本文關(guān)鍵詞：填充床內(nèi)顆粒物料流動的實驗和數(shù)學模型研究　出處：《重慶大學》2015年碩士論文　論文類型：學位論文

  更多相關(guān)文章： 填充床 顆粒物料流動 連續(xù)介質(zhì)模型 數(shù)值計算

【摘要】：顆粒流動是材料制備工藝中比較普遍的現(xiàn)象,如稀土氧化物制備、鋼鐵材料制備的高爐、豎爐工藝等。豎爐內(nèi)顆粒物料的流動現(xiàn)象與豎爐的操作性能、生產(chǎn)效率和產(chǎn)品質(zhì)量密切相關(guān),掌握填充床中物料的流動規(guī)律對認識反應(yīng)器的特性、進行反應(yīng)器操作和控制非常重要。研究室溫裝置內(nèi)顆粒物料流動規(guī)律是認識高溫豎爐內(nèi)顆粒物料流動現(xiàn)象的基礎(chǔ)。本文針對準二維室溫填充床內(nèi)顆粒物料流動現(xiàn)象進行實驗和數(shù)學模型研究。以位于不同停留時間等值線上的示蹤顆粒分別標繪出中心和偏心卸料填充床內(nèi)穩(wěn)態(tài)物料流場(包括緩慢流動區(qū)和流動區(qū)),并研究了卸料速度對它的影響。以合適的物料流動表觀驅(qū)動力、物料流動阻力等的表達式為基礎(chǔ),根據(jù)質(zhì)量守恒、動量守恒原理建立了可以描述顆粒物料穩(wěn)態(tài)流動的數(shù)學模型。利用SIMPLE算法進行模型方程的離散求解。并利用實驗結(jié)果驗證了所建模型及其數(shù)值結(jié)果的可靠性。實驗和數(shù)學模型研究的主要結(jié)果為:①填充床內(nèi)存在明顯的物料流動區(qū)和緩慢流動區(qū),任一水平高度上物料流動速度沿橫向分布不均勻。中心卸料時,物料流動沿經(jīng)漏口的垂線占優(yōu)分布;偏心卸料時,在靠近壁面處形成物料流動的邊界層現(xiàn)象。卸料流量變化對流動區(qū)無明顯影響。②體積力方向的表觀驅(qū)動力的表達式反映了物料流場與體積力場的較強方位對應(yīng)關(guān)系和填充床內(nèi)流動區(qū)和死料區(qū)共存的現(xiàn)象;物料流動阻力的表達式說明物料表觀速度越大,物料流通性越好,通過慣性維持物料流動狀態(tài)的作用變強。③論文建立的連續(xù)介質(zhì)模型,能預(yù)測物料流動區(qū)、緩慢流動區(qū)和壁面附近的物料流動邊界層現(xiàn)象;實驗結(jié)果與模型計算結(jié)果吻合得較好。所建模型為動力學模型,與其他模型相比有較好的進一步發(fā)展的空間,為下一步研究填充床內(nèi)氣固兩相耦合、障礙物繞流現(xiàn)象、非穩(wěn)態(tài)卸料等奠定了基礎(chǔ)。本文研究工作對了解顆粒物流流動規(guī)律提供了一種比較簡單的數(shù)學模擬方法。為未來進一步研究豎爐、高爐等煉鐵工藝的模擬和優(yōu)化等提供了一種可能的手段。
[Abstract]:Particle flow is a common phenomenon in material preparation process, such as rare earth oxide preparation, iron and steel material preparation of blast furnace, shaft furnace process, and so on. The production efficiency is closely related to the quality of the product. It is important to understand the characteristics of the reactor by mastering the flow law of the material in the packed bed. It is very important to operate and control the reactor. It is the basis of understanding the particle material flow phenomenon in the high temperature shaft furnace to study the particle material flow law in the room temperature plant. This paper aims at the particle material flow in the quasi-two-dimensional room temperature packed bed. The steady state material flow field in the packed bed was plotted with the tracer particles located on the isoline of different residence time, respectively, and the steady state material flow field in the packed bed with eccentric discharge was plotted by using the image as an experimental and mathematical model. Including slow flow zones and flow zones). The influence of unloading speed on it is also studied. Based on the expression of material flow apparent driving force and material flow resistance, the mass conservation is carried out. The momentum conservation principle is used to establish a mathematical model which can describe the steady state flow of granular materials. The discrete solution of the model equation is carried out by using SIMPLE algorithm, and the experimental results are used to verify the model and its numerical results. Reliability. The main results of experimental and mathematical model studies are as follows:. 1 there are obvious material flow areas and slow flow areas in the packed bed. At any horizontal height, the velocity of material flow along the transverse distribution is uneven. When the material is discharged from the center, the material flow dominates along the vertical line through the leak. Eccentric discharge. The boundary layer phenomenon of material flow is formed near the wall. The expression of apparent driving force which has no obvious influence on the flow region by the change of discharge flow rate reflects the strong azimuth correspondence between the material flow field and the volume force field. Relationship and coexistence of flow zone and dead zone in packed bed; The expression of material flow resistance shows that the larger the apparent velocity of the material, the better the material circulation. The continuum model established in this paper can predict the material flow area through the inertial maintenance of the material flow state. 3. The material flow boundary layer phenomenon in the slow flow region and near the wall; The experimental results are in good agreement with the calculated results. The model is a dynamic model, compared with other models, there is a better room for further development, for the next step to study gas-solid coupling in the packed bed. The research work in this paper provides a simple mathematical simulation method for understanding the flow law of particle logistics and provides a simple mathematical simulation method for the further study of shaft furnace in the future. The simulation and optimization of ironmaking process such as blast furnace provide a possible means.
【學位授予單位】：重慶大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TF51

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