本文選題：填料塔 + 波紋結(jié)構(gòu)��； 參考：《浙江大學(xué)》2015年碩士論文

【摘要】：在化工生產(chǎn)過程中,氣液兩相間接觸面積的大小和液相湍動程度是影響傳熱傳質(zhì)效率的重要因素因素。薄膜流體因其高傳熱傳質(zhì)系數(shù)及動力消耗小等特點而備受青睞。填料表面波紋結(jié)構(gòu)能引起薄膜流動特性的改變,從而提高薄膜流體的傳熱傳質(zhì)效率。本文簡化填料結(jié)構(gòu),以不同形狀的波紋板為研究對象,探究波紋板表面薄膜流體流動特征,結(jié)合數(shù)值計算和實驗方法,開展了如下工作：(1)探究了重力驅(qū)動下薄膜流體沿傾斜波紋壁面下落的流動現(xiàn)象。使用開源計算流體力學(xué)軟件OpenFOAM進(jìn)行薄膜流動模擬,選擇基于VOF法的interFoam求解器進(jìn)行計算。將得到的模擬結(jié)果與文獻(xiàn)中的實驗結(jié)果進(jìn)行對比,驗證模型的正確性和可靠性。(2)探究了三種常見波紋板結(jié)構(gòu)—三角形、正弦形和矩形波紋板表面薄膜流動,進(jìn)行數(shù)值模擬分析。對流動過程中薄膜波動振幅、表面輪廓、法向速度分布等重要參數(shù)進(jìn)行對比,得出如下結(jié)論：三種波紋結(jié)構(gòu)在相同條件情況下,三角形的波紋結(jié)構(gòu)更有利于傳熱傳質(zhì)。(3)設(shè)計并搭建了用于薄膜流體流動顯示的試驗系統(tǒng),實驗以甘油和水的混合溶液為研究對象,測量了不同雷諾數(shù)時三種波紋結(jié)構(gòu)表面薄膜流體流動狀態(tài)。薄膜流體自由表面輪廓和流線圖與仿真結(jié)果進(jìn)行了對比,進(jìn)一步驗證了模型的正確性和實驗裝置的合理性。(4)研究了液體表面張力、液相粘度和波紋板傾斜角度對三角形波紋板表面薄膜流動的影響。發(fā)現(xiàn)表面張力存在與否可以引起整個流場的改變,所以在仿真計算過程中不能忽略表面張力動量源項,但在一定范圍內(nèi)表面張力大小對流場的影響不明顯。液相粘度較小時薄膜厚度較薄,波動較為劇烈；液相粘度較大時薄膜厚度較厚,波動比較平緩。波紋板傾斜角度對薄膜流動有一定的影響,在不同的傾斜角度范圍內(nèi),將改變薄膜流動發(fā)生共振時自由表面長度。(5)研究了三角形、矩形波紋板幾何結(jié)構(gòu)尺寸改變和矩形波紋板倒角形狀存在與否對薄膜流動的影響。雷諾數(shù)相同時,三角形波紋板和矩形波紋板的ζ值(高度與波長之比)越小薄膜波動越明顯。對于矩形波紋板結(jié)構(gòu)來說,有倒角存在的情況下矩形波紋板薄膜波動更明顯。(6)基于以上結(jié)果,進(jìn)一步探討了新型結(jié)構(gòu)—梯形波紋板和鋸齒形波紋板表面薄膜流體流動現(xiàn)象。發(fā)現(xiàn)梯形波紋板表面薄膜流體流動特性介于矩形板和三角形板之間。對于鋸齒形波紋板這種新型波紋結(jié)構(gòu)來說,薄膜波動情況明顯比三角形和矩形波紋板薄膜波動情況好,具有良好的薄膜波動特性,是一種值得考慮的新型填料結(jié)構(gòu)。
[Abstract]:In the process of chemical production, the contact area between gas and liquid phase and the degree of liquid phase turbulence are important factors affecting the efficiency of heat and mass transfer. Thin film fluid is favored for its high heat and mass transfer coefficient and low power consumption. The corrugated structure of the filler surface can change the flow characteristics of the film and improve the heat and mass transfer efficiency of the film fluid. In this paper, the packing structure is simplified, and different shapes of corrugated plates are taken as the research objects. The characteristics of fluid flow on the surface of the corrugated plates are investigated, combined with numerical calculation and experimental methods. The main works are as follows: (1) the flow phenomenon of thin film fluid falling along the inclined corrugated wall driven by gravity is investigated. The open source computational fluid dynamics software OpenFOAM is used to simulate the thin film flow, and the interFoam solver based on VOF method is selected for the calculation. The simulation results are compared with the experimental results in the literature to verify the correctness and reliability of the model. (2) three kinds of common corrugated plate structures-triangular, sinusoidal and rectangular corrugated plate surface film flow are investigated, and numerical simulation analysis is carried out. By comparing the film wave amplitude, surface profile, normal velocity distribution and other important parameters during the flow process, it is concluded that the three corrugated structures are under the same conditions. The triangular corrugated structure is more favorable for heat and mass transfer. (3) an experimental system for the display of fluid flow in thin film is designed and built. The mixed solution of glycerol and water is used as the object of the experiment. The flow state of thin film on the surface of three corrugated structures was measured with different Reynolds numbers. The free surface profile and streamline diagram of thin film fluid are compared with the simulation results, which further verify the correctness of the model and the reasonableness of the experimental device. (4) the surface tension of liquid is studied. The effect of liquid viscosity and inclined angle of corrugated plate on the flow of thin film on the surface of triangular corrugated plate. It is found that the existence of surface tension can cause the change of the whole flow field, so the momentum source term of surface tension can not be neglected in the course of simulation, but the effect of surface tension on the flow field is not obvious in a certain range. When the liquid viscosity is small, the film thickness is thinner and the fluctuation is more intense, while the film thickness is thicker and the fluctuation is more gentle when the liquid viscosity is larger. The inclined angle of the corrugated plate has a certain influence on the film flow. In the range of different inclined angles, the free surface length when the film flow resonates will be changed. (5) the triangle is studied. The influence of the geometric structure and the chamfering shape of rectangular corrugated plate on the thin film flow. At the same Reynolds number, the smaller the Zeta value (ratio of height to wavelength) of triangular and rectangular corrugated plates is, the more obvious the fluctuation is. For rectangular corrugated plate structure, the undulation of rectangular corrugated plate film is more obvious in the presence of chamfer angle. (6) based on the above results, the flow phenomenon of thin film on the surface of trapezoidal corrugated plate and sawtooth corrugated plate is further discussed. It is found that the flow characteristics of thin film on the surface of trapezoidal corrugated plate are between rectangular plate and triangular plate. For the new corrugated structure of zigzag corrugated plate, the undulation of thin film is obviously better than that of triangular and rectangular corrugated plates, and it is a new packing structure worthy of consideration.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB383.2;TQ053.5

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 王文坦;張夢雪;趙述芳;劉U，

本文編號：2090496