本文選題：新型大通量填料　切入點(diǎn)：流體力學(xué)性能　出處：《北京化工大學(xué)》2015年碩士論文

【摘要】：本文根據(jù)填料的發(fā)展規(guī)律及工業(yè)需求,針對(duì)填料的大通量使用條件,結(jié)合BH填料成功的設(shè)計(jì)經(jīng)驗(yàn),對(duì)傳統(tǒng)填料波紋結(jié)構(gòu)進(jìn)行改進(jìn),設(shè)計(jì)開發(fā)出A、B、C三種結(jié)構(gòu)獨(dú)特的新型大通量規(guī)整填料。常溫常壓下,在冷模實(shí)驗(yàn)裝置中以空氣-水-氧氣為介質(zhì)研究新型填料的流體力學(xué)和傳質(zhì)性能,并與傳統(tǒng)的大通量填料Mellapak125X對(duì)比。實(shí)驗(yàn)結(jié)果表明,三種新型填料的干塔壓降分別比Mellapak125X下降15.3%、23.8%和35%；濕塔壓降分別下降26.7%、34.2%和40.3%；液泛氣速分別提高7.5%、11.3%和15.1%。在三種新型填料中,A型填料具有最高的傳質(zhì)效率,但通量較小；而C型填料雖然通量最大,但傳質(zhì)效率卻有一定程度的下降。計(jì)算流體力學(xué)(CFD)技術(shù)是流體力學(xué)理論與現(xiàn)代計(jì)算機(jī)科學(xué)結(jié)合的產(chǎn)物,廣泛地應(yīng)用在科研、制造等領(lǐng)域。但由于填料復(fù)雜的結(jié)構(gòu)及填料內(nèi)兩相流動(dòng)的復(fù)雜性,填料的CFD模擬尚未得到廣泛應(yīng)用。本文建立了多尺度CFD模型,以局部的VOF模型為基礎(chǔ),對(duì)新型填料(A型)的干、濕塔壓降進(jìn)行了模擬計(jì)算,并對(duì)不同氣液速度下填料表面平均液膜厚度及有效接觸面積變化進(jìn)行了闡述。模擬結(jié)果表明：采用該多尺度模型計(jì)算填料的干塔壓降與實(shí)驗(yàn)值誤差為5.2%；除個(gè)別點(diǎn)誤差較大外,模擬的填料濕塔壓降與實(shí)驗(yàn)值誤差在20%以內(nèi)。當(dāng)氣速為0時(shí),填料表面液膜厚度隨液體流速的增加呈線性遞增變化；有效接觸面積隨液體流速的增大有增加的趨勢(shì),但增加量逐漸減小。固定液體流量,在低氣速范圍內(nèi)增加氣速,填料表面平均液膜厚度與有效接觸面積有增加的趨勢(shì),但不明顯；當(dāng)接近液泛區(qū)域時(shí),隨著氣速的增加,平均液膜厚度及有效接觸面積有明顯的上升趨勢(shì)。該現(xiàn)象表明,氣速較小時(shí),氣液兩相交互作用較小,氣速對(duì)液相分布行為影響�。浑S著氣速的增加,氣液交互作用逐漸增強(qiáng),氣速對(duì)液相分布具有較大的影響。本文提出的多尺度模型計(jì)算量較小、精度較高,將填料的宏觀和微觀性質(zhì)相結(jié)合,在計(jì)算填料壓降的同時(shí),還得到了填料局部的流場(chǎng)信息,在填料的理論研究和改進(jìn)設(shè)計(jì)中具有一定的應(yīng)用價(jià)值。
[Abstract]:In this paper, according to the development law of packing and industrial demand, according to the condition of large flux of packing, combined with the successful design experience of BH packing, the corrugated structure of traditional packing is improved. Three new types of large flux regular fillers with unique structure are designed and developed. The hydrodynamics and mass transfer properties of the new fillers are studied by using air-water-oxygen as the medium in a cold model experimental device at room temperature and atmospheric pressure. Compared with the traditional high-flux packing Mellapak125X, the experimental results show that, The dry column pressure drop of the three new types of packing is 15.33.8and 35% lower than that of Mellapak125X respectively, the pressure drop of wet tower is 26.732% and 40.3% respectively, the liquid gas velocity increases 7.511.3% and 15.1g, respectively. Among the three new fillers, the type A packing has the highest mass transfer efficiency, but the flux is relatively small. Although the fluxes of C type fillers are the largest, the mass transfer efficiency decreases to a certain extent. Computational fluid dynamics (CFD) technology is the product of the combination of fluid mechanics theory and modern computer science, and is widely used in scientific research. However, due to the complex structure of fillers and the complexity of two-phase flow in fillers, the CFD simulation of fillers has not been widely used. In this paper, a multi-scale CFD model is established, based on the local VOF model. The pressure drop of dry and wet tower is simulated and calculated. The variation of average liquid film thickness and effective contact area of packing surface at different gas-liquid velocities are described. The simulation results show that the error between the pressure drop of dry tower and the experimental value of packing is 5.2 by using the multi-scale model, except for some points, the error is large. When the gas velocity is 0, the thickness of liquid film on the packing surface changes linearly with the increase of liquid velocity, and the effective contact area increases with the increase of liquid velocity. But the increase gradually decreased. When the liquid flow rate was fixed, the gas velocity increased in the range of low gas velocity, the average liquid film thickness and the effective contact area on the packing surface increased, but not obvious. The average liquid film thickness and the effective contact area have an obvious upward trend. This phenomenon shows that the gas-liquid two-phase interaction is smaller and the gas velocity has little effect on the liquid phase distribution behavior with the increase of the gas-liquid velocity, the gas-liquid interaction increases gradually with the increase of the gas-liquid velocity. The gas velocity has a great influence on the liquid phase distribution. The multi-scale model proposed in this paper has the advantages of low computational complexity and high precision. Combining the macroscopic and microscopic properties of the packing, the pressure drop of the packing is calculated and the local flow field information is obtained. It has certain application value in theoretical research and improved design of filler.
【學(xué)位授予單位】：北京化工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TQ050.45

【參考文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 黃瑩;規(guī)整填料特征單元內(nèi)流動(dòng)與混合過(guò)程的CFD研究[D];天津大學(xué);2006年

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本文編號(hào)：1690916