規(guī)律及機理研究[D];中國石油大學(華東);2015年

4 王晗;一種用于研究培養(yǎng)細胞剪切耐受性裝置的設(shè)計、加工及應用研究[D];華東理工大學;2015年

5 劉鵬;油氣開采用井口低剪切節(jié)流閥的理論與實驗研究[D];北京化工大學;2014年

，

本文編號：1457805